U.S. patent application number 10/505072 was filed with the patent office on 2005-06-09 for method and system for assessing eye disease.
This patent application is currently assigned to Notal Vision Ltd.. Invention is credited to Alster, Yair, Azmon, Barak, Rafaeli, Omer.
Application Number | 20050122477 10/505072 |
Document ID | / |
Family ID | 27757575 |
Filed Date | 2005-06-09 |
United States Patent
Application |
20050122477 |
Kind Code |
A1 |
Alster, Yair ; et
al. |
June 9, 2005 |
Method and system for assessing eye disease
Abstract
Methods and a device comprising a controller/processor unit
(664), a visual test-pattern unit (660), a competing sensory
stimuli generating unit (662), a user input device (666), an ouput
device (668) and a storage unit (670) for detecting eye disease and
for assessing the clinical stage of an eye disease in an individual
is disclosed. The methods include projecting test patterns onto the
retina of a tested eye and subjecting the individual to a competing
sensory stimuli. The competing stimuli may be of various different
sensory modalities including visual, auditory, or other sensory
modalities. If the individual perceives a difference in at least
one localized part of the perceived image of a test pattern as
compared to a predefined reference pattern, the individual provides
a response indicative of the difference or differences. The
responses are processed to assess the severity of eye disease if a
disease is detected, or to determine the clinical stage of a
detected eye disease.
Inventors: |
Alster, Yair; (Tel-Aviv,
IL) ; Rafaeli, Omer; (Tel-Aviv, IL) ; Azmon,
Barak; (Tel-Aviv, IL) |
Correspondence
Address: |
William H Dippert
Reed Smith
29th Floor
599 Lexington Avenue
New York
NY
10022-7650
US
|
Assignee: |
Notal Vision Ltd.
Tel-Aviv
IL
|
Family ID: |
27757575 |
Appl. No.: |
10/505072 |
Filed: |
August 18, 2004 |
PCT Filed: |
February 19, 2003 |
PCT NO: |
PCT/IL03/00135 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60357115 |
Feb 19, 2002 |
|
|
|
Current U.S.
Class: |
351/237 |
Current CPC
Class: |
A61B 3/032 20130101;
A61B 3/02 20130101 |
Class at
Publication: |
351/237 |
International
Class: |
A61B 003/02 |
Claims
1-72. (canceled)
73. A method for obtaining data on the vision of an individual,
comprising: presenting, for a first duration, a test pattern to the
individual, to allow the individual to form a perceived image of
said test pattern; receiving from said individual, input indicative
of a difference between said perceived image and the test pattern,
if said individual perceived difference, the presenting and
receiving being repeated one or more times, wherein for at least
one of the repetitions, said individual is subjected to a competing
sensory stimulus; and analyzing the received input to determine
information on the vision of said individual, wherein the analysis
is at least partially responsive to one or more characteristics of
said competing sensory stimulus.
74-143. (canceled)
144. A method according to claim 73, wherein said first duration is
in the range of 100-160 milliseconds.
145. A method according to claim 73, wherein analyzing the received
input comprises analyzing to determine whether the individual has
an eye disease.
146. A method according to claim 73, wherein analyzing the received
input comprises determining if said individual belongs to a group
having a defined clinical stage of an eye disease.
147. A method according to claim 73, wherein said eye disease is
selected from the group consisting of age-related macular
degeneration, choroidal neovascularization, ocular histoplasmosis,
myopia, central serous retinopathy, central serous choroidopathy,
glaucoma, diabetic retinopathy, media opacities, cataract,
retinitis pigmentosa, optic neuritis, epiretinal membrane, vascular
abnormalities, vascular occlusions, choroidal dystrophies, retinal
dystrophies, macular hole, choroidal degeneration, retinal
degeneration, lens abnormalities, and combinations thereof.
148. A method according to claim 73, wherein the analysis is at
least partially responsive to the magnitude of the competing
sensory stimulus.
149. A method according to claim 73, wherein the analysis is at
least partially responsive to the position and/or orientation of
the test pattern.
150. A method according to claim 73, wherein the analysis is at
least partially responsive to patient indications of locations
within the patterns of the differences between the perceived image
and the test pattern.
151. A method according to claim 73, wherein the competing stimulus
in at least one of the repetitions is presented only before the
presenting of the test pattern.
152. A method according to claim 73, wherein the competing stimulus
in at least one of the repetitions is presented only during at
least part of the first duration.
153. A method according to claim 73, wherein the competing stimulus
in at least one of the repetitions is presented after at least part
of the first duration.
154. A method according to claim 73, wherein the individual is
subjected to the competing sensory stimulus during a period
substantially coinciding with the first duration.
155. A method according to claim 73, wherein at least one of the
competing stimuli comprises a stimulus that changes over the time
in which the individual is subjected to the stimulus.
156. A method according to claim 73, wherein the competing stimulus
comprises an auditory stimulus.
157. A method according to claim 73, wherein the competing stimulus
comprises a visual stimulus.
158. A method according to claim 73, wherein the competing stimulus
comprises a tactile stimulus.
159. A method according to claim 73, wherein the competing stimulus
comprises a nociceptive or a somatosensory stimulus.
160. A method according to claim 73, wherein the competing stimulus
is not a distortion of the test pattern.
161. A method according to claim 73, wherein the competing stimulus
is different for at least some of the repetitions.
162. A method according to claim 161, wherein the competing
stimulus of different repetitions has different durations or
different beginning times relative to the first duration.
163. A method according to claim 161, wherein the competing
stimulus of different repetitions has a different magnitude.
164. A method according to claim 161, wherein the competing
stimulus of different repetitions has a different shape, pattern,
color, or intensity.
165. A method according to claim 73, wherein said competing
stimulus is not a part of the test pattern.
166. A method according to claim 73, wherein said competing
stimulus is a noisy visual background of the test pattern.
167. A method according to claim 73, wherein said competing
stimulus is within the test pattern.
168. A method according to claim 167, wherein said competing
stimulus comprises an artificial distortion which mimics the
appearance of a distortion perceived by an individual when the test
pattern is presented at a location of the retina of the individual
which comprises an abnormality.
169. A method according to claim 167, wherein at least one of the
inputs of the individual are analyzed to determine a probability
that the input is due to the competing stimulus.
170. A method according to claim 167, wherein the indications are
given a weight for use in the analysis responsive to a distance
between the indications and the competing stimulus.
171. A method according to claim 73, comprising fixating the
individual's vision at or about a fixation target before presenting
the test pattern.
172. A method according to claim 73, wherein receiving input
indicative of a difference between the perceived image and the test
pattern comprises receiving input on a temporary distortion of the
test pattern.
173. A method according to claim 73, wherein receiving input
indicative of a difference between the perceived image and the test
pattern comprises receiving input on perceived relative motion in
the test pattern.
174. A method according to claim 73, wherein receiving input
indicative of a difference between the perceived image and the test
pattern comprises receiving input on a misaligned segment in the
perceived image of the test pattern.
175. A method according to claim 73, wherein receiving input
indicative of a difference between the perceived image and the test
pattern comprises receiving input on a blurring of the perceived
image relative to the test pattern.
176. A method according to claim 73, wherein the test pattern is
presented at different locations in at least some of the
repetitions.
177. A method according to claim 176, wherein the different
locations of the test pattern map a selected region of a patient's
retina at a desired resolution.
178. A method according to claim 73, wherein the test pattern is
presented with different orientations in at least some of the
repetitions.
179. A method according to claim 73, wherein said test pattern is a
straight line or a segmented straight line.
180. A method according to claim 73, wherein presenting the test
pattern comprises displaying on a display device or projecting with
a beam scanning device.
181. A method for obtaining data on an eye in an individual,
comprising: presenting for a first duration a test pattern to the
individual, to allow the individual to form a perceived image of
said test pattern; receiving from said individual, input indicative
of a difference between said perceived image and the test pattern,
if said individual perceived a difference; and the presenting and
receiving being repeated one or more times, wherein for at least
one of the repetitions said individual is subjected to a
predetermined visual competing sensory stimulus, within the test
pattern; and analyzing the received input to determine information
on an eye of said individual.
182. A method according to claim 181, wherein the competing
stimulus of different repetitions have different magnitudes.
183. A method according to claim 182, wherein the analysis is at
least partially responsive to the magnitude of the competing
sensory stimulus.
184. A method according to claim 181, wherein said first duration
is in the range of 100-160 milliseconds.
185. Apparatus for eye analysis, comprising: a pattern presenting
unit; an input device operative to receive input from an
individual; and a processing unit adapted to generate one or more
patterns to be presented sequentially to the individual through the
pattern presenting unit, to generate a competing stimulus to which
the individual is subjected with relation to at least one of the
test patterns, to receive, through the input device, input
indications representing, for at least one of the test patterns, a
difference observed by said individual between a perceived image of
the test pattern and the test pattern, and to analyze the received
input indications to determine information on the vision of the
individual.
186. Apparatus according to claim 185, wherein the processing unit
is adapted to analyze the input indications at least partially
responsive to one or more characteristics of the competing stimulus
corresponding to one or more of the test patterns.
187. Apparatus according to claim 186, wherein the processing unit
is adapted to analyze the input indications at least partially
responsive to a magnitude of the competing stimulus corresponding
to one or more of the test patterns.
188. Apparatus according to claim 185, wherein the processing unit
is adapted to generate for each of a plurality of the presented
patterns, a competing stimulus with a magnitude level, the
magnitude levels of at least two of the competing stimulus being
different from each other.
189. Apparatus according to claim 185, wherein the processing unit
is adapted to provide an indication on whether the individual has
an eye disease.
190. Apparatus according to claim 185, wherein the processing unit
is adapted to provide an indication on whether the individual
belongs to a group having a defined clinical stage of an eye
disease.
191. Apparatus according to claim 185, wherein processing unit is
adapted to receive indications of locations within the patterns of
the differences between the perceived image and the test
pattern.
192. Apparatus according to claim 185, wherein the generated
competing stimuli are presented to the patient through the pattern
presenting unit.
193. Apparatus according to claim 192, wherein the processing unit
is adapted to assign the input indications weights responsive to a
distance between the indications and the competing stimuli.
194. Apparatus according to claim 192, wherein at least one of the
competing sensory stimuli comprises a blurring of a segment of the
test pattern.
195. Apparatus according to claim 192, wherein at least one of the
competing sensory stimuli comprises a change in the shape of the
test pattern.
196. Apparatus according to claim 185, comprising a speaker and
wherein the competing stimuli are provided to the individual
through the speaker.
197. Apparatus according to claim 185, wherein the competing
stimulus with relation to at least one of the test patterns is
provided to the individual at least partially before or after the
test pattern is presented.
198. Apparatus according to claim 185, wherein the processing unit
analyzes at least one of the inputs of the individual to determine
a probability that the input is due to a competing stimulus.
199. Apparatus according to claim 185, wherein the processing unit
is adapted to generate at least some of the one or more patterns to
be presented sequentially, in different locations on the eye of the
individual.
200. Apparatus according to claim 185, comprising a competing
stimuli generating unit adapted to provide the individual with
tactile stimuli.
201. Apparatus according to claim 185, wherein the pattern
presenting unit comprises a display device or a beam scanning
device.
Description
FIELD OF THE INVENTION
[0001] This invention generally relates to systems, devices, and
methods for administering eye tests and for detecting, assessing,
and classifying eye disease in patients.
BACKGROUND OF THE INVENTION
[0002] Age-related macular degeneration (AMD) is the leading cause
of blindness among people over the age of 50 in the western world.
It is a bilateral, although asymmetric disease, and comes in two
forms. Dry or non-neovascular AMD is the more common and milder
form of AMD, accounting for 85-90% of all AMD. The key identifier
for dry AMD is small, round, white-yellow lesions (also known as
Drusen) in the macula. Vision loss associated with dry AMD is far
less dramatic than in the case of wet AMD. Recent publications
indicate that dietary supplements including antioxidants and
minerals reduce the progression of advanced AMD by 25% in patients
with intermediate (non-vascular) AMD. It is estimated that as many
as 14 million people suffer from dry AMD in the United States
alone.
[0003] Wet AMD is less prevalent than the dry form, accounting for
about 10-15% of AMD cases. The term "wet" denotes choroidal
neovascularization (CNV), in which abnormal blood vessels develop
beneath the retinal pigment epithelium (RPE) layer of the retina.
Wet AMD is characterized by the development of choroidal
angiogenesis which causes severe, and potentially rapid, visual
deterioration. The visual distortion typically consists of
perceiving straight lines as curved due to deformation of the
retina in a region overlying the choroidal angiogenesis. The wet
form of AMD accounts for about 60% of all cases of adult blindness
in the United States. In the U.S. alone there are 200,000 new cases
of wet AMD every year and a total of 1.7 million blind people from
AMD.
[0004] Treatment modalities for wet AMD may include laser
photocoagulation and Photodynamic therapy (PDT). Experimental
treatments that are under current investigation include feeder
vessel coagulation and trans-pupillary thermotherapy (TTT). All
these proven or experimental therapies may halt or slow progression
of the disease and will usually not improve visual function.
Therefore, early detection is crucial to prevent severe visual
loss.
[0005] Since approximately 12% of dry AMD cases develop wet AMD and
subsequent blindness within 10 years, a patient diagnosed with dry
AMD must be routinely examined by an ophthalmologist once or twice
a year, depending on the severity of his condition. The patient is
usually also given a so-called "Amsler grid" for weekly
self-examination at home for symptoms of wet AMD. The patient is
advised to consult an ophthalmologist immediately in the event that
symptoms are noticed. The Amsler grid and its modifications (such
as the "threshold Amsler" or the "red Amsler") have been shown to
be poor detectors of early changes associated with wet AMD for
several reasons. One reason is the phenomenon of "filling-in"
whereby the brain fills in missing parts in the pattern or corrects
defects or distortions in the pattern. The subject thus fails to
perceive a distorted pattern as being distorted. Another problem
with the Amsler grid is the inability of patients to adequately
fixate their vision on a fixed point while taking the test. The
Amsler test also suffers from low compliance stemming from the
non-interactive nature of the test.
[0006] The degree of visual deterioration is a function of the size
of the lesion and its proximity to the fovea at the time of
diagnosis. Although most lesions probably start outside the foveal
area, 70% of the lesions are already foveal and large (>1500
microns) at the time of diagnosis. It is therefore crucial to
identify the lesions at the earliest possible stage, while they are
still small and have not reached the fovea. It is known that 70% of
lesions diagnosed as treatable become untreatable within less than
three months, which indicates that the progression of the disease
is relatively rapid. As many as 50% of patients with wet AMD are
already ineligible for treatment when they first consult their
ophthalmologist because the disease has progressed considerably.
This is due to the poor validity of existing self-assessment
methods for detecting an AMD-related lesion at an early stage, and
the time lapsed between noticing the symptoms and seeing an
ophthalmologist.
[0007] A reliable method for diagnosing wet AMD at the earliest
possible stage, in conjunction with a referral system aimed at
lowering the incidence of visual deterioration in this devastating
disease, are imperative. If detected early, laser therapy to
destroy the abnormal blood vessels may prevent additional vision
loss. It is therefore crucial to detect the transition from dry to
wet AMD as early as possible.
[0008] Furthermore, there is a long felt need for simple and
inexpensive methods for classifying or assessing the stages of a
visual disorder such as in patients with AMD.
SUMMARY OF THE INVENTION
[0009] There is therefore provided in accordance with an embodiment
of the present invention a method for detecting eye disease in an
individual. the method includes the steps of:
[0010] (a) projecting a first pattern on a first location on the
retina of an eye of the individual;
[0011] (b) fixating the individual's vision on a fixation target
projected on the retina at or about the first location;
[0012] (c) hiding at least a portion of the first pattern;
[0013] (d) projecting a second pattern on a second location of the
retina to allow the individual to form a perceived image of the
second pattern;
[0014] (e) receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected a difference;
[0015] (f) repeating steps (a) to (e) a number of times to obtain a
plurality of data, wherein in at least some of the repetitions of
steps (a) to (e), the individual is subjected to a competing
sensory stimulus; and
[0016] (g) processing the plurality of data to determine if the
individual belongs to a group having a defined clinical stage of an
eye disease.
[0017] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is a sensory
stimulus effective in modifying the ability of the individual to
report a difference in at least one localized part of the perceived
image as compared to a predefined reference pattern when the
difference is perceived due to the eye disease.
[0018] Furthermore, in accordance with another embodiment of the
present invention, steps (a) to (g) are performed in the order
recited above.
[0019] Furthermore, in accordance with another embodiment of the
present invention, the hiding is performed in response to the
fixating.
[0020] Furthermore, in accordance with another embodiment of the
present invention, the eye disease is selected from the group
consisting of age-related macular degeneration, choroidal
neovascularization, ocular hystoplasmosis, myopia, central serous
retinopathy, central serous choroidopathy, glaucoma, diabetic
retinopathy, media opacities, cataract, retinitis pigmentosa, optic
neuritis, epiretinal membrane, vascular abnormalities, vascular
occlusions, choroidal dystrophies, retinal dystrophies, macular
hole, choroidal degeneration, retinal degeneration, lens
abnormalities, and combinations thereof.
[0021] Furthermore, in accordance with another embodiment of the
present invention, steps (a) to (e) are repeated while changing the
position of at least one of the first pattern and the second
pattern to map a selected region of the retina at a desired
resolution.
[0022] Furthermore, in accordance with another embodiment of the
present invention, steps (a) to (e) are repeated while changing the
orientation of the first pattern and of the second pattern.
[0023] Furthermore, in accordance with another embodiment of the
present invention, competing stimulus is selected from a competing
stimulus presented before the projecting of the second pattern, a
competing stimulus presented during at least part of the duration
of projecting of the second pattern, a competing stimulus presented
after the projecting of the second pattern and a competing stimulus
which temporally overlaps at least a part of the duration of the
projecting of the second pattern.
[0024] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is selected from a fixed
stimulus, a varying stimulus and a transient stimulus.
[0025] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is selected from a
stimulus which does not vary for the duration of presentation of
the second pattern and a stimulus which varies within the duration
of presentation of the second pattern.
[0026] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is selected from
a visual stimulus, an auditory stimulus, a somatosensory stimulus,
a tactile stimulus, and a nociceptive stimulus.
[0027] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is a distracting sensory
stimulus.
[0028] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is a visual
stimulus which is not a part of the first pattern or of the second
pattern.
[0029] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is an auditory
stimulus selected from a single frequency sound and a
multi-frequency sound.
[0030] Furthermore, in accordance with another embodiment of the
present invention, at least one parameter of the competing sensory
stimulus is modified in one or more of the repetitions of steps (a)
to (e).
[0031] Furthermore, in accordance with another embodiment of the
present invention, the at least one parameter is selected from the
duration of the competing stimulus, the time of initiating the
presenting of the competing sensory stimulus relative to the time
of projecting of the second pattern, one or more characteristics of
the competing sensory stimulus, and combinations thereof.
[0032] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is an auditory
stimulus, and the at least one parameter of said auditory stimulus
which is modified is selected from the intensity of the auditory
stimulus, the waveform of the auditory stimulus, the frequency of
the auditory stimulus, the frequency distribution of the auditory
stimulus, the frequency content of the auditory stimulus, the
duration of the auditory stimulus, the envelope of the auditory
stimulus and combinations thereof.
[0033] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is a visual
stimulus and the at least one parameter of said competing stimulus
which is modified is selected from the size of the stimulus, the
shape of the stimulus, the pattern of the stimulus, the duration of
presentation of the stimulus, the color of the stimulus, the
intensity of the stimulus, the luminance of the stimulus, the
chrominance of the stimulus, the temporal variation of the
stimulus, the timing of presentation of the stimulus to the
individual, the position of projecting the stimulus on the retina,
the position of the stimulus on said retina, the rate of movement
of said stimulus on said retina, and combinations thereof.
[0034] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is a visual stimulus
selected from a visual stimulus which is a part of the second
pattern and a visual stimulus which is not a part of the second
pattern.
[0035] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is a noisy visual
background projected on the retina.
[0036] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is selected from a
stimulus which does not vary for the duration of presentation of
the second pattern and a stimulus which varies within the duration
of presentation of the second pattern.
[0037] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus comprises an
artificial distortion introduced into the second pattern.
[0038] Furthermore, in accordance with another embodiment of the
present invention, the artificial distortion introduced into the
second pattern mimics the appearance of the distortion perceived by
an individual when a test pattern identical to the reference
pattern is projected at a location of the retina of the individual
which comprises a retinal or choroidal abnormality or a retinal and
a choroidal abnormality.
[0039] Furthermore, in accordance with another embodiment of the
present invention, the artificial distortion comprises at least a
portion of the second pattern which is perceivably different than
the corresponding part of the reference pattern.
[0040] Furthermore, in accordance with another embodiment of the
present invention, the artificial distortion is selected from at
least one portion of the second pattern which is distorted or
shifted in comparison with the reference pattern, at least one
optical property of at least one part of the second pattern which
is different than the corresponding optical property of the
remaining part of the second pattern, at least one portion of the
second pattern which is visibly different in comparison with the
corresponding portion of the reference pattern, at least one
portion of the second pattern is missing in comparison with said
reference pattern, and at least one portion of the second pattern
which is blurred in comparison with the remaining part of the
second pattern.
[0041] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is selected from
a fixed visual stimulus, a time varying visual stimulus, and a
transient visual stimulus.
[0042] Furthermore, in accordance with another embodiment of the
present invention, the first pattern, the reference pattern, and
the second pattern are selected from a straight line and a
segmented straight line.
[0043] Furthermore, in accordance with another embodiment of the
present invention, the plurality of data of step (e) includes for
each repetition of steps (a) to (e) one or more data items selected
from the group consisting of data representing the position on the
retina of the second pattern, data representing the orientation of
the second pattern, data representing the position within the
second pattern of the at least one localized part of the
difference, and data representing one or more characteristics of
the competing sensory stimulus.
[0044] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is a visual competing
stimulus included in the second pattern and the plurality of data
further includes data representing the position of the visual
competing stimulus within the second pattern.
[0045] Furthermore, in accordance with another embodiment of the
present invention, the step of processing includes determining for
at least one group of competing sensory stimuli having common
stimulus parameters the value of a competition grade and
determining if the individual belongs to a group having a specific
clinical stage of the eye disease based on the determined value of
the competition grade.
[0046] Furthermore, in accordance with another embodiment of the
present invention, the competition grade represents the efficiency
of a group of competing sensory stimuli having common stimulus
parameters in preventing the tested individual from reporting the
presence of the difference of the perceived image, when said
difference is caused by the eye disease.
[0047] Furthermore, in accordance with another embodiment of the
present invention, the value of the competition grade is computed
as the percentage of projected second patterns for which the
individual reported at least one localized difference, caused by
the eye disease, between the perceived image of the second pattern
and the reference pattern, out of the total number of projected
second patterns for which the individual was subjected to competing
sensory stimuli belonging to a group of competing sensory stimuli
having common stimulus parameters.
[0048] Furthermore, in accordance with another embodiment of the
present invention, the second pattern is a segmented straight line,
the competing sensory stimulus includes one or more segments of the
segmented line which are shifted relative to the remaining segments
of the straight line to form an artificial distortion having a
defined amplitude. The position of the artificial distortion along
the segmented straight line varies in at least some repetitions of
the projecting of the second pattern, and within each group of
competing sensory stimuli having common stimulus parameters, the
amplitude of the artificial distortion is the same.
[0049] Furthermore, in accordance with another embodiment of the
present invention, the second pattern is a segmented straight line,
said competing sensory stimulus comprises one or more segments of
said segmented line which are shifted relative to the remaining
segments of said straight line to form an artificial distortion
having a defined amplitude, and wherein said at least one localized
difference is determined to be caused by said eye disease if the
computed distance between the center of said artificial distortion
and the position along the length of said segmented line at which
said individual reported said at least one localized difference
exceeds a preset value.
[0050] There is further provided, in accordance with a embodiment
of the present invention, a method for obtaining data useful for
detecting eye disease in an individual, the method includes the
steps of:
[0051] (a) projecting a first pattern on a first location on the
retina of an eye of the individual;
[0052] (b) fixating the individual's vision on a fixation target
projected on the retina at or about the first location;
[0053] (c) hiding at least a portion of the first pattern;
[0054] (d) projecting a second pattern on a second location of the
retina to allow the individual to form a perceived image of the
second pattern;
[0055] (e) receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected such a difference; and
[0056] (f) repeating steps (a) to (e) a number of times, wherein
for at least some of the repetitions of steps (a) to (e), the
individual is subjected to a competing sensory stimulus to obtain a
plurality of data useful for detecting eye disease in the
individual.
[0057] There is further provided, in accordance with a embodiment
of the present invention, a method for detecting eye disease in an
individual. The method includes the steps of:
[0058] fixating the individual's vision at or about a fixation
target projected at a first retinal location of the retina of an
eye of the individual;
[0059] projecting for a first duration a test pattern at a second
retinal location of the eye, to allow the individual to form a
perceived image of the test pattern;
[0060] receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected such a difference;
[0061] repeating the steps of fixating, projecting and receiving a
number of times to obtain a plurality of data, wherein in at least
some of the repetitions of the steps of fixating, projecting, and
receiving, the individual is subjected for a second duration to a
competing sensory stimulus; and
[0062] processing the plurality of data to determine if the
individual belongs to a group having a defined clinical stage of
the eye disease.
[0063] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is a sensory
stimulus effective in modifying the ability of the individual to
report a difference in at least one localized part of the perceived
image as compared to a predefined reference pattern when the
difference is perceived due to the eye disease.
[0064] Furthermore, in accordance with another embodiment of the
present invention, the first duration is in the range of 10
milliseconds to 20 seconds.
[0065] Furthermore, in accordance with another embodiment of the
present invention, the first duration is in the range of 100-160
milliseconds.
[0066] Furthermore, in accordance with another embodiment of the
present invention, the step of fixating, the step of projecting,
the step of receiving, the step of repeating and the step of
analyzing are performed in the order recited above.
[0067] Furthermore, in accordance with another embodiment of the
present invention, the projecting is performed in response to the
fixating.
[0068] Furthermore, in accordance with another embodiment of the
present invention, the eye disease is selected from the group
consisting of age-related macular degeneration, choroidal
neovascularization, ocular hystoplasmosis, myopia, central serous
retinopathy, central serous choroidopathy, glaucoma, diabetic
retinopathy, media opacities, cataract, retinitis pigmentosa, optic
neuritis, epiretinal membrane, vascular abnormalities, vascular
occlusions, choroidal dystrophies, retinal dystrophies, macular
hole, choroidal degeneration, retinal degeneration, lens
abnormalities, and combinations thereof.
[0069] Furthermore, in accordance with another embodiment of the
present invention, in at least some of the repetitions of the steps
of fixating, projecting, and receiving, the position of projecting
of the test pattern on the retina is changed to map a selected
region of the retina at a desired resolution.
[0070] Furthermore, in accordance with another embodiment of the
present invention, in at least some of the repetitions of the steps
of fixating, projecting, and receiving, the orientation of
projecting of the test pattern on the retina is changed.
[0071] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is selected from
a competing stimulus presented before the projecting of the test
pattern, a competing stimulus presented during at least part of the
duration of projecting of the test pattern, a competing stimulus
presented after the projecting of the test pattern, and a competing
stimulus which temporally overlaps at least a part of the duration
the projecting of the test pattern.
[0072] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is selected from a fixed
stimulus, a varying stimulus and a transient stimulus.
[0073] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is selected from a
stimulus which does not vary for the duration of presentation of
the test pattern and a stimulus which varies within the duration of
presentation of the test pattern.
[0074] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is selected from
a visual stimulus, an auditory stimulus, a somatosensory stimulus,
a tactile stimulus, and a nociceptive stimulus.
[0075] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is a distracting
sensory stimulus.
[0076] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is a visual
stimulus which is not a part of the test pattern.
[0077] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is an auditory
stimulus selected from a single frequency sound and a
multi-frequency sound.
[0078] Furthermore, in accordance with another embodiment of the
present invention, at least one parameter of the competing sensory
stimulus is modified in one or more of the repetitions of the steps
of fixating, projecting, and receiving.
[0079] Furthermore, in accordance with another embodiment of the
present invention, the at least one parameter which is modified is
selected from the duration of the competing stimulus, the time of
initiating the presenting of the competing sensory stimulus
relative to the time of projecting of the test pattern, one or more
characteristics of the competing sensory stimulus, and combinations
thereof.
[0080] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is an auditory
stimulus. The at least one parameter of the auditory stimulus which
is modified is selected from the intensity of the auditory
stimulus, the waveform of the auditory stimulus, the frequency of
the auditory stimulus, the frequency distribution of the auditory
stimulus, the frequency content of the auditory stimulus, the
duration of the auditory stimulus, the envelope of the auditory
stimulus and combinations thereof.
[0081] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is a visual
stimulus and the at least one parameter of the competing stimulus
which is modified is selected from the size of the stimulus, the
shape of the stimulus, the pattern of the stimulus, the duration of
presentation of the stimulus, the color of the stimulus, the
intensity of the stimulus, the luminance of the stimulus, the
chrominance of the stimulus, the temporal variation of the
stimulus, the timing of presentation of the stimulus to the
individual, the position of projecting the stimulus on the retina,
the rate of movement of the stimulus on the retina, and
combinations thereof.
[0082] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is a visual stimulus
selected from a visual stimulus which is a part of the test pattern
and a visual stimulus which is not a part of the test pattern.
[0083] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is a noisy visual
background projected on the retina.
[0084] Furthermore, in accordance with another embodiment of the
present invention, the sensory stimulus is selected from a stimulus
which does not vary for the duration of presentation of the test
pattern and a stimulus which varies within the duration of
presentation of the test pattern.
[0085] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus includes an
artificial distortion introduced into the test pattern.
[0086] Furthermore, in accordance with another embodiment of the
present invention, the artificial distortion introduced into the
test pattern mimics the appearance of the distortion perceived by
an individual when a test pattern identical to the reference
pattern is projected at a location of the retina of the individual
which includes a retinal abnormality, or a choroidal abnormality,
or a retinal and a choroidal abnormality.
[0087] Furthermore, in accordance with another embodiment of the
present invention, the artificial distortion comprises at least a
portion of the test pattern which is perceivably different than the
corresponding part of the reference pattern.
[0088] Furthermore, in accordance with another embodiment of the
present invention, the artificial distortion is selected from at
least one portion of the test pattern being distorted or shifted in
comparison with the reference pattern, at least one optical
property of at least one part of the test pattern being different
than the corresponding optical property of the remaining part of
the test pattern, at least one portion of the test pattern is
visibly different in comparison with the corresponding portion of
the reference pattern, at least one portion of the test pattern is
missing in comparison with the reference pattern, and at least one
portion of the test pattern being blurred in comparison with the
remaining part of the test pattern.
[0089] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimulus is selected from
a fixed visual stimulus, a time varying visual stimulus, and a
transient visual stimulus.
[0090] Furthermore, in accordance with another embodiment of the
present invention, the test pattern, and the reference pattern is
selected from a straight line and a segmented straight line.
[0091] Furthermore, in accordance with another embodiment of the
present invention, the plurality of data of the step of repeating
includes, for each repetition of the steps of fixating, projecting
and receiving, one or more data items selected from the group
consisting of, data representing the position on the retina of the
test pattern, data representing the orientation of the test
pattern, data representing the position within the test pattern of
the at least one localized part of the difference, and data
representing one or more characteristics of the competing sensory
stimulus.
[0092] Furthermore, in accordance with another embodiment of the
present invention, the competing stimulus is a visual competing
stimulus included in the test pattern and the plurality of data
further includes data representing the position of the visual
competing stimulus within the test pattern.
[0093] Furthermore, in accordance with another embodiment of the
present invention, the step of processing includes determining for
at least one group of competing sensory stimuli having common
stimulus parameters the value of a competition grade, and
determining if the individual belongs to a group having a specific
clinical stage of the disease based on the determined value of the
competition grade.
[0094] Furthermore, in accordance with another embodiment of the
present invention, the wherein said competition grade represents
the efficiency of a group of competing sensory stimuli having
common stimulus parameters in preventing the tested individual from
reporting the presence of said difference of said perceived image,
when said difference is caused by said eye disease.
[0095] Furthermore, in accordance with another embodiment of the
present invention, the value of the competition grade is computed
as the percentage of projected test patterns for which the
individual reported at least one localized difference determined to
be caused by said eye disease between the perceived image of the
test pattern and the reference pattern, out of the total number of
projected test patterns for which the individual was subjected to
competing sensory stimuli belonging to a group of competing sensory
stimuli having common stimulus parameters.
[0096] Furthermore, in accordance with another embodiment of the
present invention, the test pattern is a segmented straight line,
the competing sensory stimulus includes one or more segments of the
segmented line which are shifted relative to the remaining segments
of the straight line to form an artificial distortion having a
defined amplitude. The position of the artificial distortion along
the segmented straight line varies in at least some repetitions of
the projecting of the test pattern, and within each group of
competing sensory stimuli having common stimulus parameters, the
amplitude of the artificial distortion is the same.
[0097] Furthermore, in accordance with another embodiment of the
present invention, the test pattern is a segmented straight line,
the competing sensory stimulus comprises one or more segments of
the segmented line which are shifted relative to the remaining
segments of the straight line to form an artificial distortion
having a defined amplitude. The at least one localized difference
is determined to be caused by the eye disease if the computed
distance between the center of the artificial distortion and the
position along the length of the segmented line at which the
individual reported the at least one localized difference exceeds a
preset value.
[0098] Furthermore, in accordance with another embodiment of the
present invention, the relationship of the first duration and the
second duration is selected from, the first duration is identical
to the second duration, the second duration precedes the first
duration, and the first duration at least partially overlaps with
the second duration.
[0099] There is also provided, in accordance with an embodiment of
the present invention, a method for obtaining data useful for
detecting eye disease in an individual. The method includes the
steps of:
[0100] fixating the individual's vision at or about a fixation
target projected at a first retinal location of the retina of an
eye of the individual;
[0101] projecting for a first duration a test pattern at a second
retinal location of the eye, to allow the individual to form a
perceived image of the test pattern;
[0102] receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected such a difference; and
[0103] repeating the steps of fixating, projecting and receiving a
number of times, such that for at least some of the repetitions of
the steps of fixating, projecting, and receiving, the individual is
subjected for a second duration to a competing sensory stimulus, to
obtain a plurality of data useful for detecting eye disease in the
individual.
[0104] There is also provided, in accordance with an embodiment of
the present invention, a system for detecting eye disease in an
individual, the system includes:
[0105] means for projecting patterns on the retina of an eye of the
individual;
[0106] means for fixating the individual's vision on a fixation
target projected on the retina;
[0107] means for providing input representative of the position of
a selected region of the retina at which a difference is observed
by the individual between a perceived image of one of the patterns
and a predetermined reference pattern;
[0108] means for controllably delivering to the individual
competing sensory stimuli; and
[0109] processing means operatively coupled to the means for
projecting, the means for fixating, the means for providing input
and the means for controllably delivering competing sensory
stimuli. The processing means is configured to perform the steps
of,
[0110] (a) projecting a first pattern at a first location on the
retina,
[0111] (b) determining when the individual's vision is fixated on
the fixation target,
[0112] (c) hiding at least a portion of the first pattern after the
individual's vision is fixated on the fixation target,
[0113] (d) projecting a second pattern at a second location on the
retina to allow the individual to form a perceived image of the
second pattern, and
[0114] (e) receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected such a difference;
[0115] (f) repeating steps (a) to (e) a number of times to obtain a
plurality of data, wherein in at least some of the repetitions of
steps (a) to (e), the individual is subjected to a competing
sensory stimulus.
[0116] Furthermore, in accordance with another embodiment of the
present invention, the system further includes means for storing
the plurality of data.
[0117] Furthermore, in accordance with another embodiment of the
present invention, the means for controllably delivering to the
individual competing sensory stimuli are selected from means for
delivering visual stimuli, means for delivering auditory stimuli,
means for delivering somatosensory stimuli, means for delivering
tactile stimuli, and means for delivering nociceptive stimuli.
[0118] Furthermore, in accordance with another embodiment of the
present invention, the processing means includes at least one
processing unit selected from a processor, a microprocessor, a
computer, a personal computer, a laptop computer, a controller, a
remote processor or computer, a server, a remote server, a
networked computer, and combinations thereof.
[0119] Furthermore, in accordance with another embodiment of the
present invention, the means for projecting is selected from a
display device, a beam scanning device, and a laser scanning
ophtalmoscope-like device.
[0120] Furthermore, in accordance with another embodiment of the
present invention, at least one of the means for fixating and means
for providing input comprises a device selected from the group
consisting of a pointing device, a computer input device, a
keyboard, a mouse, a light pen, a touch sensitive display device,
and combinations thereof.
[0121] Furthermore, in accordance with another embodiment of the
present invention, the means for projecting patterns is configured
for projecting test patterns and fixation targets on the
retina.
[0122] Furthermore, in accordance with another embodiment of the
present invention, at least one of the means for projecting, the
means for providing input and the means for fixating includes one
or more devices selected from a touch sensitive display device, a
pointing device, a light pen, joystick, a mouse, a keyboard, a
computer input device, and combinations thereof.
[0123] Furthermore, in accordance with another embodiment of the
present invention, the means for projecting, the means for fixating
and the means for providing input comprise a touch-sensitive
display device.
[0124] Furthermore, in accordance with another embodiment of the
present invention, the means for fixating comprises a device for
moving a cursor or a pattern projected by the means for
projecting.
[0125] Furthermore, in accordance with another embodiment of the
present invention, the means for fixating is selected from a
pointing device, a computer input device, a computer mouse, a
keyboard, a joystick, a light pen and a touch sensitive screen.
[0126] Furthermore, in accordance with another embodiment of the
present invention, the means for providing input comprises a
pointing device for operatively moving a cursor or a pattern
projected by the means for projecting.
[0127] Furthermore, in accordance with another embodiment of the
present invention, the processing means are configured to perform
the step of processing the plurality of data to determine if the
individual belongs to a group having a defined clinical stage of
the eye disease.
[0128] Furthermore, in accordance with another embodiment of the
present invention, the system also includes communication means for
communicating the plurality of data for processing outside of the
system.
[0129] Furthermore, in accordance with another embodiment of the
present invention, the system also includes communication means for
communicating with one or more devices outside of the system.
[0130] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimuli include visual
competing stimuli and the means for controllably delivering to the
individual competing sensory stimuli includes means for
controllably modifying the patterns projected on the retina.
[0131] Furthermore, in accordance with another embodiment of the
present invention, the system also includes means for providing
output to a user. The means for providing output is operatively
coupled to the processing means.
[0132] There is also provided, in accordance with an embodiment of
the present invention, a system for detecting eye disease in an
individual. The system includes:
[0133] a projecting unit for projecting test patterns and fixation
targets on the retina of an eye of the individual;
[0134] at least one input device for providing input representing a
difference observed by the individual between a perceived image of
one of the test patterns and a predetermined reference pattern;
[0135] a competing sensory stimuli generating unit for controllably
subjecting the individual to competing sensory stimuli; and
[0136] at least one processing unit operatively coupled to the
projecting unit, the at least one input device, and the competing
sensory stimuli generating unit. The at least one processing unit
is configured to perform the steps of,
[0137] (a) projecting a first pattern at a first location on the
retina,
[0138] (b) determining when the individual's vision is fixated on
the fixation target,
[0139] (c) hiding at least a portion of the first pattern after the
individual's vision is fixated on the fixation target,
[0140] (d) projecting a second pattern at a second location on the
retina to allow the individual to form a perceived image of the
second pattern,
[0141] (e) receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected such a difference, and
[0142] (f) repeating steps (a) to (e) a number of times to obtain a
plurality of data, wherein in at least some of the repetitions of
steps (a) to (e), the competing sensory stimuli generating unit
subjects the individual to a competing sensory stimulus.
[0143] Furthermore, in accordance with another embodiment of the
present invention, the system also includes a storage device for
storing the plurality of data.
[0144] Furthermore, in accordance with another embodiment of the
present invention, the projecting unit comprises the competing
sensory stimuli generating unit.
[0145] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimuli generating unit is
selected from a unit for delivering visual stimuli, a unit for
delivering auditory stimuli, a unit for delivering somatosensory
stimuli, a unit for delivering tactile stimuli, and a unit for
delivering nociceptive stimuli.
[0146] Furthermore, in accordance with another embodiment of the
present invention, the data is selected from, the presence of the
difference within the perceived image of the second pattern, the
approximate position within the perceived image of the difference,
the position of a second pattern relative to the fixation target,
the orientation of the second pattern on the retina, the presence
of a distortion in the second patterns, the position of the
distortion within the second pattern, the presence of a visually
perceivable difference between one or more parts of the perceived
image of the second pattern and the predefined reference pattern,
the position of the one or more parts within the perceived image,
one or more characteristics of the competing sensory stimuli, and
combinations thereof.
[0147] Furthermore, in accordance with another embodiment of the
present invention, the at least one processing unit is selected
from a processor, a microprocessor, a computer, a personal
computer, a laptop computer, a controller, a remote processor or
computer, a server, a remote server, a networked computer, and
combinations thereof.
[0148] Furthermore, in accordance with another embodiment of the
present invention, the projecting unit is selected from a display
device, a beam scanning device, and a laser scanning
ophtalmoscope-like device.
[0149] Furthermore, in accordance with another embodiment of the
present invention, the display device comprises a touch sensitive
display device.
[0150] Furthermore, in accordance with another embodiment of the
present invention, the at least one input device includes a device
selected from the group consisting of a pointing device, a computer
input device, a keyboard, a mouse, a light pen, a touch sensitive
display device, and combinations thereof.
[0151] Furthermore, in accordance with another embodiment of the
present invention, at least one of the projecting unit and the
input device includes one or more devices selected from a touch
sensitive display device, a pointing device, a light pen, joystick,
a mouse, a keyboard, a computer input device, and combinations
thereof.
[0152] Furthermore, in accordance with another embodiment of the
present invention, the system also includes communication means for
communicating with one or more devices outside of the system.
[0153] Furthermore, in accordance with another embodiment of the
present invention, the system also includes at least one output
device operatively coupled to the at least one processing unit for
providing output to a user.
[0154] There is also provided, in accordance with another
embodiment of the present invention, a system for detecting eye
disease in an individual. The system includes:
[0155] means for projecting test patterns and fixation targets on
the retina of an eye of the individual;
[0156] means for fixating the individual's vision on a fixation
target projected on the retina;
[0157] means for providing input representative of the position on
the retina at which a difference is observed by the individual
between a perceived image of one of the patterns and a
predetermined reference pattern;
[0158] means for controllably delivering to the individual
competing sensory stimuli; and
[0159] processing means operatively coupled to the means for
projecting, the means for fixating, the means for providing input,
and the means for controllably delivering to said individual
competing sensory stimuli. The processing means is configured to
perform the steps of fixating the individual's vision at or about a
fixation target projected at a first location of the retina,
projecting for a selected duration a test pattern at a second
location of the retina to allow the individual to form a perceived
image of the test pattern, receiving from the individual input
indicative of a difference in at least one localized part of the
perceived image of the step of projecting as compared to a
predefined reference pattern, if the individual detected such a
difference, and repeating the steps of fixating, projecting and
receiving a number of times to obtain a plurality of data, wherein
in at least some of the repetitions of the steps of fixating,
projecting and receiving, the individual is subjected to a
competing sensory stimulus.
[0160] Furthermore, in accordance with another embodiment of the
present invention, the processing means is configured for
performing the step of analyzing the plurality of data to determine
whether the individual has an eye disease.
[0161] Furthermore, in accordance with another embodiment of the
present invention, the system also includes means for storing the
plurality of data.
[0162] Furthermore, in accordance with another embodiment of the
present invention, the means for controllably delivering to the
individual competing sensory stimuli are selected from means for
delivering visual stimuli, means for delivering auditory stimulus,
means for delivering somatosensory stimuli, means for delivering
tactile stimuli, and means for delivering nociceptive stimuli.
[0163] Furthermore, in accordance with another embodiment of the
present invention, the processing means includes at least one
processing unit selected from a processor, a microprocessor, a
computer, a personal computer, a minicomputer, a laptop computer, a
controller, a remote processor or computer, a server, a remote
server, a networked computer, and combinations thereof.
[0164] Furthermore, in accordance with another embodiment of the
present invention, the means for projecting is selected from a
display device, a beam scanning device, and a laser scanning
ophtalmoscope-like device.
[0165] Furthermore, in accordance with another embodiment of the
present invention, at least one of the means for fixating and means
for providing input includes a device selected from the group
consisting of a pointing device, a computer input device, a
keyboard, a mouse, a graphic tablet, a light pen, a touch sensitive
screen, and combinations thereof.
[0166] Furthermore, in accordance with another embodiment of the
present invention, the means for fixating includes a device for
moving a cursor or a pattern projected by the means for
projecting.
[0167] Furthermore, in accordance with another embodiment of the
present invention, the system also includes communication means for
communicating with one or more devices outside of the system.
[0168] Furthermore, in accordance with another embodiment of the
present invention, the means for providing input includes a
pointing device for operatively moving a cursor or a pattern
projected by the means for projecting.
[0169] Furthermore, in accordance with another embodiment of the
present invention, the processing means are configured to perform
the step of processing the plurality of data to determine if the
individual belongs to a group having a defined clinical stage of
the eye disease.
[0170] Furthermore, in accordance with another embodiment of the
present invention, the competing sensory stimuli comprise visual
competing stimuli and the means for controllably delivering to said
individual competing sensory stimuli comprise means for
controllably modifying test patterns projected on the retina.
[0171] Furthermore, in accordance with another embodiment of the
present invention, the system also comprises means for providing
output to a user. The means for providing output is operatively
coupled to the processing means.
[0172] There is also provided, in accordance with another
embodiment of the present invention, a system for detecting eye
disease in an individual. The system includes:
[0173] a projecting unit for projecting test patterns and fixation
targets on the retina of an eye of the individual;
[0174] at least one input device for providing input representing a
difference observed by the individual between a perceived image of
one of the test patterns and a predetermined reference pattern;
[0175] a competing sensory stimuli generating unit for controllably
subjecting the individual to competing sensory stimuli; and
[0176] at least one processing unit operatively coupled to the
projecting unit, the at least one input device, and the competing
sensory stimuli generating unit. The at least one processing unit
is configured to perform the steps of,
[0177] fixating the individual's vision at or about a fixation
target projected at a first location of the retina,
[0178] projecting for a selected duration a test pattern at a
second location of the retina, to allow the individual to form a
perceived image of the test pattern,
[0179] receiving from the individual input indicative of a
difference in at least one localized part of the perceived image of
the step of projecting as compared to a predefined reference
pattern, if the individual detected such a difference, and
[0180] repeating the steps of fixating, projecting and receiving a
number of times to obtain a plurality of data, wherein in at least
some of the repetitions of the steps of fixating, projecting and
receiving, the individual is subjected to a competing sensory
stimulus.
[0181] Furthermore, in accordance with another embodiment of the
present invention, the system further includes a storage device for
storing the plurality of data.
[0182] Furthermore, in accordance with another embodiment of the
present invention, the projecting unit comprises said competing
sensory stimuli generating unit.
[0183] Furthermore, in accordance with another embodiment of the
present invention, the data is selected from, the presence of the
difference within the perceived image, the approximate position
within the perceived image of the difference, the position of the
test patterns relative to the fixation target, the orientation of
the test patterns on the retina, the presence of a distortion in
the test patterns, the position of the distortion within a test
pattern, the presence of a visually perceivable difference between
one or more parts of the perceived image and the predefined
reference pattern, the position of the one or more parts within the
perceived image, one or more characteristics of the competing
sensory stimuli, and combinations thereof.
[0184] Furthermore, in accordance with another embodiment of the
present invention, the processing unit is selected from a
processor, a microprocessor, a computer, a personal computer, a
laptop computer, a controller, a remote processor or computer, a
server, a remote server, a networked computer, and combinations
thereof.
[0185] Furthermore, in accordance with another embodiment of the
present invention, the projecting unit is selected from a display
device, a beam scanning device, and a laser scanning
ophtalmoscope-like device.
[0186] Furthermore, in accordance with another embodiment of the
present invention, the display device comprises a touch sensitive
display device.
[0187] Furthermore, in accordance with another embodiment of the
present invention, the at least one input device comprises a device
selected from the group consisting of a pointing device, a computer
input device, a keyboard, a mouse, a light pen, a touch sensitive
display device, and combinations thereof.
[0188] Furthermore, in accordance with another embodiment of the
present invention, at least one of the projecting unit and the
input device comprises one or more devices selected from a touch
sensitive display device, a pointing device, a light pen, joystick,
a mouse, a keyboard, a computer input device, and combinations
thereof.
[0189] Furthermore, in accordance with another embodiment of the
present invention, the system also includes communication means for
communicating with one or more devices outside of the system.
[0190] Furthermore, in accordance with another embodiment of the
present invention, the system also includes at least one output
device operatively coupled to the at least one processing unit for
providing output to a user.
[0191] There is also provided, in accordance with another
embodiment of the present invention, a program storage device
readable by machine, tangibly embodying a program of instructions
executable by the machine to perform method steps for detecting eye
disease in an individual. The program includes the steps of:
[0192] (a) projecting a first pattern on a first location on the
retina of an eye of the individual;
[0193] (b) fixating the individual's vision on a fixation target
projected on the retina at or about the first location;
[0194] (c) hiding at least a portion of the first pattern;
[0195] (d) projecting a second pattern on a second location of the
retina to allow the individual to form a perceived image of the
second pattern;
[0196] (e) receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected such a difference; and
[0197] (f) repeating steps (a) to (e) a number of times to obtain a
plurality of data, wherein in at least some of the repetitions of
steps (a) to (e), the individual is subjected to a competing
sensory stimulus.
[0198] Furthermore, in accordance with another embodiment of the
present invention, the repeating of step (f) is performed such that
in at least some of the repetitions of steps (a) to (e) the
location of projecting of at least the second pattern on the retina
is changed.
[0199] Furthermore, in accordance with another embodiment of the
present invention, the method steps of the program also include the
step of processing the plurality of data to determine if the
individual belongs to a group having a defined clinical stage of
the eye disease.
[0200] Furthermore, in accordance with another embodiment of the
present invention, the method steps of the program also include the
step of communicating the plurality of data to a device external to
the computer for processing the plurality of data to determine if
the individual belongs to a group having a defined clinical stage
of the eye disease.
[0201] There is also provided, in accordance with another
embodiment of the present invention, a computer program product
comprising a computer useable medium having computer readable
program code embodied therein for detecting eye disease in an
individual. The computer program product includes:
[0202] computer readable program code for causing a computer or a
projecting device operatively coupled to the computer to project a
first pattern on a first location on the retina of an eye of the
individual;
[0203] computer readable program code for causing the computer to
determine when the individual's vision is fixated on a fixation
target projected on the retina at or about the first location and
for hiding at least a portion of the first pattern when the
individual's vision is fixated on the fixation target;
[0204] computer readable program code for causing the computer to
project a second pattern at a second location of the retina to
allow the individual to form a perceived image of the second
pattern;
[0205] computer readable program code for causing the computer to
receive from said individual input indicative of a difference in at
least one localized part of the perceived image as compared to a
predefined reference pattern, if the individual detected such a
difference; and
[0206] computer readable program code for causing the computer to
perform a selected number of repetitions of the projecting of a
first pattern, the determining when the individual's vision is
fixated on the fixation target projected on the retina, the hiding
of at least a portion of the first pattern when the individual's
vision is fixated on the fixation target, the projecting of a
second pattern at a second location of the retina to allow the
individual to form a perceived image of the second pattern, and the
receiving from the individual of input indicative of a difference
in at least one localized part of the perceived image as compared
to the predefined reference pattern if the individual detected such
a difference, for obtaining a plurality of data, wherein in at
least some of the repetitions the individual is subjected to a
competing sensory stimulus.
[0207] Furthermore, in accordance with another embodiment of the
present invention, the computer readable program code further
includes computer readable program code for causing the computer to
process the plurality of data to determine whether the individual
has an eye disease.
[0208] Furthermore, in accordance with another embodiment of the
present invention, the computer readable program code further
includes computer readable program code for causing the computer to
communicate the plurality of data to a device external to the
computer for processing the plurality of data to detect the eye
disease.
[0209] Furthermore, in accordance with another embodiment of the
present invention, the computer readable program code further
includes computer readable program code for causing the computer to
change the location of projecting of at least the second pattern on
the retina in at least some of the repetitions.
[0210] There is also provided, in accordance with another
embodiment of the present invention, a program storage device
readable by machine, tangibly embodying a program of instructions
executable by the machine to perform method steps for detecting eye
disease in an individual. The method includes the steps of:
[0211] fixating the individual's vision at or about a fixation
target projected at a first retinal location of the retina of an
eye of the individual;
[0212] projecting for a first duration a test pattern at a second
retinal location of the eye, to allow the individual to form a
perceived image of the test pattern;
[0213] receiving from the individual input indicative of a
difference in at least one localized part of the perceived image as
compared to a predefined reference pattern, if the individual
detected such a difference; and
[0214] repeating the steps of fixating, projecting and receiving a
number of times to obtain a plurality of data, wherein for at least
some of the repetitions of the steps of fixating, projecting, and
receiving, the individual is subjected for a second duration to a
competing sensory stimulus.
[0215] Furthermore, in accordance with another embodiment of the
present invention, in at least some of the repetitions of the step
of repeating, the location of projecting of the test pattern on the
retina is changed.
[0216] Furthermore, in accordance with another embodiment of the
present invention, the method steps of the program also include the
step of processing the plurality of data to determine if the
individual belongs to a group having a defined clinical stage of
the eye disease.
[0217] Furthermore, in accordance with another embodiment of the
present invention, the method steps of the program also include the
step of communicating the plurality of data to a device external to
the computer for processing the plurality of data to determine if
the individual belongs to a group having a defined clinical stage
of the eye disease.
[0218] There is also provided, in accordance with another
embodiment of the present invention, a computer program product
comprising a computer useable medium having computer readable
program code embodied therein for detecting eye disease in an
individual. The computer program product includes:
[0219] computer readable program code for causing a computer or a
projecting device operatively coupled to the computer to project a
fixation target at a first retinal position of an eye of the
individual;
[0220] computer readable program code for causing the computer to
determine when the individual's vision is fixated at or about the
fixation target, and for projecting for a selected duration, when
the individual's vision is fixated on the fixation target, a test
pattern at a second retinal position of the eye, to allow the
individual to form a perceived image of the test pattern;
[0221] computer readable program code for causing the computer to
receive from the individual input indicative of a difference in at
least one localized part of the perceived image as compared to a
predefined reference pattern, if the individual detected such a
difference; and
[0222] computer readable program code for causing the computer to
perform a selected number of repetitions of the projecting of the
test pattern, the determining when the individual's vision is
fixated at or about the fixation target, the projecting of a test
pattern at the second location, and the receiving of the input from
the individual if the individual detected such a difference, for
obtaining a plurality of data, wherein in at least some of the
repetitions the individual is subjected to a competing sensory
stimulus.
[0223] Furthermore, in accordance with another embodiment of the
present invention, the computer readable program code further
includes computer readable program code for causing the computer to
change the location of projecting of the test pattern on the retina
in at least some of the repetitions.
[0224] Furthermore, in accordance with another embodiment of the
present invention, the computer readable program code further
includes computer readable program code for causing the computer to
process the plurality of data to determine whether the individual
has an eye disease.
[0225] Finally, in accordance with another embodiment of the
present invention, the computer readable program code also includes
computer readable program code for causing the computer to
communicate the plurality of data to a device external to the
computer for processing the plurality of data to detect the eye
disease.
BRIEF DESCRIPTION OF THE DRAWINGS
[0226] The invention is herein described, by way of example only,
with reference to the accompanying drawings, in which like
components are designated by like reference numerals, wherein:
[0227] FIG. 1 is a schematic diagram illustrating a system for
carrying out an eye test to detect an eye disease according to one
embodiment of the invention;
[0228] FIG. 2 is a schematic flow chart diagram illustrating a
method of executing an eye test for detecting an eye disease using
a system such as the system illustrated in FIG. 1, in accordance
with an embodiment of the present invention;
[0229] FIG. 3 schematically illustrates selected exemplary screen
representations including exemplary test patterns which may be
presented to a tested subject, in an exemplary embodiment of the
testing method of the present invention, and selected schematic
representations of how the test patterns may be perceived by a
tested subject in selected stages of the testing;
[0230] FIGS. 4A-4B are schematic diagrams illustrating some
exemplary types of line series which may be useful for mapping
retinal and/or choroidal lesions in accordance with some exemplary
embodiments of the present invention;
[0231] FIGS. 5A-5J are schematic diagrams illustrating patterns
displayed at various different exemplary steps of another
embodiment of an eye test performed by the system illustrated in
FIG. 1, and the possible appearance of the test patterns as they
may be perceived by the test subject at some exemplary steps of the
eye test;
[0232] FIG. 6 is a schematic diagram useful in understanding an
exemplary positioning accuracy criterion which may be used in the
eye testing method, in accordance with one exemplary embodiment of
the present invention;
[0233] FIGS. 7A and 7B are schematic diagrams useful in
understanding exemplary proximity criteria which may be used in
exemplary embodiments of the present invention;
[0234] FIG. 8 is a schematic flow diagram useful in understanding a
method for performing a test session and analyzing the results of
the test session, in accordance with one possible embodiment of the
present invention;
[0235] FIG. 9 is a bar graph representing experimental results
comparing the performance of the standard Amsler grid test with the
performance of the eye test of the present invention;
[0236] FIG. 10 is a schematic diagram illustrating a system
including a scanning laser device or another eye scanning device
usable for carrying out an eye test according to another preferred
embodiment of the invention;
[0237] FIG. 11 is a diagram schematically illustrating four
different possible response types of the same patient when the
patient is presented with a test pattern including an artificial
distortion, such that part of the projected image of the test
pattern falls on a retinal or choroidal lesion in the patient's
retina;
[0238] FIG. 12 is a schematic diagram illustrating in detail part
of a schematic artificially distorted test pattern used in the
competition experiments performed in accordance with an embodiment
of the present invention;
[0239] FIGS. 13 and 14 are schematic diagrams illustrating in
detail the criterion for determining if a position marked by the
patient is due to a pathology related observed distortion (PROD)
indicating the presence of a retinal or choroidal lesion or due to
an artificially induced observed distortion (AIOD) indicating the
observation of an artificial distortion, in accordance with one
embodiment of the present invention;
[0240] FIG. 15 is a schematic diagram illustrating is a schematic
diagram illustrating a system for carrying out an eye test to
detect and or assess an eye disease using auditory competing
stimuli in accordance with another embodiment of the present
invention;
[0241] FIG. 16 is a schematic block diagram illustrating a system
for applying visual tests and competing sensory stimuli to a test
subject, in accordance with an embodiment of the present invention;
and
[0242] FIGS. 17A-17J are schematic diagrams illustrating exemplary
forms of various different test patterns and competing visual
stimuli which may be used in accordance with some embodiments of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0243] The following terms are used throughout the application:
1 Term Definition AD Artificial distortion AIOD Artificially
induced observed distortion AMD Age-related macular degeneration
CNV Choroidal Neovascularization CS Competing stimulus DVS
Distracting visual stimulus GA Geographic atrophy HRC High risk
characteristics LAN Local area network MCPT Macular computerized
psychophysical test PAN Private area network PDT Photodynamic
Therapy PROD Pathology related observed distortion PSTN Public
service telephone network RPE Retinal pigment epithelium SLO
Scanning Laser Ophtalmoscope TTT Trans-pupilary Thermotherapy VPN
Virtual private network WAN Wide area network
[0244] It is noted that the test or tests for eye disease of the
present invention disclosed hereinbelow may also be generally
referred to as the Macular computerized psychophysical test (MCPT)
hereinafter.
[0245] FIG. 1 is a schematic diagram illustrating a system for
carrying out an eye test to detect an eye disease according to one
embodiment of the invention. A subject 100 performs an eye test
using a computer system 105. The computer system 105 may comprise a
computer 110, a display device 115 having a screen 112 and one or
more computer input devices such as a keyboard 120 or a computer
mouse 125. The computer system 105 may communicate over a
communication network schematically indicated by the cloud labeled
130. The network 130 may be, for example, the Internet, a local
area network (LAN), a wide area network (WAN), an Intranet, a
private area network (PAN), the public service telephone network
(PSTN), virtual networks implemented over the Internet, other
private and/or commercial communication networks, or any other
suitable type of communication network known in the art.
[0246] A processor 135 in a network server 140 stores data relating
to execution of an eye test to be performed by the subject 100 to
be described in detail below. The eye test is communicated from the
server 140 to the subject's computer 110 over the network 130. The
subject 100 inputs responses to the eye test using one or more of
the computer input devices such as the keyboard 120 or the mouse
125. The subject's responses are communicated over the network 130
to the processor 135, and stored in the memory 145. The processor
135 is configured to analyze the subject's response, to make a
diagnosis of the subject's conditions and to recommend future
follow-up or recommend prompt examination, all in real time, for
the subject.
[0247] The diagnosis and recommendation may be communicated over
the network 130 to the subject's computer system 105 and/or to a
terminal 150 of a health care provider 155. The processor 135 is
also configured to store in the memory 145 dates on which the
subject is to perform an eye test executed by the processor 135.
If, for example, the subject 100 has been instructed by the health
care provider 155 to perform the test once per week, the processor
135 may send a message over the communication network 130 when 10
days have elapsed since the last time he took the test, informing
the subject of his failure to take the test as instructed. A
similar message may be sent to the health care provider 155. A
responsible individual may be designated, in such a case, to
contact the subject 100, for example, by telephone to clarify why
the subject 100 has not performed the test as instructed and to
impress upon the subject the importance of performing the test as
indicated.
[0248] "Moving Pattern" Test Method
[0249] The method disclosed hereinbelow is based on the
presentation of a first pattern at a first location on the surface
of a display device (such as, but not limited to the screen 112 of
the display device 115) to the patient or the test subject. After
the patient fixated on a fixation target presented on or adjacent
to the first pattern, the first pattern disappears from the first
location of the display device and a second pattern is presented at
a second location on the display device. The second pattern may be
identical to the first pattern (except for the fact that it appears
at a different location on the display device) or it may be
different from the first pattern by having one or more portions
thereof changed or altered, or, preferably, transiently changed or
transiently altered.
[0250] Such changes or transient changes or alterations may include
distortion of the shape or elimination of one or more portions of
the first pattern, or changes in the color or appearance of one or
more portions of the first pattern. Because the first pattern is
made to disappear from the first location on the display device and
the second pattern appears at a second location of the display
device different than the first location, the patient or test
subject may visually perceive this as a movement or jump of the
pattern from the first location to the second location on the
display device. In other words, the patient may perceive a pattern
"jumping" on the screen of the display device from a first to a
second location even though the pattern does not actually move on
the display device (the pattern actually disappears from a first
location on the display device and appears at a second location on
the display device). This is why this particular embodiment of the
testing method is referred to as the "moving pattern" or "jumping
pattern" test hereinafter.
[0251] FIG. 2 is a schematic flow chart diagram illustrating a
method of executing an eye test for detecting an eye disease using
a system such as the system illustrated in FIG. 1, in accordance
with an embodiment of the present invention.
[0252] FIG. 3 schematically illustrates selected exemplary screen
representations including exemplary test patterns which may be
presented to a tested subject, in an exemplary embodiment of the
testing method of the present invention, and selected schematic
representations of how the test patterns may be perceived by a
tested subject in selected stages of the testing.
[0253] FIG. 3 includes schematic screen diagrams 300, 320, 330 and
360 (also referred to as screens 300, 320, 330 and 360 hereinafter)
which schematically illustrate the patterns displayed on the screen
112 of the subject's display device 115 at various different
exemplary steps of the eye test performed by the system illustrated
in FIG. 2, and schematic screen diagrams 340 and 350 (also referred
to as screens 340 and 350 hereinafter) which schematically
illustrate the possible appearance of the screen 112 as may be
perceived by the tested subject at some exemplary steps of the eye
test. It is noted that screen 300 of FIG. 3 which does not include
test patterns, schematically represents a possible log-on screen
which may be presented to the test subject.
[0254] It is noted that the exemplary schematic screens 300, 320,
330, 340, 350, and 360 of FIG. 3 are schematically drawn for
illustrative purposes only and are not drawn to scale.
Additionally, the sizes of the various patterns, pattern segments
and fixation targets are not drawn to scale, and their sizes and
their relation to the screen size are arbitrarily shown for
illustrative purposes only.
[0255] Turning to FIG. 2, in step 200, the subject 100 may log onto
the computer system 105. The processor 135 may cause log-on screen
300 to be displayed on the subject's display device 115 (step 205).
The log-on screen 300 prompts the subject to input his name into a
field 302 and to input a previously assigned password into a field
304 for accessing the processor 135. In step 210 the subject inputs
his name and password using computer input devices such as the
keyboard 120 or the mouse 125. The processor 135 then checks
whether the inputted name and password are stored in the memory 145
(step 215). If the inputted name and password do not match a
corresponding name and password which are stored in the memory 145,
the processor 135 determines whether the number of attempts the
subject has made to input a name and password is less than a
predetermined number of attempts such as, for example, three
attempts (step 220). If yes, the process returns to step 205. If
no, the process terminates.
[0256] If at step 215 the processor determines that the name and
password are in the memory 145, the process continues in step 248
by the subject being instructed to cover an eye, so that the test
is performed using one eye only. The subject may be instructed to
cover an eye by displaying appropriate text (not shown) or a
drawing (not shown) or an icon (not shown), or a graphic element
(not shown) or any combination thereof on the screen of the display
device 115.
[0257] It is noted that the tested subject 100 may be asked to
cover a specific eye (for example, the subject may be asked to
cover the right eye and to view the screen 112 with the uncovered
left eye for testing the left eye). In this way the computer system
110 may automatically record that the left eye is being tested.
However, the test may also be performed with both eyes open as a
selected eye is being tested. Alternatively, the tested subject 100
may be asked to mark or input or otherwise indicate which eye is to
be tested, such as, for example, by clicking a cursor on one of two
boxes (not shown) which may be presented on the log-on screen 300
or on any other suitable screen presented to the subject before the
test begins. In such a case the test results may be labeled as
taken from the eye selected by the subject 100.
[0258] In step 250 a form screen 320 is displayed in which a
pattern, such as the segmented line 322, is displayed. This is by
way of example only, and other suitable patterns may be used within
the scope of the invention. The pattern may comprise a single
component, or may comprise several components, which may or may not
be all identical. Thus, the pattern may comprise several lines, one
or more circles, lines and circles together, or any other suitable
combination of pattern elements, including but not limited to one
or more straight lines, dotted lines, curved lines, linear or non
linear segments, dots, and other various geometrical patterns such
as but not limited to circles, arcs, rectangles, squares, triangles
and the like. The screen 112 of the display device 115 may display
a visually noisy background to the displayed pattern. The line 322
may be composed of several short segments 229 separated by gaps
227. Alternatively, the displayed line may be continuous (not
shown).
[0259] Preferably, the length of the line 322 is such that when the
tested subject's eye is at a distance of approximately 50
centimeter from the screen 112 of the display device 115, the
length of the line 322 corresponds to a cone angle of 1-20.degree..
It is, however, noted that other different cone angles and other
different viewing distances (smaller or larger than 50 centimeters
from the screen 112) may be used. Additionally, it may be possible,
in accordance with other embodiments of the invention, to use
"virtual reality" goggles worn by the patient which may have
different screen sizes and may be disposed at a different distance
from the patient eye.
[0260] It is noted that while in most tests the length of the lines
used corresponded to a cone angle of 14.degree., other different
line lengths may be used. At these viewing conditions, each of the
gaps 227 between the segments 229 (the distances separating two
adjacent segments 229) may correspond to a cone angle of between 1
minutes arc to about 2.degree. (two degrees). Other different line
lengths and gap sizes may however also be used. For example, if the
test pattern is a continuous line there are no gaps.
[0261] It is also noted that if test patterns which comprise a
continuous line are used, no segments are used and there are
therefore no gaps.
[0262] If the pattern includes two or more parallel lines, the
spacing between the lines corresponds, preferably, to a cone angle
from about 10 to about 600 minutes arc. The test patterns may be
horizontal patterns such as, but not limited to, the horizontal
line 322 illustrated in screen 300, but may also be vertical
patterns such as but not limited to a vertical segmented line (not
shown) or slanted patterns such as, but not limited to, a slanted
segmented line (not shown). A fixation target 228 may be displayed
on the screen adjacent to one of the segments 229. The fixation
target may be a circular pattern such as the circular fixation
target 228 of screen 320 of FIG. 3, or may have any other shape or
pattern suitable for serving as a fixation target to focus the
tested eye thereon, such as, but not limited to, a square pattern,
a triangular pattern, or any other suitable pattern which is
suitable for functioning as a fixation target.
[0263] It is noted that while the fixation target 228 illustrated
in FIG. 3 is a circular pattern which appears close to the middle
segment of the line 322, other different forms of the fixation
target may be used. For example, the fixation target may be
implemented as a hollow (unfilled) circle (not shown) surrounding
the middle segment of the line 322 or superimposed thereon, or as
any other suitable pattern which is positioned close to or is
superimposed upon the line 322.
[0264] Generally, the shape of the fixation target may depend,
inter alia, on the shape and dimensions of the test pattern which
is being used in the test. The fixation target may have the same
color of the test pattern (such as, for example, the segmented line
322) or may have a different color than the color of the test
pattern. In accordance with another variation, the fixation target
may be the central (middle) segment of the line 322, in which case
the middle segment may or may not have a color which is different
than the color of the remaining segments 229 of the line 322, in
order to make it easily identifiable by the test subject.
[0265] In the example in which a single segmented line serves as
the test pattern, the subject may be instructed to bring a cursor
225 appearing on the screen to the fixation target 228. In order to
aid the subject, the movement of the cursor 225 may be restricted
to a line (not shown) which is parallel to the line 322 so that the
cursor 225 always points to one of the segments 229.
[0266] The subject 100 may be asked (for example, by an instructor,
a physician an ophtalmologist or any other person training the
subject in performing the test) or otherwise instructed (such as
for example by displaying appropriate messages or text an the
screen 112 of the display device 115) to point the cursor 225 at
the fixation target 228. The subject 100 may perform this pointing
in step 255 by using a computer device such as the keyboard 120, or
more preferably the mouse 125. Other pointing devices may also be
used for pointing, such as but not limited to, a keypad, a
digitizing tablet in conjunction with a stylus, or a finger, a
light pen in conjunction with a touch sensitive screen or a touch
sensitive display device, a joystick or any other suitable pointing
device or suitable input device or computer input device known in
the art.
[0267] The fixation target 228 may be sized so that it is large
enough to be seen by the patient or test subject, but small enough
so that bringing the cursor 225 to the fixation target 228 is a
demanding task for the test subject. This causes the subject to
fixate his vision on the fixation target 228. Upon bringing the
cursor to the segment 229, the subject may provide a suitable
indication that he has positioned the cursor 225 to point at the
fixation target 228. For example, the patient or test subject 100
may provide the indication by clicking on the mouse 125 or by
depressing a predetermined key on the keyboard 120 (step 260). This
input may serve as an indication or a verification that visual
fixation has been achieved. It is noted that the size of the
fixation target 228 may depend, inter alia, on the distance of the
tested eye from the screen 112.
[0268] It is noted that if the subject is using a pointing device
and/or an input device which is different than the mouse 125 or the
keyboard 120, the subject may indicate fixation on the fixation
target 228 by performing any other suitable action. For example, if
a touch screen (not shown) is used as an input device, the subject
may touch the touch screen (not shown) with a light pen (not
shown), or with a stylus (not shown) or with a finger (not shown)
at the position at which the fixation target is displayed. Other
suitable forms of indicating or confirming fixation may be used,
depending, inter alia, on the input device or pointing device which
is being used.
[0269] When the subject signals (for example, by clicking a button
on the mouse 125, or by any other suitable way) that the cursor 225
is positioned to point at the fixation target 228, indicating that
his vision is fixated on the fixation target 228, the line 322 is
made to disappear from the screen 320 (step 265). After a
predetermined delay time interval (for example a delay interval in
the range of 0 to 200 milliseconds), a second pattern such as the
segmented line 332 is made to appear (displayed) on the screen 112
at a location different than the location of the line 322 as shown
in screen 330 (step 270), so as to allow the subject to form a
perceived image of the segmented line 332. In this example, the
segmented line 332 is similar to the line 322 but appears on the
screen 112 at a location which is different than the location of
the line 322.
[0270] It is noted that if the duration of the delay time interval
is zero, the line 332 is presented on the screen 112 immediately
after (or within the short time required by the computer 100 to
process the subject's input and display the line 332 on the screen
112) the subject 100 indicated fixation. In most of the
experimental eye tests conducted in patients no delay was used (the
delay time interval was zero).
[0271] The line 332 may, for example, be parallel to the line 322.
Since the subject's vision had been fixated on the fixation target
228, the line 332 will appear in the periphery of the subject's
field of vision. Any disturbance in his vision due to a retinal or
choroidal lesion (such as but not limited to a lesion caused by AMD
or diabetes or by other different pathological eye conditions) may
be apparent to the test subject as a difference between the
perceived image of the second pattern and a pre-defined reference
pattern, which in this example is provided by the first pattern
(the segmented straight line 322).
[0272] Additionally, or alternatively, the tested patient or
subject 100 may have been told by a trainer (such as, for example,
by an ophtalmologist or other medical or paramedical personnel)
before the beginning of the test that he or she is going to be
presented with test patterns which will look like a segmented
straight line. In such a case, the subject 100 may conceive a
"virtual" predetermined reference pattern which in this particular
example of the test is a conceived image of a straight segmented
line. The word "virtual" is used herein to indicate that the
predetermined reference pattern is mentally conceived by the
patient or test subject without having to actually present the
patient with the test pattern. In other words, the understanding of
the patient of how the reference pattern (such as, for example, the
straight segmented line of the example illustrated in FIG. 3) is
supposed to look like may be based on the previous visual
experience of the patient or test subject.
[0273] The explanation to the patient of what the reference pattern
is going to look like may be advantageous, since in a small
percentage of patients it may happen that in the first presentation
of the first test pattern (such as for example in the initial
presentation of the line 322) the image of the test pattern may
fall on a lesioned retinal or choroidal region. In such a case, the
perceived image of the test pattern may be distorted. Therefore, in
such a case, the perceived image of the initially presented line
322 is not usable as a reference pattern and the patient may see or
detect a difference between the perceived image of the line 322 and
the (virtual) reference image which the patient has been told to
expect.
[0274] The difference between the perceived image of any of the
test patterns (including, but not limited to, the lines 322 and
332) which may be presented to the patient and the reference
pattern may be perceived by the test subject 100 in various
different ways. Thus, as the line 322 is perceived by the subject
to jump or move to the new location on the screen 112 one or more
of the segments 229 of the line may seem to the subject not to
arrive at their new position on the line 332 (of the screen 330) at
exactly the same pace or contour as the other segments. In other
words, one or more portions or segments of the line may temporarily
seem to lag or to move differently relative to the other parts or
segments of the perceived line. This may also be perceived by the
subject as if one or more portions of the perceived line were wavy
or moved or bulged for a short while or as if one or more of the
segments or line portions deviated from the reference pattern
(which is a straight segmented line, in the exemplary and
non-limiting example of FIG. 3) before assuming again the perceived
appearance of the reference pattern. Additionally or alternatively,
depending, inter alia, on the nature of the retinal (or choroidal)
lesion present, one or more portions or segments of the perceived
image of the test pattern (such as, for example, one or more of the
segments 229 of the perceived line 322) may appear to temporarily
change their apparent brightness (such as becoming brighter or
becoming darker), or change their color temporarily as the line
moves or jumps, and then return to their originally perceived
brightness or originally perceived color, respectively.
Additionally or alternatively, one or more of the segments 229 or
portions of the test pattern may appear to momentarily or
temporarily become blurred or smeared.
[0275] Additionally, various different combinations of these
differences may also be perceived by the subject. For example one
or more of the segments or portions of the test pattern may appear
to lag or move differently than the other segments or portions of
the pattern and also to change their perceived brightness. Other
different combinations of differences may also be perceived by some
patients.
[0276] For example, when the subject's vision is fixated at the
location where the fixation target 228 had previously appeared
(represented by the crossed lines 342 in screen 340), a segment 344
of the line 332 may appear to be out of line with other segments in
the line 332 or may be otherwise distorted, blurred, shifted or
discolored. It is noted that the screen labeled 340 of FIG. 3
represents the screen 112 and the pattern 332 as perceived by the
tested subject. In other words, the illustrated line 332 with the
shifted segment 344 is shown as perceived by a subject or patient
having a retinal or choroidal lesion and not as actually displayed
on the screen 112. Thus, while the screen 330 of FIG. 3
schematically represents the image as actually presented to the
subject 105 on the screen 112, the screen 340 of FIG. 3 represents
the image perceived by a subject having a retinal or choroidal
lesion (in the tested eye) after the line 332 of screen 320 is made
to disappear (hidden) and the line 332 of screen 330 is presented
(or displayed) to the subject at a different location on the screen
112.
[0277] Screen 340 (of FIG. 3) illustrates a possible appearance of
the line 332 (of screen 330) to an individual having a retinal or
choroidal lesion. The perceived line 352 of the perceived screen
340 represents the image of the line 332 presented in screen 330 as
it may be perceived by an individual having a retinal or choroidal
lesion. The segment 342 of the perceived line 352 may typically be
temporarily or transiently perceived as being out of line with
other segments in the line 352. This is by way of example only, and
other differences between the perceived image and the pre-defined
reference pattern may be perceived, such as, but not limited to,
one or more segments in the second pattern appearing to the subject
as being shifted or wavy or lagging behind, or blurred, or dimming,
or smeared, or bent, or otherwise distorted, or discolored.
Additionally, one or more of the segments in the second pattern may
be perceived by the subject to disappear or to be missing from the
second pattern. As the subject subsequently shifts his vision from
the fixation target 228 to the presented line 332, the segment 344
in the image of the perceived line 352 may appear to move into
alignment with other segments in the line 332 as shown in screen
350. Thus, the line 363 of screen 350 (FIG. 3) schematically
represents the perceived image of the line 322 as possibly
perceived by the subject having a retinal or choroidal lesion after
the subject re-fixates his vision on the line 332. Thus, the
segment 344A schematically represents the new perceived position of
the previously perceived segment 344 after the patient shifted his
eye to refixate on the new position of the line 332. The perceived
segment 344A may now be perceived as realigned again with the rest
of the perceived segments of the perceived line 363.
[0278] Typically, the reason for the presented line 332 being
perceived as straight again (as illustrated in the perceived line
363 of screen 350) after the patient refixated his vision at the
new position at which the line 332 appeared after the line 322
disappeared from the screen, is that in most cases when the subject
shifts his vision from the fixation point 228 to the new location
on the screen at which the line 332 appeared, after a certain time
(typically a few hundred milliseconds or longer) the "filling-in"
phenomenon disclosed hereinabove may occur.
[0279] The subject, in step 275, may indicate which, if any, of the
segments in the line 332 appeared different or were perceived to
behave differently than corresponding segments in the predefined
reference pattern. This may be done by the subject bringing the
cursor 225 to the segment or segments that appeared to move or to
blur or to distort or to disappear, or to otherwise change (the
segment 344 in this example) and clicking a button on the mouse 125
or a key on the keyboard 120, or by otherwise performing an action
with a pointing device (not shown) or any other suitable input
device (such as, but not limited to, any of the input devices
disclosed hereinabove and hereinafter). The data representing the
location(s) on the screen 112 of the segment or segments in the
region pointed to by the subject may thus be stored by the system
(step 277) in the memory of the computer system 105, and/or in the
memory 145 of the server 140 or by any other suitable storage
means, such as but not limited to, a fixed or removable magnetic
media storage device (Hard disc drive or floppy disc drive),
optical storage device, magneto-optical storage device, holographic
storage device or any other suitable storage device known in the
art. This stored data may be used to locate and/or report and/or
display and/or symbolically represent (in hard copy or otherwise),
the region in the subject's retina in which the retinal lesion (or
an underlying choroidal lesion) is located, as disclosed in detail
hereinafter.
[0280] It is noted that the storage device or memory used for
storing the test results data may be included in or suitably linked
or coupled to the computer system 105 or the computer 110, or the
server 140. Alternatively, the storage device may be a shared
device which is shared by or accessible to one or more of the
computer system 105 or the computer 110, or the server 140, over a
communication network. Thus, while the test results data may be
stored locally on the system 105, this is not obligatory and the
test results may be stored elsewhere as disclosed hereinabove.
[0281] In step 280 it is determined whether adequate mapping of the
field of vision was achieved. For example, it may be checked
whether the number of lines 322 presented to the subject is less
than a predetermined number, such as, for example, 40 (or any other
suitable predetermined number). If the number of lines 322
presented to the subject is less than the predetermined number, the
process may return to step 250 and a new line 322 is presented to
the subject. Steps 250 to 280 may be repeated several times, for
example 40 times (or any other suitable predetermined number of
times suitable for such a test). In each repetition the line 332
may be presented at a different location of the screen 112 until
the region of the subject's macular visual field has been
appropriately mapped.
[0282] It is noted that such mapping may be achieved in more than
one way. For example, in accordance with one preferred embodiment
of the invention, after the line 332 is presented or displayed to
the subject 100, and the subject has finished marking the segments
which appeared different than the corresponding segments of the
line 322, or alternatively to mark the segments which appeared
different than the "virtual" predetermined reference pattern (a
straight segmented line mentally conceived by the subject), the
subject may visually fixate the tested eye on a fixation target
228A (see screens 330, 340, 350 and 360) in the vicinity of the
line 332, by bringing the cursor 225 to point at the fixation
target 228A and clicking a button on the mouse 125 to indicate
fixation as disclosed in detail hereinabove. This may trigger the
repeating of steps 265 and 270 which will result in the
disappearing of the line 322 and the showing of a new line (not
shown) at a new position on the screen 112 which is different than
the position at which the line 332 was previously presented. The
subject may then proceed to mark any segments at which a difference
was perceived as disclosed hereinabove. The presentation may be
similarly continued until adequate mapping of the field of vision
has been performed.
[0283] Alternatively, in accordance with another embodiment of the
present invention, after the line 332 is presented or displayed to
the subject 100, and the subject has finished marking the segments
which appeared different than the corresponding segments of the
line 322, or alternatively to mark the segments which appeared
different than the "virtual" predetermined reference pattern (a
straight segmented line mentally conceived by the subject), the
line 332 may be caused to disappear from the screen 112, and the
line 322 and the fixation target 228 may be again presented to the
subject 110 in the same positions illustrated in screen 320. The
subject may then again fixate on the fixation target 228 by
bringing the cursor 225 to point at the fixation target 228 and
click the mouse 125 to indicate fixation. The computer 100 may then
present a new test pattern (not shown) at another new position
relative to the position of the line 322 and the process may repeat
after the subject marked any segments for which a difference was
observed. By randomly or pseudo-randomly selecting a new line
position for each new repetition the process may thus achieve
adequate mapping of the desired macular area.
[0284] It is noted that if the first test pattern (such as for
example the straight segmented line 322) which is presented to the
subject happens to be projected on a region of the retina which is
lesioned (at the retinal or the choroidal level), the subject 100
may initially perceive the pattern to be distorted or modified but
after a certain time the test pattern may be perceived to be
identical with the predetermined reference pattern (such as for
example a straight non-distorted segmented line due to the "filing
in" phenomenon disclosed hereinabove. In such a case, the subject
100 may indicate or mark the location of the initially perceived
distorted or modified region or component of the first test
pattern, by using the mouse 125 and the cursor 225 as disclosed
hereinabove.
[0285] Alternatively, the subject 100 may be instructed (before or
during the test) to ignore the initially perceived distortion or
modification and to proceed to perform the fixation on the fixation
target 228 as disclosed hereinabove by bringing the cursor 225 to
point at the fixation target 228 and clicking a button on the mouse
125. When the second test pattern, such as the line 332 is then
presented at another location on the screen 112 (see screen 330 of
FIG. 3), the subject 100 may temporarily perceive a modification or
distortion as the subject 100 shifts his vision from the fixation
target towards the location of newly presented test pattern (which
in this example is the location of the line 332 of screen 330 of
FIG. 3). Therefore, in such cases in which the image of the first
test pattern falls on a lesioned retinal area, the subject may
perceive a distortion or modification in each of the repetitions or
iterations of the test, irrespective of the location at which the
second test pattern is presented on the screen 112. The distortion
will be perceived after the patient shifted his vision from the
fixation target towards the test pattern presented at the new
location due to the fact that the shifting causes the image of the
newly presented test pattern to be projected on the lesioned
retinal area. Because of this phenomenon, the subject may mark a
distortion or modification on all the second test pattern
repetitions, and all of the marked distortions will tend to be
marked at positions along the test pattern which approximately
correspond to the position of the distortion or modification which
was initially perceived at the first time of presentation of the
first test pattern due to the presence of the retinal lesion (or of
a choroidal lesion).
[0286] It is noted that if the test results do exhibit such an
approximate "alignment" of multiple markings of perceived
distortions or modifications at approximately similar positions on
the test pattern, irrespective of the location of the presented
second test patterns, this may be taken as an indication that there
is at least one suspected retinal (or choroidal) lesion at a
position in the retina on which the image of first test pattern was
projected.
[0287] It is further noted that while the presence of a retinal
lesion may be detected in the above case, it may be advisable to
test the same eye of subjects exhibiting such a spurious marking
"alignment" using the "flash test" embodiment of the invention as
disclosed in detail hereinafter, since this test does not show this
spurious marking "alignment" phenomenon.
[0288] It is noted that while it is possible to perform the testing
by mapping the field of view of the patient using only horizontal
line patterns (such as the line 322) and moving the horizontal line
patterns vertically to different positions on the screen 112, the
mapping may also be performed using vertical lines (not shown in
FIG. 3) which may be moved horizontally to different positions on
the screen 112. It may also be possible to use a plurality of
orthogonal horizontal and vertical lines in the same mapping test,
in which case the mapping coverage of the field of vision may
resemble a grid of intersecting lines (not shown).
[0289] Furthermore, the mapping of the field of view may also be
done using a series of lines that are inclined at an angle to the
horizontal or vertical orientation (slanted lines), or combination
of series of slanted lines which may intersect each other either
orthogonally or non-orthogonally, such that if these lines were all
displayed at the same time on the screen 112 they may form a grid
of intersecting lines (not shown).
[0290] It is noted that in step 280 it is checked whether adequate
mapping of the field of vision of the tested eye has been achieved.
For example, if the location of presentation of the test pattern is
different at each repetition or iteration of the test, adequate
mapping may be ensured by checking that the number of lines
presented to the subject has reached a predetermined number of
iterations ensuring that data has been collected which suitably
covers or maps the entire field of vision at a desired
resolution.
[0291] Other different methods may however also be used to check
adequate mapping. For example, if the testing of each location
needs to be repeated more than one time and the location of
presentation of test patterns is randomly or pseudo-randomly
selected, the locations of performed tests may be compared with a
look-up table to verify that the desired number of test repetitions
for each test pattern location has been performed. If adequate
mapping has not been achieved the process may return control to
step 250 to present the next test pattern.
[0292] If adequate mapping of the field of vision of an eye has
been achieved, the process may proceed by determining whether only
one eye has been examined so far (step 282). If only one eye has
been examined, the subject may be instructed to uncover the
non-examined eye and to cover the examined eye (285). The process
may then return to step 250 with the subject testing his other eye
as disclosed in detail hereinabove. If both eyes have been
examined, the process may terminate (step 290).
[0293] The position of the line 322 presented or displayed to the
subject on the screen 112 may thus be varied in order to
appropriately cover the macular area at a desired resolution so as
to detect lesioned retinal regions. It is noted that in accordance
with one preferred embodiment of the invention, the mapping may be
performed more than once, and that the central part or foveal
region of the macular area of the retina may also be mapped at a
higher resolution than the rest of the macular area. This may be
accomplished by presenting to the subject test patterns such as the
line 322 at locations which are relatively close to one another on
the screen 112. This may result in higher lesion mapping resolution
in the foveal region. In addition, more test patterns may be
presented in areas in the mapped visual field, where there are
defects, than in other areas in the mapped visual field.
[0294] Reference is now made to FIGS. 4A-4B which are schematic
diagrams illustrating some exemplary types of line series which may
be useful for mapping retinal lesions in accordance with some
exemplary embodiments of the present invention.
[0295] FIG. 4A schematically represents a mapping grid which may be
formed if all the linear test patterns used in the test were to be
simultaneously presented on the screen 112. The grid 500 thus
formed may include parallel vertical lines, such as for example the
vertical lines 502A, 502B, 502C, 502D, and 502E and parallel
horizontal lines, such as for example the vertical lines 504A,
504B, 504C, 504D, and 504E. It is noted that the horizontal lines
need not be equally spaced from each other. For example while the
line pairs 502A and 502B, 502B and 502C, and 502C and 502D may be
separated from each other by a cone angle D1, the line pairs 502D
and 502E may separated from each other by a cone angle D2.
Preferably D1 is larger than D2, such that the density of grid
lines at the central region of the grid 500 is higher than the
density of the lines at more peripheral regions of the grid 500.
This may enable mapping of the central foveal region at a higher
mapping resolution than the mapping of more peripheral foveal
regions.
[0296] It is noted however, that the horizontal and vertical lines
of the grid 500 may also be equally spaced from each other or may
be arranged differently than the arrangement of the lines
illustrated in FIG. 4A. Furthermore, it is noted that while the
lines of the grid 500 may be contiguous lines as shown in FIG. 4A
(for the sake of clarity of illustration), the lines of the grid
500 may also be segmented lines (not shown) or dotted lines (not
shown) or the like. Orthogonal or non-orthogonal slanted lines may
also be used (not shown) to map the retinal visual field.
[0297] The grid used for mapping may also include only the
horizontal lines shown in grid 500 or only the vertical lines of
grid 500. Furthermore, It is noted that the number and the density
of the lines shown in FIG. 4A is only shown by way of example and
the number of the lines as well as the separation between the lines
may be modified or changed depending, inter alia, on the required
retinal mapping resolution.
[0298] FIG. 4B schematically represents a mapping grid 510 which
may be formed if all the linear test patterns used in the test were
to be simultaneously presented on the screen 112. The grid 510 thus
formed may include a plurality of lines 512-517 which intersect at
a point. While the lines 512-517 are illustrated as having
identical lengths, their lengths may also vary. The angles
.alpha.1, .alpha.2, .alpha.3, .alpha.4, .alpha.5, and .alpha.6 may
be identical to each other and may be all equal to 60.degree.. It
is noted, however, that the number of lines in the grid and the
angle at which each line is inclined relative to the horizontal
line 515 may vary and may be different than the values illustrated
in FIG. 4B. Additionally, the number of the lines may vary such
that the grid may include more or less than the six lines 512-517.
While the lines 512-517 are illustrated as contiguous (for the sake
of clarity of illustration), the lines may also be segmented or
dotted lines, or the like.
[0299] It is furthermore noted that many variations and
permutations of the test patterns of the invention are possible and
are all considered to be within the scope and spirit of the present
invention. Similarly, the number of the test patterns forming the
mapping grid may vary as may their separation from each other,
their angular inclination within the mapping grid.
[0300] It will be apparent to those skilled in the art that the
exemplary mapping grids 500 and 510 do not represent the form or
shape of a single test pattern, but are rather virtual
representations of the images that would result if all the test
patterns of exemplary possible tests were to be projected
simultaneously on a surface.
[0301] In accordance with another embodiment of the invention, it
is also possible to present to the subject test patterns which
include a distortion or other modification of the predefined
reference pattern. For example, while the line 332 of screen 330 of
FIG. 3 comprises segments which are all arranged or aligned in a
straight line, a line 362 actually having a displaced segment 364
may also be presented to the subject on the screen 112 as
illustrated in screen 360 of FIG. 3.
[0302] The displaced segment 364 may be transiently presented at
it's displaced position, for example, for a duration of up to about
300 milliseconds, after which the displaced segment 364 may be
realigned with the other segments of the line 362, but other
different suitable presentation duration time values may also be
used.
[0303] It is noted that while in accordance with one embodiment of
the present invention, the displaced segment 364 may remain
displaced for the entire duration of presentation of the line 362,
preferably, the segment 364 is only transiently displaced as shown
and is then realigned with the remaining segments of the line 362
for the remaining part of the presentation of the line 362. This
method of presentation may better mimic the characteristics of the
image perceived by patients which have a retinal or choroidal
lesion when a segmented line similar to the segmented line 322 is
projected on a region having a retinal or choroidal choroidal
lesion as disclosed in detail hereinabove.
[0304] Generally, test patterns, such as for example the line 362
of screen 360 (FIG. 3) may be regarded as test patterns which
include an intentionally introduced distortion which may be similar
to distortions which may be seen or perceived by a patient having a
retinal or choroidal lesion when a non-distorted test pattern (such
as, but not limited to the line 332 of screen 330) is presented to
the patient. Such test patterns including a distortion may also be
referred to hereinafter as "artificially distorted" test patterns.
The presentation of such artificially distorted test patterns may
be used, inter alia, to ascertain that the subject is aware of the
visual distortion associated with a retinal or choroidal lesion,
and that his responses reliably reflect the perceived appearance of
lines presented to him.
[0305] It is noted that while in the exemplary artificially
distorted line 362 illustrated in screen 360 of FIG. 3 only one
segment 364 is shifted or displaced relative to the other segments
of the line 362, various other different types of distortions may
be used. In accordance with other exemplary embodiments of the
invention such distortions may include, but are not limited to,
displacing or misaligning more than one segment relative to the
rest of the segments (not shown) of the line 362, transiently or
briefly displacing or misaligning one or more segments relative to
the rest of the segments within part of the duration of
presentation of the line 362, tilting or changing the orientation
of one or more segments relative to the orientation of the
remaining segments (not shown), bending or otherwise changing the
shape of one or more segments, removing one or more of the segments
(not shown), blurring one or more of the segments (not shown),
changing the hue or color or brightness of one or more segments of
the test pattern (not shown), or introducing other types of
alterations to the test pattern which may resemble distortions or
alterations which may be perceived by a person having a retinal
lesion when such a person is presented with a non-distorted test
pattern or reference pattern, such and other changes or distortions
or modifications of the test pattern may, preferably, be transient
changes but similar non-transient changes may also be used.
[0306] It is noted that if the test patterns used in the test are
non-segmented, such as for example if the test pattern comprises a
contiguous (non-segmented) straight line (not shown), the
artificially distorted test patterns may include, but are not
limited to, bending one or more portions of the contiguous line
such that these portions are not straight (for example, such
distorted portions of the test pattern may be curved or wavy),
blurring or smearing one or more portions of the test pattern (not
shown), hiding (not presenting) one or more portions or parts of
the test pattern (not shown) or changing the hue or color or
brightness of one or more portions of the test pattern, or the
like. Other suitable visually perceivable types of distortions or
alterations of test patterns may also be used.
[0307] The presentation of such artificially distorted or otherwise
intentionally altered or modified test patterns to the patient or
test subject may also be advantageously used to detect cases in
which the patient is not paying attention to the test patterns due
to fatigue or due to any other reason. This may enable the
assessment of the degree of reliability of the test result. For
example, if the patient does not reliably and/or accurately report
the presence of the distortion or alteration in such artificially
distorted or otherwise altered test patterns presented to him
during the testing, this may be taken as an indication of a problem
and may indicate a possible need to repeat the test or
alternatively to label the test results as unreliable.
Additionally, the degree of correlation between the location of the
distortion or alteration on the presented test pattern and the
location of the distortion or alteration perceived and marked (or
reported) by the patient may be used to assess the accuracy of
perceiving and/or of the reporting of the location of the
distortion or alteration by the patient or tested subject.
[0308] It is noted that in the exemplary screen 320 of FIG. 3, the
segmented line 322 may be regarded as a pre-determined "reference
pattern" of the test. The patient may be asked and/or trained to
relate to the perceived image of the presented straight segmented
line 322 as the reference pattern against which to compare the
perceived images of the later presented test patterns. When the
test is first presented to a patient, the patient may be told by
the trainer or the individual administering the test that he is
about to be shown a straight segmented line (or any other reference
test pattern which is being used for the test). In this way, the
patient becomes aware of the reference pattern against which he is
expected to compare the perceived images of the test patterns which
are going to be presented to him as the testing proceeds. It is
noted that the patient may also be told before the testing begins
that he is to be presented with straight segmented lines (without
initially presenting to him such a line) and asked to compare the
perceived image of each of the lines presented to him with a
reference pattern which is a straight segmented line.
[0309] It is noted that the testing method of the present invention
is not limited to the "moving pattern" testing method disclosed
hereinabove, and may be modified in different ways, which are
considered to be within the scope of the present invention.
[0310] "Flash Test" Method
[0311] In this embodiment of the invention, a fixation target is
presented to the tested individual on a display device, such as but
not limited to the screen 112 of the display device 115 (FIG. 1).
After the tested patient has fixated on the fixation target, a test
pattern is briefly presented (flashed) at a first location on the
display device for a time duration which is sufficient to allow the
patient to perceive an image of the presented test pattern. The
image perceived by the patient in also referred to as a "perceived
image" of the test pattern. The patient may then be requested to
indicate whether he or she detected a difference between the
perceived image of the presented test pattern and a reference
pattern.
[0312] The tested patient may be informed by the trainer, or
ophtalmologist or the person delivering the test, before the test
is performed, that he is going to be presented with patterns
similar to or different than a reference pattern. The patient may
or may not be actually presented with the reference pattern before
the test begins. For example, if the reference pattern is a
straight segmented line, the patient may be verbally told that he
is going to be presented with a variety of test patterns that may
be similar to or may be different from a straight segmented line,
without showing the patient a straight segmented line (which is the
reference pattern in this non-limiting exemplary test) prior to the
presentation of the actual test patterns to the patient. In such a
case, the reference pattern is based on the prior acquaintance of
the patient with the reference pattern which is used. In other
words, previous knowledge of the patient of how a straight
segmented line looks is relied upon.
[0313] It is also possible (though not obligatory), however, to
present the reference pattern to the patient before the actual test
patterns are presented, in order to give the patient an idea of how
the reference pattern is supposed to look. While this may help the
patient to understand and familiarize himself or herself with the
form of the reference pattern, it is not a necessary part of the
test, since most patients may adequately perform the test just by
being told verbally what the reference pattern is, without being
presented with the actual reference pattern prior to the
presentation of the test patterns.
[0314] After the patient is presented with a test pattern, if a
difference was detected by the patient between the pattern
perceived by the patient as a result of the presentation of the
test pattern and the reference pattern, the patient may indicate
the region or regions or segments or components of the perceived
pattern at which a difference or differences were noticed. The
presence and the location of the difference(s) which are detected
and indicated by the patient may be stored for further processing
and analysis as disclosed hereinabove. This procedure may be
repeated several times while changing the location of the test
pattern relative to the fixation target on the screen 112. The
number of repetitions and the location of the presented test
patterns are such that a suitable area of the visual field of the
tested eye of the patient is mapped for detection of possible
retinal lesions or pathologies.
[0315] Reference is now made to FIGS. 5A-5J which are schematic
diagrams illustrating the patterns displayed on the screen 112 of
the subject's display device 115 at various different exemplary
steps of another embodiment of an eye test performed by the system
illustrated in FIG. 1, and the possible appearance of the test
patterns as they may be perceived by the test subject at some
exemplary steps of the eye test.
[0316] In performing the flash test, the patient or test subject
may be positioned before the screen 112, with the distance of the
tested eye being preferably approximately 50 centimeters from the
screen 112. Other different distances may however also be used
depending, inter alia, on the dimensions of the screen 112, and on
the size of the displayed test patterns.
[0317] The "flash test" method may begin by presenting to the
patient or test subject one or more log-on screens, such as, but
not limited to, the screen 300 schematically illustrated in FIG. 3.
Other additional screens (not shown) may also be presented for
entering other patient demographic data or the like. Once the
patient identity has been established, screen 370 (FIG. 5A) may be
presented to the patient.
[0318] A fixation target 372 is displayed on the screen 112. The
fixation target 372 may be a circular pattern or may be any other
suitably shaped pattern as disclosed in detail hereinabove for the
fixation target 228 of FIG. 3. A cursor 373 may also be displayed
on the screen 370. If the patient is trained to take the test, the
trainer or test supervisor may explain to the patient that he or
she should cover one eye (by hand or by using a suitable eye
occluding device or patch), look at the screen 370 with the
non-covered eye, and bring the cursor 373 to point at the fixation
target 372.
[0319] Preferably, but not obligatorily, the movement of the cursor
373 may be restricted to the horizontal direction. For example, in
accordance with one possible implementation of the method, the tip
of the arrowhead-like pointing part 373A of the cursor 373 may be
pointed upwards and it's movement may be restricted along an
imaginary non-visible horizontal line (not shown) intersecting the
fixation target 372. The patient may bring the cursor 373 to point
at the fixation target 372 by using a mouse or any other suitable
pointing device, as disclosed in detail hereinabove for the moving
line method.
[0320] Similar to the fixation target 228 of FIG. 3, the fixation
target 372 may be sized so that it is large enough to be seen by
the patient or test subject but small enough so that bringing the
cursor 373 to the fixation target 372 is a demanding task for the
test subject. This causes the subject to fixate his vision on the
fixation target 372. Upon bringing the cursor 373 to the fixation
target 372, the subject may provide a suitable indication that he
has positioned the cursor 373 to point at the fixation target 372.
For example, the patient or test subject may provide the indication
by clicking on a button of the mouse 125 or by depressing a
predetermined key on the keyboard 120 (or by suitably using any
other suitable pointing device known in the art or disclosed
hereinabove). This patient input may serve as an indication or
verification that visual fixation on the fixation target 372 has
been achieved.
[0321] After the patient indicates fixation as disclosed
hereinabove, a test pattern in the form of a segmented straight
line 382 is presented to the patient (see screen 380 of FIG. 5B).
It is noted that while the exemplary test pattern illustrated in
FIG. 5B is a segmented straight line 382 as disclosed hereinabove
for the moving line test method, other types of different test
patterns (not shown) may however also be used. The segmented
straight line 382 may be presented on the screen 112 immediately
after the patient clicks the mouse 125 or may be presented after a
delay. If a delay is used, the duration of the delay may preferably
be in the range of approximately 0-200 milliseconds, but other
higher values of the duration of the delay may also be used. The
segmented straight line 382 may be displayed on the screen 112 for
a short duration. Preferably, the duration of presentation of the
test pattern (the line 382) on the screen 112 may be in the range
of approximately 100-160 milliseconds. It was practically found
that most patients perform the test well with the test pattern
presentation duration in this range which enables to keep the
duration of a test in the approximate range of 2-3 minutes (for a
typical test including the presentation of 23 vertical segmented
lines and 23 horizontal segmented lines).
[0322] It is noted that duration of presentation may also be
shorter or longer. Typically, a duration of approximately 10-20
milliseconds may be on the threshold of observation for most
patients. Thus, presentation duration values which are longer than
10-20 milliseconds may have to be used for most patients. The
threshold of observation may, however, vary, inter alia, with the
patient's age, visual acuity, or the like.
[0323] It is also noted that the test pattern presentation duration
may also be longer than 160 milliseconds, but this may increase the
overall test duration.
[0324] One advantage of the relatively short duration of the
presentation of the test pattern (also referred to herein as
"flashing" of the test pattern) may be that the eye/brain system of
the patient may not have enough time to "fill-in" the distorted or
missing or different parts of the perceived image of the test
pattern, as it may do when the test pattern is static or is
presented for a relatively long period of time. This may
advantageously reduce or prevent such "filling-in" phenomena
disclosed in detail hereinabove, which may decrease the probability
of the patient not observing or not detecting (and therefore not
reporting) a difference in the appearance of the perceived test
pattern (as may often occur in the use of the Amsler test).
[0325] It may be further explained to the patient (either before
performing the test or while the test is being taken) that he is
going to be presented with test patterns on the screen 112. The
patient may, for example, be told that the presented test patterns
are going to be segmented straight lines, and that the reference
pattern against which he is to compare what he actually perceives
on the screen 112 is a segmented straight line.
[0326] The patient may further be instructed that if he or she
detects any difference between the perceived form of the presented
test pattern or of one or more parts or portions thereof and the
reference pattern (which is a straight segmented line in the
non-limiting example illustrated in FIGS. 5A-5J), he or she is
requested to indicate the approximate location of the part or parts
which were perceived to differ from the reference pattern, as is
disclosed in detail hereinafter.
[0327] For example, it may be explained to the patient that one or
more of the segments of the straight line may deviate from
linearity or may appear to move, or may appear wavy, or may appear
to bulge or to deviate or to be distorted such that they are not
perceived to be arranged as a straight line, and that other
differences may also be observed such as, for example, a movement
of one or more segments or parts of the perceived image of the test
pattern relative to other parts or segments or portions of the
perceived test pattern, or a dimming or brightening of some
segments relative to the rest of the segments, or a change in the
hue or color of some segments relative to the hue or color of other
segments, or a fuzziness or blurring of one or more segments
relative to the other segments, or that one or more segments or
portions of the segmented straight line may appear to be missing,
and that other differences may also be perceived.
[0328] FIG. 5C schematically illustrates a screen 390 which is a
representation of how the presented screen 380 (FIG. 5B) may be
perceived by a patient having a retinal lesion while the patient's
tested eye is fixated on the fixation target 372. The perceived
image perceived by the patient may be a distorted segmented line
392 (FIG. 5C). In the perceived distorted line 392, the segments
392A, 392B, and 392C are perceived as shifted or distorted, or
moving, or forming a bulge such that they are not arranged in a
straight line. This may be due to the presence of a retinal
lesion.
[0329] After the presentation of the test pattern is terminated,
the test pattern 382 disappears from the screen 112 by terminating
the displaying thereof on the screen 112. The patient may then
indicate or mark the approximate location of the perceived region
of difference or distortion on the perceived image. This marking or
indicating may be performed, for example by the patient using the
mouse 125 to move the cursor 373 to the region of the screen 112
where the difference was observed or detected. FIG. 5D illustrates
the appearance of a screen 400 after the patient moved the cursor
373 to the approximate position on the screen at which the patient
observed the distortion in the perceived image illustrated in FIG.
5C. This position roughly matches the region where the segments
392A, 392B, and 392C (of FIG. 5C) were perceived by the patient as
shifted or distorted. After the positioning of the cursor 373 at
the approximate position at which the difference or distortion was
observed the patient may click a button on the mouse 125. The
computer system 105 may thus determine from the position of the
cursor 373 in screen 400 (FIG. 5D) the location on the test pattern
at which a difference or distortion was observed or detected by the
patient in the perceived image 392 of the test pattern 382 which
was presented in screen 380 (of FIG. 5B). This location may be
stored as data in the computer system 105.
[0330] It is noted that while in screens 370 and 380 (of FIGS. 5A
and 5B, respectively) the movement of the tip 373A of the
arrowhead-like cursor 373 was restricted along an imaginary,
non-visible, horizontal line (not shown) intersecting the fixation
target 372, after the termination of the presentation of the test
pattern 382, the cursor is preferably not restricted and may be
moved to any point on the screen 400. Alternatively, the moving of
the cursor 373 may remain vertically restricted as disclosed
hereinabove, in which case the patient may mark the location of the
observed distortion or difference by moving the cursor 373
horizontally (not shown) until it reaches a location which is above
or below the region at which the difference or distortion was
observed on the perceived test pattern, (depending on whether the
location of the appearance of the test pattern was below or above
the fixation target 372, respectively).
[0331] The computer system 105 may thus store data representative
of the location (or locations) marked by the patient. In accordance
with one exemplary embodiment of the invention, the data may
include the position of the test pattern 382 on the screen 380 and
the position on the test pattern 382 which is equivalent to the
horizontal position marked by the cursor 373 on the screen 400
(which is indicative of the location which was marked by the
patient as the approximate region of the distortion perceived by
the patient). Other different methods of storing the data may also
be used as may be apparent to those skilled in the art.
[0332] It is noted that the computer 105 may also store other
information or data associated with the presented test pattern. For
example, the stored data may include, but is not limited to, the
number of the test pattern (which may be indicative of the order of
presentation of the particular test pattern within the test), the
orientation of the test pattern (for example, vertical or
horizontal, or the like), or any other data related to other
parameters of the test pattern.
[0333] After the marked position of the distortion is stored, the
patient may initiate the presentation of a new test pattern by
repositioning the cursor 373 to point at the fixation target 372
and clicking a button on the mouse 125 as disclosed for screen 380
(of FIG. 5B) to indicate the achieving of fixation. This may cause
the presentation of a new test pattern 402 as illustrated in the
screen 410 of FIG. 5E. In this exemplary screen, the test pattern
402 is briefly presented at a new location on screen 410, different
than the location of the test pattern 382 on screen 380 (FIG. 5B).
The patient may perceive the presented test pattern 402 as a
segmented straight line with no distortion (or no difference from
the reference pattern) if there is no retinal lesion in the retinal
region on which the image of the test pattern 402 is projected when
the patient maintains visual fixates on the fixation target 372.
The patient does not mark any position on the screen 410 since no
distortion or difference from the reference pattern were observed
by the patient. The patient may then proceed by visually fixating
on the fixation target 372 and clicking on the mouse 125 to
initiate the presenting of a new test pattern (not shown).
[0334] It is noted that in accordance with one embodiment of the
invention, the cursor 373 may be automatically shifted to a new
position away from the fixation target 372 following the
termination of the presentation of the test pattern. This may be
advantageous since it may force the patient to bring the cursor 373
again to point at the fixation target 372 which may ensure proper
visual fixation before the presentation of each new test pattern.
This however is not mandatory, because it may be possible to train
the patient to perform visual fixation on the fixation target 372
prior to clicking the mouse to initiate the presentation of an
additional test pattern, and because it may also be possible to
independently monitor patient fixation by the presentation of
artificially distorted test pattern as disclosed hereinabove and
hereinafter.
[0335] In accordance with one embodiment of the invention, after a
sufficient number of test patterns at appropriate locations have
been presented to the patient to adequately map the desired field
of vision with a desired resolution, the test may be terminated. In
accordance with another embodiment of the invention, the test may
further continue by changing the orientation of the presented test
patterns such that a new sequence of test patterns is presented to
the patient which test patterns are vertically oriented segmented
straight line.
[0336] In screen 420 of FIG. 5F a vertically oriented test pattern
422 is illustrated. Preferably, but not necessarily, the shape,
length and number of segments of the vertically oriented test
pattern 422 may be similar to the shape, length and number of
segments of the horizontally oriented test patterns previously
presented to the patient (such as, for example, the horizontally
oriented test pattern 382 of FIG. 5B). This, however is not
mandatory, and the shape, or the length or the number of segments
of the vertically oriented test patterns may be different than
those of the horizontally oriented test patterns.
[0337] If the patient noticed no difference or distortion in the
perceived pattern (not shown) of the test pattern 422 presented to
the patient, the patient may re-fixate on the fixation target 372,
and indicate visual fixation by clicking the mouse 125 to cause the
presentation of a new (vertically oriented) test pattern.
[0338] FIG. 5G illustrates an exemplary (vertically oriented) test
pattern presented to the patient during a part of the test. The
test pattern 432 is presented in a location of screen 430 as
illustrated in FIG. 5G.
[0339] FIG. 5H schematically illustrates a screen 440 which is a
representation of how the presented screen 430 (of FIG. 5G) may be
perceived by the patient having a retinal lesion while the
patient's tested eye is fixated on the fixation target 372. The
perceived image perceived by the patient may be a distorted
segmented line 442 (FIG. 5H). In the perceived distorted line 442,
the segments 442A, 442B, and 442C are perceived as shifted or
distorted, or forming a bulge such that they are not arranged in a
straight line. This perceived distortion may possibly be due to the
presence of the same retinal lesion which caused the distortion in
the perceived image 392 (FIG. 5C) of the presented test pattern 382
of FIG. 5B. The distortion in the perceived image 442 may however
also be due to the presence of another different retinal
lesion.
[0340] After the termination of the presentation of the test
pattern 432 (FIG. 5G), the patient may mark the location of the
perceived distortion as illustrated in screen 450 of FIG. 5I by
moving the cursor 373 to point at the approximate location of the
distortion and clicking the mouse 125 which stores data
representing the location of the observed distortion in the
computer system 105, as disclosed hereinabove. Additional vertical
test patterns at different locations may then be presented to the
patient until the mapping of the retina using vertically oriented
test patterns is completed at a desired resolution. Testing of the
second eye of the patient may then be also performed by covering or
occluding the already tested eye of the patient and repeating the
same testing procedure for the uncovered non-tested eye.
[0341] The Use of "Artificial Distortions" in the Flash Test
Method
[0342] Preferably, in accordance with an embodiment of the
invention, it may be possible to include intentional distortions in
the test patterns presented in the flash test method disclosed
hereinabove by presenting the patient with artificially distorted
test patterns. The artificially distorted patterns may include,
inter alia, any of the types of distortions included in the
artificially distorted test patterns disclosed hereinabove for the
"moving line" test method (for one, non-limiting example of such an
artificial distortion see screen 360 of FIG. 3). Thus, some of the
test patterns presented to the patient may be artificially
distorted, as disclosed hereinabove. For example, one out of three
(approximately 30%) test patterns presented to the patient may be
an artificially distorted pattern. Other different ratios of
artificially distorted to non-distorted test patterns may also be
used, as well as tests in which all test patterns include
artificial distortions.
[0343] Among the advantages of presenting artificially distorted
test patterns is, that this may train the patient in what may be
the appearance of a perceived distortion if a retinal lesion is
present. This training may improve the patient's ability to detect
and report such distortions if such a distortion or similar
distortions appear in the perceived image following the
presentation of a non-distorted test pattern to the patient.
[0344] Another advantage, as explained hereinabove, may be the
possibility to assess the degree of attention of the patient, and
the reliability of the test results. Thus, if the patient fails to
reliably report the presence and the location of the distortions
displayed in the artificially distorted test patterns, this may be
used as an indication of possible lack of attention of the patient,
due to fatigue or other reasons, or this may also be used as an
indication that something is wrong with the test presentation or
with the test results, or with the patient's ability to visually
perceive the test patterns, in which case the test results may be
ignored (such as, for example, when the test is performed by the
patient alone without the supervision of a trainer or supervisor).
If a trainer or supervisor is present near the patient and such a
testing non-reliability is reported, for example by an appropriate
error message (not shown) appearing on the screen 112 or otherwise,
the supervisor or trainer may stop the test (and may cancel the
record of the test results if appropriate) and may try to find and
rectify the reasons for the patient's failing to reliably report
the presence and location of the distortions.
[0345] For example, the trainer or supervisor may check if the
patient's tested eye is positioned at the appropriate distance from
the screen 112, or if the patient is fatigued or not paying
attention to the test patterns or not properly fixating his vision
at the fixation target 373, or the like. Such problems may be thus
rectified and another test may be initiated if desired.
[0346] FIG. 5J illustrates one possible form of an artificially
distorted test pattern which may be possibly used in the example of
the flash testing method illustrated in FIGS. 5A-5I. In screen 460
of FIG. 5J an artificially distorted line 462 is illustrated as
presented to the patient on the screen 112. The segments 462A, 462B
and 462C of the presented line 462 are positioned and oriented such
that they are not aligned (or mis-aligned) with the remaining
segments of the test pattern 462. In other words, while the
remaining segments of the test pattern 462 are aligned to form a
straight line, the segments 462A, 462B and 462C form a bulge or
curved part or wavy part of the test pattern 462. The test pattern
462 (which may be presented on the screen 112 of the display device
115) is thus an artificially intentionally distorted test pattern.
Thus, when the artificially distorted test pattern 462 is presented
to the patient who is visually fixated on the fixation target 373,
the patient may perceive the distortion as a deviation of the
segments 462A, 462B and 462C from the expected reference pattern of
a straight segmented line.
[0347] The patient may then proceed to indicate or mark the
approximate location of the perceived distortion by bringing the
cursor 373 to the approximate location of the perceived distortion
and clicking the mouse 125 as disclosed in detail hereinabove. For
example, the patient may position the cursor 373 at the approximate
position on the screen 112 at which the patient perceived the image
of the segment 462B while the test pattern 462 was presented
(flashed) on the display device 115, and may click on the mouse 125
to input and store the approximate location of the perceived
distortion in the test pattern 462. The location reported by the
patient may be compared to the known location of the distortion in
the presented artificially distorted test pattern 462.
[0348] It is noted that when the patient marks the location of the
perceived distortion, an error or inaccuracy in localization may
occur along a single dimension only (the horizontal dimension for
horizontal test pattern, or the vertical dimension for vertical
test pattern), since the location of the presented test pattern is
known to the system.
[0349] It is also noted that if the patient detects or observes two
or more spatially distinct distortions or abnormalities along the
presented test pattern, the patient may mark the approximate
location of all such detected distortions or visual abnormalities
by suitably bringing the cursor 373 to the location at which the
additional distortion or visual abnormality was observed and
clicking the mouse 125. Thus, the data stored for a test pattern
may include the location on the test pattern of more than one
detected distortion or visual abnormality.
[0350] Typically (but not necessarily), about a third
(approximately 30%) of the test patterns presented to the patient
may be artificially distorted test patterns. The percentage of the
artificially distorted test pattern out of all the test patterns
presented to the patient may however vary, depending, inter alia,
on previous knowledge of the test performance of the same patient
in past tests, or on other considerations. Thus, in some tests, all
the test patterns may be artificially distorted.
[0351] It is noted that the tests of the present invention may be
performed such that only a certain percentage of the test pattern
include an AD, or, alternatively, the tests may be performed such
that all the test patterns in the test include an AD.
[0352] Additionally, the artificially distorted test patterns may
be randomly or pseudo-randomly distributed among the rest of the
test patterns during a test so that the patient cannot predict the
time of presentation of the artificially distorted test patterns by
learning the sequence of presentation of these signals.
[0353] It is noted that generally vertically oriented artificially
distorted test patterns (not shown) may also be presented to the
patient (the word "generally" refers to the vertical orientation of
the majority of the non-distorted segments which are aligned along
an imaginary straight line, even if some of the segments may be
horizontally displaced in the region of the artificial
distortion).
[0354] Typically, the location of the distorted portion or segments
on the artificially distorted test pattern may be randomly or
pseudo-randomly changed or altered in different presentations of
artificially distorted test patterns performed within a test. Such
random alteration of the location of the artificial distortion
along the test pattern is advantageous because it makes it more
difficult for a patient to cheat (either intentionally or
non-intentionally) in comparison with a situation in which the
distortion is always presented at a fixed location on the test
pattern.
[0355] If the patient fails to reliably identify and report the
presence and the location of the distortion presented in a
predetermined percentage of the artificially distorted test
patterns which were presented to the patient in a test, the test
results may be ignored or discarded as unreliable. For example, in
accordance with one non-limiting exemplary embodiment of the method
of the present invention, if the patient did not report reliably
the presence and the location of the artificial distortion (or
another test pattern modification used in the test) in 20% of the
total number of artificially distorted test patterns presented
within a test, the test results may be ignored or discarded as
unreliable.
[0356] Thus, in accordance with such an exemplary (non-limiting)
test reliability criterion, if in a test the patient was presented
with 60 test patterns, and 20 test patterns out of the 60 test
patterns were artificially distorted (or otherwise modified) test
patterns, the patient has to reliably report the presence and
location of the artificial distortion (or of any other test pattern
modification which was used in the modified test pattern) in at
least four out of the twenty presented artificially distorted test
patterns in order for the test results to satisfy the reliability
criterion.
[0357] It is noted that in accordance with the exemplary embodiment
of the reliability criterion disclosed hereinabove, it is not
enough for the patient to just identify the presence of the
distortion or modification which was artificially introduced in the
presented test pattern, but the patient has to correctly mark the
position of the artificial distortion (or other test pattern
modification) in the test pattern within a specified predefined
positioning accuracy criterion.
[0358] Typically, in accordance with one possible exemplary
embodiment of the present invention, the position marked by the
patient as the position of the distortion (or other modification,
if used) has to fall within a 1.5.degree. cone angle on each side
of the center point of the artificial distortion in to satisfy the
position accuracy criterion, but other different cone angles may
also be used.
[0359] Reference is now made to FIG. 6 which is a schematic diagram
useful in understanding an exemplary positioning accuracy criterion
which may be used in the eye testing method, in accordance with one
exemplary embodiment of the present invention.
[0360] The segmented line 532 schematically represents an
artificially distorted horizontal line 532 as presented (flashed)
on the screen 112 to the subject 100. The segment 529 represents
the approximated center of the artificial distortion of the line
532 as presented on the screen 112. The tips of the arrows 541,
542, 543, 544 and 545, schematically represent some possible
locations where a subject may potentially mark the position of the
approximate the center of the perceived distortion. It is noted
that the points clicked on by the subject (which are schematically
indicated by the points at the tip of the arrows 541, 542, 543, 544
and 545) need not be on the exact line 532 as perceived by the
patient and may be either on or below or above the position on the
screen 112 at which the line 532 was briefly presented. The dashed
line 519 schematically represents an imaginary vertical line
passing through the center of the segment 529 and the dashed lines
515 and 517 schematically represent two imaginary lines parallel to
the vertical line 519 and extending to the end (not shown) of the
screen 112. The distance S1 between each of the imaginary lines 515
and 517 and the imaginary line 519 is equivalent to a cone angle of
1.5.degree. of the visual field of the subject (when the subject's
eye is positioned 50 centimeters from the screen 112).
[0361] If the position marked by the subject 100 falls on one of
the imaginary lines 515 and 517 or falls anywhere between the two
lines 515 and 517, the marked position passes (satisfies) the
positioning accuracy criterion and the marked position is deemed to
be accurate. If the position marked by the subject 100 falls on the
region on the left side of the imaginary line 515 or on the screen
region on the right of the imaginary line 517, the marked position
does not satisfy the positioning accuracy criterion and the marked
position is deemed to be inaccurate. Thus, for example, the marked
positions represented by the tip of the arrows 541 and 545 do not
satisfy the positioning accuracy criterion while the marked
positions represented by the tip of the arrows 542, 543 and 544
satisfy the positioning accuracy criterion.
[0362] It is noted that other different types of positioning
accuracy criteria may also be used. For example the cone angle
represented by the distance S1 may have other values which are
smaller or larger than 1.5.degree.. Furthermore, if the test
patterns used are slanted lines, other positioning accuracy
criteria may need to be established and used.
[0363] It is further noted that the satisfying of the positioning
accuracy criterion may be computed or evaluated by the computer 105
or by any other suitable computing device, using any suitable
computational algorithm as is known in the art.
[0364] Analysis of Test Results
[0365] The results of the tests performed as disclosed hereinabove
may need to be suitably analyzed in order to provide the patient
with proper instructions, and possibly his health care provider
with a report of the test results. In the case where the patient
has been trained to perform the test at home using a desk-top
computer or a portable computer (a laptop computer) or the like, if
a possible retinal lesion is detected in the test, the patient may
be preferably provided with an output which may instruct the
patient to promptly visit his ophtalmologist or an eye clinic for a
thorough eye examination in order to check the existence of the
suspected lesion. If upon this eye examination a lesion is
verified, proper therapeutic treatment may be timely administered
to the patient, which may substantially improve patient's prognosis
due to early detection of the lesion. If no lesion is detected or
suspected, the patient may be informed after the test is finished
that the results are negative (no lesion is suspected).
[0366] Theoretically, if a single occurrence of a perceived
distortion of a test pattern is reported or marked by the subject
after a non-distorted test pattern is presented to the patient, the
patient may be diagnosed as positive and the system may recommend
or instruct the patient to visit an ophtalmologist for further eye
examination. Such a simple diagnostic criterion may, however,
result in a relatively large percentage of false positive
diagnoses. This is because many patients may report a distortion in
a certain percentage of the presented non-distorted test patterns.
Thus, such a simple diagnostic criterion may not be widely
applicable to all patients and may possibly be used only for a
certain sub-population of patients (such as for example in very
high risk patients in which it may be decided that a high
percentage of false positive diagnoses is tolerable). It is,
however noted, that it is possible to use such a single reporting
of a perceived distortion for diagnosing attested individual as
positive provided the empirically determined percentage of false
positive results is acceptable in view of the application used.
[0367] In accordance with another embodiment of the invention, in
test embodiments in which there are multiple presentations of the
test pattern the test may result in a positive result if the tested
individual indicates a perceived distortion in a non-distorted
position of a presented test pattern a preselected number of times.
For example, the diagnostic algorithm may output a positive result
if the tested individual indicates a perceived distortion in a
non-distorted position of a presented test pattern three or more
times within the same test. The number three in this non-limiting
example, is the threshold for outputting a positive test
result.
[0368] This may have the advantage of reducing the number or the
percentage of false positive results in the test. In accordance
with such an embodiment of the test of the present invention, the
threshold for outputting a positive test result may thus vary
between a single occurrence of a perceived distortion and any
desired number higher than one of such perceived distortions. The
choice of the threshold number may depend, inter alia, on the
number of presentations of the test pattern within a single test,
the number of repetitions of presenting a test pattern at the same
retinal location, the acceptable percentage of false positive
results, and other practical considerations.
[0369] In accordance with one possible embodiment of the test, a
positive result may be output if the number of presentations of a
non-distorted test pattern in which the patient indicated the
presence of a perceived distortion is equal to or exceeds the
threshold number irrespective of the location of projecting of test
patterns on the retina.
[0370] In accordance with another possible embodiment of the test,
a positive result may be output if the number of presentations of a
non-distorted test pattern in which the patient indicated the
presence of a perceived distortion is equal to or exceeds the
threshold number and all the test patterns for which a distortion
was indicated were projection the same retinal location.
[0371] For most patients, however, other diagnostic criteria may
have to be used for reducing the probability of false positive
diagnosis.
[0372] In accordance with one possible embodiment of the invention,
in order to establish if one or more visual disturbance was
reliably detected, the data collected and stored in the test is
processed as follows.
[0373] The data stored for all the non distorted test patterns are
checked to see if any segment or component or portion was marked by
the patient on any of the test patterns presented in the test. If
such a marked segment or component or portion is found, the data
for other test patterns is checked for the presence and location of
marked segments in other different test patterns. While the finding
of a single marked location in a single test pattern may be
regarded as an indication of a suspected retinal lesion or retinal
abnormality, such a single marked location may have been
erroneously marked. It is therefore preferred to corroborate such a
result by checking the data obtained for other different test
patterns to find out if another location was marked on another test
pattern. If two locations were indeed marked by the subject in two
different test patterns it may be checked or computed if these two
locations satisfy a proximity criterion.
[0374] Reference is now made to FIGS. 7A and 7B which are schematic
diagrams useful in understanding exemplary diagnostic criteria
which may be used in some embodiments of the present invention.
[0375] It is noted that the locations of the distortions marked and
stored in the computer 105 as disclosed hereinabove may be
normalized since they are all known relative to the fixation
target. In other words, a correction may be computed to compensate
for the movement of the fixation target on the screen 112.
Therefore, the coordinates of the marked locations may be
normalized relative to the fixation target (if the fixation target
moves on the screen 112 as is the case in the moving line test). In
this way all the marked points may be related to each other for
performing the computations of the diagnostic criteria. In the
disclosed exemplary embodiment of flash test, there is no need for
normalization since the fixation point does not change its position
on the screen 112, and therefore the locations (coordinates) of the
marked locations of the distortions or modifications may be used
directly without normalization. It is however noted, that if an
embodiment of the flash test is used in which the position of the
fixation target changes during the test, the coordinates of the
positions marked by the tested individual may be similarly
normalized.
[0376] Different proximity criteria may be used for different
combinations of test patterns. The computation is performed on
pairs of marked locations in two test patterns. If the pair of
marked locations came from test patterns which are orthogonal to
each other (such as for example a horizontal straight segmented
line and a vertical straight segmented line), the proximity
criterion is satisfied if the distance between the two marked
locations is equal to or smaller than a cone angle of 3.degree.
(three degrees) assuming that the subject's eye was at a distance
of 50 centimeters from the screen 112 during the test.
[0377] The point 570 of FIG. 7A schematically represents the
position of a first location marked by the subject in response to
the presentation of a first test pattern. The circle 572 has a
radius R which is equivalent to a cone angle of 3.degree. (three
degrees) assuming that the subject's eye was at a distance of 50
centimeters from the screen 112 during the test. If a another point
which represents the location marked by the subject on another test
pattern orthogonal to the first test pattern falls on or within the
circumference of the circle 572, the proximity criterion (for pairs
of orthogonal test patterns) is met, indicating the presence of a
retinal lesion. If the other point falls outside of the
circumference of the circle 572, the proximity criterion is not
met. For example, each point of the points 576 and 578 meets the
proximity criterion with respect to the point 570, while the point
574 does not meet the proximity criterion with respect to the point
570.
[0378] It is noted that if the distance between the tested eye and
the screen 112 is different than 50 centimeter, the proximity
criterion may need to be changed by changing the value of the
radius R.
[0379] If the two points being checked come from locations marked
on test patterns that are parallel (for example, two differently
located straight segmented lines which are parallel), another
proximity criterion is used.
[0380] The point 580 of FIG. 7B schematically represents the
position of a first location marked by the subject in response to
the presentation of a first test pattern. A rectangle 590
surrounding the point 580 has a horizontal side HS which is
equivalent to a cone angle of 4.degree. (four degrees) and a
vertical side VS which is equivalent to a cone angle of 6.degree.
(six degrees) assuming that the subject's eye was at a distance of
50 centimeters from the screen 112 during the test. The point 580
is disposed at the geometrical center of the rectangle 590. If
another point which represents the location marked by the subject
on another test pattern parallel to the first test pattern falls on
or within the circumference of the rectangle 590, the proximity
criterion (for parallel test patterns) is met indicating the
presence of a retinal lesion. If the other point falls outside of
the circumference of the rectangle 590, the proximity criterion is
not met. For example, each point of the points 582, 584, and 576
meets the proximity criterion with respect to the point 580, while
the point 588 does not meet the proximity criterion with respect to
the point 580.
[0381] It is noted that the proximity criteria disclosed
hereinabove were empirically determined and that many other
different types of criteria may be used, depending, inter alia, on
the purpose of the test, the needed accuracy, the desired level of
false positive diagnosis, and the particular group of patients for
which the test needs to be applied. Thus, the proximity criteria
indicated above are given by way of example only and other
proximity criteria may be applied which are all within the scope of
the invention.
[0382] It is further noted that when the test includes test
patterns with artificial distortions, any locations which are
marked by the subject which are within approximately 2.83.degree.
(2.83 degrees) on each side of the center of the artificial
distortion are removed from the data prior to performing the
calculations for checking any of the proximity criteria to prevent
spurious positive results.
[0383] It is, however, noted that if the size and/or shape of the
artificial distortion is changed, a different distance from the
center of the distortion may be used for ignoring data which is
assumed to result from the presence of the artificial distortion.
It is also noted that when ignoring such data as described
hereinabove, the same distance may be applied for all the
artificial distortions presented provided that the longitudinal
dimension of all the artificial distortions along the test pattern
is identical. The application of this distance criterion may,
however, be modified if the longitudinal dimension of the
artificial distortions presented varies for different artificial
distortions presented within the same test, as is disclosed in
detail hereinafter.
[0384] FIG. 8 is a schematic flow diagram useful in understanding a
method for performing a test session and analyzing the results of
the test session, in accordance with one possible embodiment of the
present invention.
[0385] A test session may include one or more tests and begins by
the patient performing a first test (step 550). The tests may be a
moving line test or a flash test but in one session all tests are
of the same type. After the first test is completed, the data is
analyzed (step 552). The analysis may be performed using the
proximity criteria as disclosed hereinabove and may result in any
of three types of analysis results as follows:
[0386] 1) a positive result is generated if a retinal lesion is
found from the results of the first test by having at least two
marked locations in two separate test patterns which meet the
proximity criteria disclosed hereinabove.
[0387] 2) a negative result is generated if the patient did not
mark any location in any of the test patterns presented in the
test.
[0388] 3) a verify result is generated if the patient selected and
marked locations on one or more test patterns presented during the
test, but the marked locations did not meet the proximity
criteria.
[0389] If the results of the analysis of step 552 generate a
positive result, the session ends with a positive result (step 564)
indicating that a lesion has been detected, and the session is
terminated.
[0390] If the results of the analysis of step 552 generate a
negative or a verify result, a second test is run (step 554). The
second test is a repetition of the first test. The results of the
second test are analyzed (step 556) according to the same method as
in the analysis of step 552 except that the analysis is run on the
pooled results of the first and the second test.
[0391] If the results of the analysis of step 556 generate a
positive result, the session ends with a positive result (step 564)
indicating that a lesion has been detected, and the session is
terminated.
[0392] If the results of the analysis of step 556 generate a
negative result, the session ends in a negative result and is
terminated (step 562). If the results of the analysis of step 556
generate a verify result a verification test is run (step 558). The
verification test may be different than the first test and the
second test in that it does not present to the patient the full
complement of the test patterns which are normally included in the
first and the second test, but presents to the patient only test
patterns which were previously marked by the patient in the pooled
results of the first and the second tests. Additionally, while the
first and second tests may include artificially distorted test
patterns, preferably, the verification test does not include
artificially distorted test patterns.
[0393] After the verification test is performed, an analysis is
performed on the pooled results of the first test, the second test
and the verification test (step 560).
[0394] If the results of the analysis of step 560 generate a
positive result, the session ends with a positive result (step 564)
indicating that a lesion has been detected, and the session is
terminated.
[0395] If the results of the analysis of step 560 generate a
negative or a verify result, the session ends with a negative
result (step 562) and the session terminates.
[0396] Experimental Results
[0397] Reference is now made to FIG. 9 which is a bar graph
representing experimental results comparing the performance of the
standard Amsler grid test with the performance of the eye test of
the present invention.
[0398] The bar graph of FIG. 9 represents the results of testing
performed on 108eyes of patients with clinically diagnosed forms of
AMD and on a group of control patients which had a normal retina
(the control group).
[0399] The test was performed using the flash method as disclosed
hereinabove.
[0400] The test patterns used were 23 vertical segmented straight
lines and 23 horizontal straight segmented lines, each line
spanning a 14.degree. cone angle at a distance of 50 centimeters of
the eye from the screen 112. The segments were rectangular white
segments on a black background, each segment spanning
0.22.degree..times.0.22.degree. cone angle. The segments of each
line were separated from each other by a cone angle of
0.6.degree..
[0401] The results of the control group which included 51 patients
clinically diagnosed as having normal retinas, are represented in
the bar pair labeled I (normal retina).
[0402] A group with 108 patient included four subgroups. The first
subgroup (labeled II) included 18 patients clinically diagnosed as
having early AMD without high-risk characteristics (HRC) as in
known in the art.
[0403] The second subgroup (labeled III) included 35 patients
clinically diagnosed as having early AMD with high-risk
characteristics (HRC) as in known in the art.
[0404] The third subgroup (labeled IV) included 23 patients
clinically diagnosed as having late AMD with geographic atrophy
(GA) as in known in the art.
[0405] The fourth subgroup (labeled V) included 32 patients
clinically diagnosed as having choroidal neovascularization (CNV)
as in known in the art.
[0406] The results of the MCPT for the subgroups are represented by
the hatched bar of each bar pair and the results of the standard
Amsler grid test are represented by the unfilled bar of each bar
pair. The height of the bars represents the percent of the patients
in each relevant group which was diagnosed as positive in the test
(Amsler test or MCPT test).
[0407] It can be seen that for subgroups II, III, IV, and V the
MCPT test resulted in a significantly higher percentage of patients
being positively diagnosed, as compared to the percentage of the
patient diagnosed positive when the Amsler grid test was applied to
the same group.
[0408] In the normal retina group (the control group I), the
difference observed between the percentages of individuals showing
positive diagnosis in the MCPT and Amsler grid test was not
statistically significant.
[0409] Testing System Configurations
[0410] It is noted that the testing systems and data analysis
methods disclosed hereinabove may be implemented in different
device and system configuration.
[0411] In accordance with one possible configuration of the system,
the system may be implemented on a computer used at the patient's
home. Such a computer may or may not be connectable to a network as
disclosed in detail hereinabove. A software program may be
installed on a commercially available desktop computer, or portable
computer or any other suitable type of computer. The computer may
be preferably connectable to a network for communicating the test
results to a suitable server. Such a system may have the advantages
of being inexpensive, simple to operate, and being operable at the
patient's home.
[0412] In accordance with another configuration of the test system,
the system may be meant for use at an eye clinic or at an
ophtalmologist's office. Such a system may be implemented on a
powerful computer station or workstation and may also provide the
ophtalmologist or other eye expert with more advanced data analysis
and possibly graphical reports of the test results. Such reports
may advantageously provide data about the possible location of the
retinal lesion(s), an indication of the lesion size or magnitude,
and may possibly include a more detailed report showing the history
of test results of the tested patient.
[0413] It will also be understood that the system according to the
invention may be any suitably programmed computer. Likewise, the
invention contemplates a computer program being readable by a
computer for executing the method of the invention. The invention
further contemplates a machine-readable memory tangibly embodying a
program of instructions executable by the machine for executing the
method of the invention.
[0414] It is noted that while the non-limiting examples of the
testing system disclosed hereinabove and illustrated in FIG. 1
include a display device on the surface of which the various test
patterns and the fixation target are presented to the subject,
other types of systems for administering the test to the subject
may be used which do not include a screen or surface. For example,
in accordance with another embodiment of the present invention the
test patterns and fixation target(s) may be presented to the
subject by using an optical system (not shown) similar to a
scanning laser ophtalmoscope (SLO).
[0415] Reference is now made to FIG. 10 which is a schematic
diagram illustrating a system including a scanning laser device
usable for carrying out an eye test according to another preferred
embodiment of the invention.
[0416] In the system 600, the images of the test patterns and
fixation target(s), and possibly the log-on screen(s) may be
directly projected on the retina of an eye 614 of the test subject
(not shown) by suitably directing a laser beam 612 (schematically
represented by the dashed line labeled 612) through the pupil of
the tested eye 614 and by suitably scanning the laser beam 614
across the retinal surface to form projected images of the test
patterns and/or fixation target(s) at specified locations on the
retinal surface. The system 600 may include a scanning laser device
602. The scanning laser device 602 may be a scanning laser
ophtalmoscope (SLO) device as is known in the art, or any other
device capable of controllably scanning a beam of coherent or
non-coherent light across the retina of an eye. The scanning laser
device 602 may be suitably coupled to a controller unit 604 or to a
computer (not shown) for controlling the operation of the scanning
laser device 602. The controller unit 604 may also be a computer
such as a workstation, or mainframe, or laptop computer or a hand
held or other portable computing device, or a personal computer or
any other type of computing device known in the art. The controller
unit 604 may be coupled to suitable pointing device(s) 610. The
pointing device(s) 610 may be a mouse (not shown), and/or keyboard
connected to a computer or may be any other suitable pointing
device or devices as disclosed hereinabove or as known in the art.
The system 600 may also include one or more output unit(s) 608,
such as, but not limited to, a display, a printer unit, or any
other suitable output device for enabling interaction of a user
with the system 600 and/or for producing hard copy output of test
results or the like. The output unit(s) 608 may be suitably coupled
or connected to the controller unit 604.
[0417] In operation the system 600 may be used for applying any of
the tests disclosed hereinabove but instead of showing the test
pattern, and the fixation targets on a screen 112 of a display
device 115, the images of the test patterns and the fixation
target(s) may be directly projected onto the retina of the tested
eye 614 by the scanning laser device 602 by suitably scanning the
laser beam 612 on the retina of the eye 614. The laser beam 612 may
also be used to project an image of a cursor (similar to the cursor
225 of FIG. 3) directly on the retina of the eye. The movement of
such a projected cursor may be controlled by the one or more of the
pointing devices 610, such as but not limited to a mouse (not
shown).
[0418] Thus, the system 600 may be used to administer to a patient
any of the tests disclosed hereinabove (including but not limited
to the moving line test and the flash test) and to record and store
the responses of the patient including but not limited to the
marking of parts or portions or segments at which distortions or
modifications as disclosed hereinabove were perceived and marked by
the patient. The system 600 may also process the test results using
any of the methods and test criteria disclosed hereinabove to
produce a positive or negative diagnosis. The system 600 may also
be suitably connected to a communication network (such as, but not
limited to the communication network 130 of FIG. 1) and may
communicate with other devices or computers, or the like, over the
communication network.
[0419] It is noted that the laser scanning device 602 may be
replaced or substituted with other scanning devices (not shown)
known in the art which are capable of directing a narrow light beam
having a suitably narrow beam cross-sectional area onto an eye and
scanning the beam controllably across the retina. The light beam
need not be a laser beam but may be any beam of non-coherent light
which may be suitably scanned across a retina with sufficient speed
and resolution.
[0420] It is noted that the construction and operation of laser
scanning ophtalmoscopy devices are well known in the art, are not
the subject matter of the present invention and are therefore not
described in detail herein.
[0421] Assessment of Disease Progression in AMD
[0422] While the testing procedure disclosed hereinabove and
graphically illustrated in FIGS. 4A-4J may produce data which may
be analyzed to determine the presence of retinal abnormalities
(such as, but not limited to, AMD related retinal lesions or
diabetes related retinal lesions, or the like), and to determine
whether a patient tests positive or negative for the presence of
retinal lesions, it may also be desirable to determine the degree
of severity of the detected retinal lesion or lesions and to
determine the stage or progression of disease in the tested patient
or subject.
[0423] AMD patients may generally be clinically divided into groups
such as patients having early AMD without high-risk characteristics
(HRC), patients having early AMD with HRC, patients having late AMD
with geographic atrophy (GA), and patients having advanced AMD with
choroidal neovascularization (CNV). It may be desirable to classify
a patient as belonging to a patient group, such as one of the above
indicated groups without having to resort to a lengthy and
expensive retinal examination by an ophtalmologist.
[0424] As disclosed hereinabove, in a patient having a retinal
lesion, when the patient is presented with a non-distorted test
pattern at a first location on the screen 112 of the display device
115, which causes the image of the test pattern to be projected on
the retina such that part of the projected image of the test
pattern falls on the lesioned region of the retina, the patient may
observe a distortion or abnormal appearance of part of the
perceived image of the test pattern. This type of observed
distortion or other abnormal or modified appearance or change in
the perceived image of the test pattern is referred to as a
pathology related observed distortion (PROD) hereinafter.
[0425] While performing the visual tests disclosed hereinabove,
which included the use of artificially distorted test patterns for
testing the patients reliability in perceiving and/or reporting
these artificially introduced distortions, the inventors of the
present invention have noticed that if an artificially distorted
test pattern is presented at a location on the screen 112 such that
part of the projected image of the test pattern falls on a lesioned
region of the retina, the patient may respond to the presentation
of the test pattern in one of four different types of
responses.
[0426] In the first type of possible response, the patient may
perceive and mark two distortions at two locations of the perceived
image of the artificially distorted test pattern. One perceived
distortion may be associated with the presence of the retinal
lesion and is therefore defined as a PROD and the other perceived
distortion may be associated with the distortion which was
artificially introduced into the displayed artificially distorted
test pattern. The latter type of observed distortion is referred to
as an artificially introduced observed distortion (AIOD)
hereinafter. This first response type is referred to as a "B type"
response hereinafter, to indicate that the patient reported both
the PROD and the AIOD.
[0427] In a second type of possible response, the patient may
perceive and mark only the distortion associated with the presence
of the retinal lesion (only the PROD). This second response type is
referred to as a "P type" response hereinafter, to indicate that
the patient reported only the PROD.
[0428] In a third type of possible response, the patient may
perceive and mark only a distortion associated with the presence of
the distortion which was artificially introduced into the presented
test pattern (only an AIOD). This third response type is referred
to as an "A type" response hereinafter, to indicate that the
patient reported only the AIOD.
[0429] In the fourth type of possible response, the patient may not
observe or mark any distortion at all. This fourth response type is
referred to as an "N type" response hereinafter, to indicate that
the patient did not report any observed distortion.
[0430] Reference is now made to FIG. 11 which is a diagram
schematically illustrating four different possible response types
of the same patient when the patient is presented with a test
pattern including an artificial distortion, such that part of the
projected image of the test pattern falls on a retinal lesion in
the patient's retina.
[0431] The distorted segmented lines 615A, 615B, 615C, and 615D
schematically represent a test pattern presented to the patient as
disclosed in detail hereinabove (by presentation on a display
device, such as for example the screen 112 disclosed hereinabove,
or by direct retinal projection such as for example by using the
system 600 disclosed hereinabove). It is noted that the distorted
segmented lines 615A, 615B, 615C, and 615D schematically represent
the test pattern as presented to the patient (and not the patterns
as observed by the patient).
[0432] The artificial distortions 617A, 617B, 617C, and 617C
comprise displaced segments of the segmented lines 615A, 615B,
615C, and 615D, respectively. The rectangular boxes 619, 620, 621,
and 622, schematically represent regions of the test pattern in
which the patient placed a mark in the various different response
types. It is noted that the boxes 619, 620, 621, and 622 do not
indicate the precise position in which the patient marked an
observed distortion but rather schematically represent the
approximate position at which the patient observed a
distortion.
[0433] The segmented line 615A and the rectangular boxes 619 and
620 superimposed thereon schematically represent a non limiting
example of a response in which the patient reports at least two
observed distortions by marking at least two different regions on
the test pattern in response to the presentation of a test pattern
including an AD 617A. The box 619 schematically represents the
region in which the patient observed a distortion due to a retinal
lesion (a PROD), and the box 620 schematically represents the
region in which the patient observed a distortion due to the
artificial distortion 617A (an AIOD). It is noted that while this
non-limiting schematic example shown illustrates a case in which
the patient marked only two positions in response to the
presentation of the test pattern 615A (one marked position
corresponding to an AIOD and the second marked position
corresponding to a PROD), in other possible responses the patient
may mark more than two positions. For example, the patient may mark
one position in the region of the artificial distortion 617A and
two or more positions in other regions (not shown in FIG. 11) of
the test pattern 615A.
[0434] The segmented line 615B and the rectangular box 621
superimposed thereon schematically represent a non-limiting example
of a response in which the patient reports one or more observed
distortions by marking one or more positions on the display screen,
in response to the presentation of a test pattern 615B including an
AD 617B, as disclosed in detail hereinabove. The box 621
schematically represents the region in which the patient observed a
distortion due to the retinal lesion in the tested eye. In this
type of response the patient did not report an observed distortion
in the region of the artificial distortion 617B.
[0435] The segmented line 615C and the rectangular box 622
superimposed thereon schematically represent a non-limiting example
of a response in which the patient reports a single observed
distortion by marking one position on the display. The box 622
schematically represents the region in which the patient observed a
distortion due to the artificial distortion 617C. In this type of
response the patient does not observe (and therefore does not mark)
a distortion due to the presence of the retinal lesion.
[0436] The segmented line 615D having no boxes superimposed thereon
schematically represents a response in which the patient did not
mark any position on the display, in response to the presentation
of the test pattern because no distortion was observed (and
therefore no distortion was marked) by the patient neither in the
region of the AD 617D presented in the test pattern 615D nor in the
region of the retinal lesion.
[0437] It is noted that the response types illustrated in FIG. 11
are schematic and are given by way of example only, and that the
type of response of a patient to the presentation of a test pattern
may depend, inter alia, on the individual patient being tested, the
shape and type of the presented test pattern, the actual size and
shape of the artificial distortion introduced into the test
pattern, and the type and severity of the retinal lesion in the
retina of the tested eye.
[0438] The inventors of the present invention have found that when
patients are presented with test patterns including artificially
introduced distortions such that part of the projected image of the
test pattern falls on a lesioned region of the retina, there is a
correlation between the retinal lesion type of the patient (i.e.
the severity of the lesion) and the type of patient response
exhibited. Moreover, the type of response also depended on the size
or magnitude of the distortion artificially introduced into the
test patterns presented to the patient.
[0439] By varying the magnitude of the artificial distortion
introduced into the test patterns presented to patients in clinical
experiments it was unexpectedly found that for a particular retinal
lesion, as the artificially introduced distortion in the presented
test pattern becomes larger in magnitude, there is a higher
probability that the patient may preferentially observe and report
the artificially introduced distortion while not observing and
reporting a distortion due to the presence of the retinal
lesion.
[0440] Thus, as empirically and unexpectedly found by the inventors
of the present invention, when patients are presented with test
patterns including artificially introduced distortions such that
part of the projected image of the artificially distorted test
pattern falls on a lesioned region of the retina, the probability
that a patient will respond to the presentation of the artificially
distorted test pattern with the above described third type of
response (observing and reporting only the AIOD) increases as the
magnitude of the distortion increases.
[0441] While the exact psychophysical basis for this phenomenon is
not yet clear, it may appear as if the PROD and the AIOD "compete"
for patient's attention and that there is a higher probability that
a distortion which is larger or more noticeable or more prominent
may be preferentially noticed and reported by the patient, and that
there may be is a smaller probability that the smaller or less
noticeable or less prominent distortion will be noticed and
reported.
[0442] The inventors of the present invention have thus noticed
that by presenting a patient with test patterns having artificially
introduced distortions of various sizes, or amplitudes, or
magnitudes (graded distortions) which are presented to the patient
such that they fall on the lesioned retinal region and by recording
and analyzing the responses of the patient it may be possible to
assess the severity of the patient's lesion or to classify the
patient as belonging to a particular class of clinically defined
disease progression state. For example, in the case of tested AMD
patients it may be possible to classify the tested patients into
groups representing different stages of AMD, as is disclosed in
detail hereinafter.
[0443] Results of "Competition" Experiments
[0444] The competition experiments were performed using
artificially distorted test patterns which were displayed to the
patients on the display screen of a laptop computer. The Laptop
personal computer used was a Dell Latitude laptop computer model
C-600, having a 14.1 inch TFT color screen, but any other suitable
computer or display may also be used.
[0445] It is noted that all the angular dimensions disclosed
hereinbelow are given as cone angles of the visual field of the
subject (when the subject's eye is positioned 50 centimeters from
the screen of the display device, such as the display of laptop
computer used for the test). Each of the test patterns displayed on
the screen included 27 square segments arranged as a segmented
line, the segments were white segments presented on a black
background. Each square segment had the dimensions of 0.26.degree.
by 0.26.degree. (cone angles, when observed at a distance of 50
centimeters from the patient's tested eye as disclosed
hereinabove).
[0446] In the non-distorted (flat) linear test patterns (not
shown), all the segments were linearly arranged and the distance
separating the adjacent ends of two adjacent segments was
0.22.degree.. The distance between the centers of two adjacent
segments is 0.52.degree..
[0447] In the exemplary artificially distorted test patterns used
in the competition experiment, three segments out of the twenty
seven square segments of the test pattern are displaced such that
they are not linearly arranged relative to the other remaining
segments. The remaining twenty four segments are linearly arranged
such that their centers all lie on a straight line (see, for
example, imaginary line 660 of FIG. 12 below).
[0448] Reference is now made to FIG. 12 which is a schematic
diagram illustrating in detail part of a schematic artificially
distorted test pattern used in the competition experiments
performed in accordance with an embodiment of the present
invention.
[0449] In FIG. 12, a part of an artificially distorted test pattern
630 is illustrated. Only ten segments 632, 634, 636, 638, 640, 642,
644, 646, 648, and 650 of the twenty seven segments of the test
pattern 630 are shown.
[0450] The segments 632, 634, 636, 638, 646, 648, and 650 are
arranged such that their centers 632C, 634C, 636C, 638C, 646C,
648C, and 650C, respectively are all disposed along a straight line
660, while the segments 640, 642 and 644 are disposed such that
their centers 640C, 642C and 644C, respectively, are offset from
the line 660 (it is noted that the line 660 is an imaginary line
given only for the purpose of illustrating the arrangement of the
various segments of the test pattern 630, the line 660 does not
form a part of the test pattern 630 and is not shown to the
patient). The seventeen segments included in the test pattern 630
and not shown in FIG. 12 (for the sake of clarity of illustration)
may be disposed on the straight line 660 adjacent to the segment
632, or adjacent to the segment 650. Alternatively some of the
remaining seventeen segments which are not shown in FIG. 12 may be
disposed on the straight line 660 adjacent to the segment 632 and
the rest of the remaining seventeen segments may be disposed on the
straight line 660 adjacent to the segment 650.
[0451] The left and the right sides of each of the twenty seven
segments included in the test pattern 630 are preferably oriented
such that they are perpendicular to the line 660 (it may, however,
also be possible to use other orientations).
[0452] The distance D4 between adjacent segments (represented by
the double headed arrows D4) is 0.22.degree. and the side D5 of all
the square segments of the test pattern 630 is 0.26.degree. (as
indicated above, the values of D4 and D5 represent cone angles,
when observed at a distance of 50 centimeters from the patient's
tested eye as disclosed hereinabove).
[0453] The distorted part of the exemplary test pattern 630
comprises the segments 640, 642, and 644. The centers 640C, 642C
and 644C of the segments 640, 642 and 644, respectively, are
disposed on an (imaginary) half ellipse curve 662 (schematically
represented by the dotted line labeled 662). It is noted that the
half ellipse curve 662, and the center points 632C, 634C, 636C,
638C, 640C, 642C, 644C, 646C, 648C, 650C are shown in FIG. 12 for
explanatory and illustrative purposes only, and do not appear in
the test patterns shown to the patients.
[0454] The distance H between the center point 642C of the segment
642 (the central segment of the three segments 640, 642 and 644
forming the artificial distortion) and the straight line 660 is
defined as the height of the artificial distortion. The distance H
comprises half of the minor axis of an ellipse (not shown in its
entirety) which includes the half ellipse curve 662. The distance
MA is the major axis of such an ellipse.
[0455] For the exemplary test pattern 630 partially illustrated in
FIG. 12, the computer program which generates the test patterns for
display on the screen 112 may compute the positions of the segments
of the test pattern by using the above indicated segment dimensions
(0.26.degree. by 0.26.degree.) and segment spacing (0.22.degree.)
to determine the horizontal coordinate of the center point 642C
(defined as the position of the center point 642C along the
horizontal axis labeled X), and the vertical coordinate of the
center point 642C (defined as the position of the center point 642C
along the vertical axis labeled Y). The computer program may then
compute the vertical coordinates of the center points 640C, and
644C as disposed on the computed half ellipse curve 662. The
horizontal coordinates of the center points 640C, and 644C may be
computed from the computed horizontal coordinate of the center
point 642C and from the known values of D5 and D4.
[0456] Thus, for artificial distortions having different values of
H, the imaginary half ellipse curves may be of different sizes.
[0457] It is noted that while in the exemplary test pattern 630 of
FIG. 12 The major axis MA of the ellipse which includes the half
ellipse curve 662 starts at the center point 638C of the segment
638 and ends at the center point 646C of the segment 646, this need
not be the case for artificial distortions having different values
of the distortion heights H. In other test patterns (not shown) the
computed half ellipse curve (not shown) may intersect the straight
line 660 at points which are different than the center points 638C
and 646C. The exact points of intersection of the (imaginary) half
ellipse curve and the line 660 may depend on the values of D4, D5,
and H. For example, in accordance with one non-limiting example the
computed half ellipse curve (not shown) may intersect the straight
line 660 at a first point (not shown) located between the center
points 636C and 638C and at a second point located between the
center points 646C and 648C.
[0458] It is noted that in EXPERIMENT 1 and EXPERIMENT 2 detailed
below, the computations were rounded to the nearest pixel value to
accommodate for the finite pixel size and resolution on the TFT
screen of the laptop computer used in the test.
[0459] The computer program used for calculating the positions of
the various segments of the test patterns (such as but not limited
to the test pattern 630 partially illustrated in FIG. 12), computed
the positions of the segments 640, 642, and 644 included in an AD
having a height H by using the equation for an elliptical curve as
is known in the art and the known values of D4, and D5. Such a
computation is well known in the art and may be implemented using
many computational methods or program code all of which are known
in the art and are therefore not described in detail
hereinafter.
[0460] Competition Study Details
[0461] The competition study included two different experiments
(EXPERIMENT 1 and EXPERIMENT 2 disclosed hereinbelow). Each
experiment was performed by testing different patient groups. In
both experiments, each tested patient was presented with test
patterns using the flash method disclosed hereinabove with a test
pattern presentation duration of 160 milliseconds.
[0462] The dimensions are given as cone angles wherein each degree
represents 300 micron over the retina. If the subject is 50 cm from
the display screen of the computer, each degree is equivalent to a
length of 0.88 centimeter on the display screen.
[0463] Some of the test patterns were linear (flat) test patterns
as disclosed hereinabove, and did not include an artificial
distortion. Most of the test patterns included a single artificial
distortion.
[0464] Experiment 1
[0465] In this experiment two groups were tested. The first group
included 28 subjects all clinically diagnosed to have normal
retinas (normal group). The second group included 32 subjects
clinically diagnosed to have AMD with high risk characteristics
(AMD with HRC group). All subjects (ranging in age between 50-90
years old) were given a complete eye examination by a retina
specialist prior to performing the tests for the experiment. After
the diagnosis was recorded by the retina specialist each of the
patients was tested using an MCPT adapted for the experiment as
disclosed hereinafter.
[0466] The artificial distortions presented were selected from
artificial distortions (AD) having a height of 0.19.degree.,
0.22.degree. as disclosed hereinabove. Each test pattern had a
dimension of approximately 14.degree.. Half of the test patterns
presented to each patient, were generally horizontally oriented and
the other half were generally vertically oriented, as disclosed
hereinabove. Altogether, the test patterns were adapted to map a
14.degree..times.14.degree. grid on the macula with a 1.degree.
resolution. The fovea of the tested eye was at the center of the
mapped region. The sequence of presentation of the horizontal and
vertical test patterns within a single test was randomly selected.
The sequence of presenting signals with an AD and without an AD was
also randomized. The sequence of presentation of the test patterns
having different heights (heights of 0.19.degree., 0.22.degree.)
was also randomized.
[0467] Each eye was tested by presenting test patterns at thirty
different locations on the display of the laptop computer. Fifteen
locations were horizontally oriented on the display of the laptop
computer and fifteen locations were vertically oriented on the
display of the laptop computer. At each of the thirty different
locations on the display of the laptop computer there were five
randomized presentations of the test patterns, one presentation of
a test pattern with no AD (a flat test pattern), two presentations
of a test pattern including an AD with a height of 0.19.degree.,
and two presentations of a test pattern including an AD with a
height of 0.22.degree.. Altogether, each test included 150
presentations of test patterns to the tested patient's eye.
[0468] In the pair of test pattern presentations including an AD
with a height of 0.19.degree., the position within the test pattern
of the three segments forming the AD was randomly selected, but the
minimal distance between the positions of the AD in the two
presentations was 5.degree. (In other words, if the test patterns
presented at each of the two presentations were to be superimposed
on each other, the distance between the center points of the
central segments of each of the ADs would be equal to or larger
than 5.degree. ).
[0469] Similarly, in the pair of test pattern presentations
including an AD with a height of 0.22.degree., the position within
the test pattern of the three segments forming the AD was randomly
selected, but the minimal distance between the positions of the AD
in the two presentations was 5.degree..
[0470] It is noted that while the random distribution of the
positions of the artificial distortions and the 5.degree. distance
ensures adequate distribution of the positions, other methods for
setting the positions of the artificial distortions in the test
patterns may also be used. For example, in other experiments, a
look up table (LUT) stored in the memory of the laptop computer or
other computer of the computer system 105 was used. The LUT
included a set of positions selected to generate a relatively
uniform distribution of the artificial distortion's position in the
test patterns presented within a test.
[0471] The distribution of the positions were sequentially read
from the LUT and used by the system to determine the position of
the AD within the test patterns. In accordance with other
embodiments of the present invention, satisfactory results may thus
be obtained using such a LUT or a random number generator, or a
pseudorandom generator, or any other algorithm adapted for
generating randomly or non-randomly distributed positions of the
artificial distortions, as long as the sequence of positions cannot
be remembered or otherwise memorized or predicted by the patient or
by the individual being tested.
[0472] The patients were asked to mark the positions at which a
distortion was observed, by using a mouse connected to the Laptop
computer as disclosed in detail hereinabove for the flash test. All
the test data were stored in the laptop computer for further
processing and analysis, including, inter alia, all the settings
and parameters of the presented test patterns, the location and
height of the AD in the artificially distorted test patterns, the
sequence of presentation of the test patterns, and the patients
responses to each test pattern presentations.
[0473] The results were then processed as follows:
[0474] The percentage of marking "flat" test patterns by the
patient P.sub.F was computed according to the equation P.sub.F=100
N.sub.M/P.sub.FT, wherein N.sub.M is the total number of test
pattern presentations in which the patient marked the presence of
one or more observed distortions when presented with a test pattern
having no AD (a flat test pattern), and P.sub.FT is the total
number of test patterns having no AD ("flat" test patterns) which
were presented to the patient in the test.
[0475] In the exemplary, non-limiting, tests performed in
EXPERIMENT 1, the total number of presentations of such flat test
patterns to a patient in a single test of EXPERIMENT 1 is thirty
presentations (P.sub.FT=30).
[0476] The computer further analyzed the position of the markings
by the patient in response to the presentation of test patterns
having an AD, and classified the responses into different
types.
[0477] The computer analyzes the patient responses to detect two
different patient response types. The first patient response type
is a response in which the patient marked one or more positions in
response to the presentation of a test pattern including an AD, and
in which all of the positions marked by the patient were defined as
being due to the presence of a retinal lesion by applying the
criteria disclosed hereinafter and illustrated in FIGS. 13 and 14.
This type of patient response is defined as a P type response
hereinafter.
[0478] The second patient response type is a response in which the
patient marked at least two positions in response to the
presentation of a test pattern including an AD, and in which at
least one of the positions marked by the patient was defined as
being due to the presence of a retinal lesion, and at least one of
the positions was defined as being due to the artificial distortion
present in the test pattern, wherein the definitions were made by
applying the criteria disclosed hereinafter and illustrated in
FIGS. 13 and 14. This type of patient response is defined as a B
type response hereinafter.
[0479] In the first type of patient response, if all the positions
marked by the patient in response to the presentation of a test
pattern including an AD are at a distance equal to or greater than
2.83.degree. from the position of the center of the AD, the
markings are considered to represent a PROD indicating that the
patient observed distortion(s) due to the presence of a real
retinal lesion (or lesions) or abnormality, and the response is
identified and recorded as a P type response.
[0480] In the second type of patient response there are at least
two positions marked by the patient. At least a first position
marked by the patient in response to the presentation of a test
pattern including an AD is at a distance smaller than 2.83.degree.
from the position of the center of the AD. This marking is
considered to be due to an AIOD (assuming that the distortion
marked by the patient is due to the AD). Additionally, at least a
second position marked by the patient in response to the
presentation of the test pattern is at a distance equal to or
greater than 2.83.degree. from the position of the center of the
AD. This second marked position is considered to be due to a PROD
(assuming that the distortion marked by the patient is due to a
retinal lesion). Such a response is identified and recorded as a B
type response.
[0481] Reference is now made to FIGS. 13 and 14 which are schematic
diagrams illustrating in detail the criterion for determining if a
position marked by the patient is due to a PROD indicating the
presence of a retinal lesion or due to an AIOD indicating the
observation of an artificial distortion, in accordance with one
embodiment of the present invention.
[0482] FIG. 13 illustrates part of a horizontal artificially
distorted test pattern 730. The test pattern 730 includes square
segments 732. The segments 732 are arranged such that their centers
(not shown) are disposed on an imaginary straight line 760 (the
imaginary line 760 is not part of the test pattern 730, is not
shown to the patient, and is shown solely for illustrative purposes
to indicate the arrangement of the segments included in the test
pattern 730). The test pattern 730 includes additional segments
which are not shown for the sake of clarity of illustration. The
test pattern 730 is artificially distorted as disclosed
hereinabove. The test pattern 730 includes segments 740, 742, and
744. The centers of the segments 740, 742 and 744 are offset from
the imaginary line 760.
[0483] The dashed line 753 which starts at the center 742C of the
segment 742 is perpendicular to the line 760, and intersects the
line 760 at the point P.sub.C. The point 750 schematically
represents a position marked by the patient (on the display on
which the test pattern 730 is presented) in response to the
presentation of the test pattern 730. The dashed line 755 which
starts at the point 750 is perpendicular to the line 760, and
intersects the line 760 at the point P.sub.M.
[0484] The double headed arrow labeled D6, represents the distance
D6 between the points P.sub.C and P.sub.M along the line 760. If
the distance D6 is equal to or greater than 2.83.degree. (expressed
as the cone angle at a distance of 50 centimeters of the tested eye
from the display screen on which the test pattern 730 is
displayed), the position of the marked point 750 is defined as
being due to a PROD. If the distance D6 is smaller than
2.83.degree., the position of the marked point 750 is defined as
being due to an AIOD.
[0485] FIG. 14 illustrates part of a horizontal artificially
distorted test pattern 830. The test pattern 830 includes square
segments 832. The segments 832 are arranged such that their centers
(not shown) are disposed on an imaginary straight line 860 (the
imaginary line 860 is not part of the test pattern 830, is not
shown to the patient, and is shown solely for illustrative purposes
to indicate the arrangement of the segments included in the test
pattern 830).
[0486] The test pattern 830 includes additional segments which are
not shown for the sake of clarity of illustration. The test pattern
830 is artificially distorted as disclosed hereinabove. The test
pattern 830 includes segments 840, 842, and 844. The centers of the
segments 840, 842 and 844 are offset from the imaginary line
860.
[0487] The dashed line 853 which starts at the center 842C of the
segment 842 is perpendicular to the line 860, and intersects the
line 860 at the point P.sub.C1. The point 850 schematically
represents a position marked by the patient (on the display on
which the test pattern 830 is presented) in response to the
presentation of the test pattern 830. The dashed line 855 which
starts at the point 850 is perpendicular to the line 860, and
intersects the line 860 at the point P.sub.M1.
[0488] The double headed arrow labeled D7, represents the distance
D7 between the points P.sub.C1 and P.sub.M1 along the line 860. If
the distance D7 is equal to or greater than 2.83.degree. (expressed
as the cone angle at a distance of 50 centimeters of the tested eye
from the display screen on which the test pattern 830 is
displayed), the position of the marked point 850 is defined as
being due to a PROD. If the distance D7 is smaller than
2.83.degree., the position of the marked point 850 is defined as
being due to an AIOD.
[0489] Using the above disclosed exemplary (non-limiting) criteria,
a patient's response to the presentation of a test pattern
including an AD in which at least one marked position was defined
as being due to a PROD, is recorded as a P type response, and a
patient's response to the presentation of a test pattern including
an AD in which at least one marked position was defined as being
due to a PROD and at least one other marked position is defined as
being due to an AIOD, is recorded as a B type response.
[0490] It is noted that the criteria illustrated in FIGS. 13 and 14
for classification patient responses as B type or P type responses,
are general criteria which may be applied to all the specific
positions of the artificial distortion within a test pattern, and
to the different possible positions which may be marked by the
patient in response to the presentation of a specific test pattern
including an AD at a particular position. These criteria may be
applied to responses presented at various different locations on
the display device, as disclosed in detail hereinabove, and test
patterns having ADs with different heights
[0491] It is further noted, that while the criteria disclosed
hereinabove for distinguishing between a marked position due to a
PROD and a marked position due to an AIOD are schematically
illustrated for an example (FIG. 13) in which the segments 740,
742, and 744, included in the artificial distortion, are offset
above the line 760 (such an AD is defined as an upward curving AD
hereinafter), the same criteria may also be applied to responses
generated by test patterns (not shown) having an artificial
distortion in which the segments are offset below the line 760
(such an AD is defined as a downward curving AD hereinafter).
[0492] Similarly, the criteria disclosed hereinabove may be
similarly applied for responses to test patterns such as the
exemplary test pattern 830 of FIG. 14 including the segments 840,
842, and 844 of the test pattern 830 of FIG. 14 in which the
segments 840, 842, and 844 of the AD are offset to the left of the
line 860 (such an AD is defined as a left curving AD hereinafter)
and to test patterns (not shown) having an artificial distortion
with segments which are offset to the right of the line 860 (such
an AD is defined as a right curving AD hereinafter).
[0493] In all of the presentations of all the test patterns
including an AD of EXPERIMENT 1, the direction of curvature of the
artificial distortion was randomized. Thus, for horizontal test
patterns including an AD the probability that the AD in the
presented test pattern is an upward curving AD was equal to the
probability that the AD is a downward curving AD (and both of these
probabilities were equal to 0.5). Similarly, for vertical test
patterns including an AD the probability that the AD in the
presented test pattern is a right curving AD was equal to the
probability that the AD is a left curving AD (and both of these
probabilities were equal to 0.5).
[0494] It is, however, noted, that the direction of the curvature
of the AD need not be randomized in the artificially distorted test
patterns which are presented to a patient within a test. Moreover,
it was experimentally discovered, in later experiments, that the
direction of curvature of the distortions observed by patients in
response to the presentation of linear (distorted or non-distorted)
test patterns, depends on the direction of movement of the test
pattern (in tests using the "moving pattern" method disclosed
hereinabove), or on the direction of the presented test pattern
relative to the fixation target (in tests using the flash method
disclosed hereinabove).
[0495] Typically, the PROD observed by the patients was reported to
be curved in the same direction of "movement" of the test pattern
(in tests using the moving pattern method), and in the direction
pointing from the fixation point toward the flashed test pattern
(in tests using the flash method). In other words, the distorted
part of the test pattern as observed by the patient seemed to be
offset (protruding) from the test pattern in the direction of the
"movement" of the test pattern (in tests using the moving pattern
method), and in the direction pointing from the fixation point
toward the flashed test pattern target (in tests using the flash
method).
[0496] Thus, in accordance with another embodiment of the
invention, it may also be possible to use in the tests ADs in which
the distorted part of the test pattern (the AD) presented to the
patient is offset (protruding) from the test pattern in the
direction of the "movement" of the test pattern (in tests using the
moving pattern method), and in the direction pointing from the
fixation point toward the flashed test pattern target (in tests
using the flash method).
[0497] Furthermore, in accordance with yet another embodiment of
the invention, it may also be possible to use in the tests ADs in
which the distorted part of the test pattern (the AD) presented to
the patient is offset (protruding) from the test pattern in a
direction opposite to the "movement" of the test pattern (in tests
using the moving pattern method), or opposite to the direction
pointing from the fixation point toward the flashed test pattern
target (in tests using the flash method).
[0498] After determining the response types for all of the
patient's responses evoked by the presentation of test patterns
including an AD, the computer further calculates the following
parameters. For all of the test patterns including an AD with the
same height, the computer computes the values R.sub.H, and B.sub.H,
wherein R.sub.H is the percentage of responses classified as P type
responses out of the total number of test patterns including an AD
with a height H which were presented to the patient, and wherein
B.sub.H is the percentage of responses classified as B type
responses out of the total number of test patterns including an AD
with a height H which were presented to the patient.
[0499] For example, if the patient was presented with 60 test
patterns having an artificial distortion with a height
H=0.22.degree. (represented as degrees of the cone angle for a
distance of 50 centimeters of the tested eye from the display on
which the test patterns are presented), and 6 responses out of all
the patient's responses to the presentation of these 60 test
patterns were classified as P type responses, then R.sub.0.22=10%.
For the same patient presented with the above indicated 60 test
patterns having an artificial distortion with a height
H=0.22.degree., if three responses out of all the patient's
responses to the presentation of these 60 test patterns were
classified as B type responses, then B.sub.0.22=5%.
[0500] The computer then further calculated the value of the
competition grade C.sub.H for an artificial distortion having a
height H, wherein C.sub.H=R.sub.H+B.sub.H.
[0501] For example, for the above exemplary test of the same
patient for which R.sub.0.22=10% and B.sub.0.22=5%, the value of
C.sub.0.22 is C.sub.0.22=10%+5%=15%. Thus, for this particular test
of the above exemplary (hypothetical) patient, the competition
grade for an artificial distortion having a height of 0.22.degree.,
is 15 percent.
[0502] After performing various different empirical calculations
based on the analysis of results of the patients tested in
EXPERIMENT 1, the following criteria were selected for determining
if the patient belongs to the group with normal retina, or belongs
to the group having AMD with HRC, based on the results of the test
patterns having ADs with a height of 0.19.degree. (it is noted that
the data from the results of the test patterns having ADs with a
height of 0.22.degree. were not used for establishing these
criteria):
[0503] A patient belongs to the group with high risk
characteristics AMD (AMD with HRC group) if at least one of the
following two conditions is satisfied:
[0504] 1) P.sub.F>10%
[0505] 2) C.sub.0.19>7%
[0506] wherein P.sub.F and C.sub.0.19, are as defined in detail
hereinabove.
[0507] If none of the above two criteria is satisfied, the patient
belongs to the group having normal retinas (normal group).
[0508] When these classification criteria are applied to the test
results of all the patients tested in EXPERIMENT 1, the results
were as indicated in TABLE 1 below.
2 TABLE 1 Patients Patients ophtalmologically ophtalmologically
diagnosed as diagnosed as having having Normal AMD with HRC retinas
Total Patients which 28 2 30 satisfy at least one of the
conditions: P.sub.F > 10% C.sub.0.19 > 7% Patients which 4 26
30 do not satisfy any of the conditions: P.sub.F > 10%
C.sub.0.19 > 7% Total 32 28 60 Calculated sensitivity 87.5%
Calculated specificity 93% P < 0.001
[0509] Experiment 2
[0510] In this experiment, two groups were tested. The first group
included 43 subjects clinically diagnosed to have AMD with high
risk characteristics (AMD with HRC group). The second group
included 20 subjects clinically diagnosed to have CNV. All subjects
(in the age range of 50-90 years old) were given a complete eye
examination by a retina specialist prior to performing the tests
for the experiment. After the diagnosis was recorded by the retina
specialist each of the patient was tested using an MCPT adapted for
the experiment as disclosed hereinafter.
[0511] The artificial distortions presented were selected from
artificial distortions (AD) having a height of 0.19.degree.,
0.22.degree., and 0.28.degree. as disclosed hereinabove. Each test
pattern had a dimension of approximately 14.degree.. Half of the
test patterns presented to each patient, were generally
horizontally oriented and the other half were generally vertically
oriented, as disclosed hereinabove. Altogether, the test patterns
were adapted to map a 14.degree..times.14.degree. grid on the
macula with a 1.degree. resolution. The fovea of the tested eye was
at the center of the mapped region. The sequence of presentation of
the horizontal and vertical test patterns within a single test was
randomly selected. The sequence of presenting signals with an AD
and without an AD was also randomized. The sequence of presentation
of the test patterns having different heights (selected from
heights of 0.19.degree., 0.22.degree., and 0.28.degree.) was also
randomized, as disclosed hereinafter.
[0512] In all of the presentations of all the test patterns
including an AD of EXPERIMENT 2, the direction of curvature of the
artificial distortion was randomized. Thus, for horizontal test
patterns including an AD the probability that the AD in the
presented test pattern is an upward curving AD was equal to the
probability that the AD is a downward curving AD (and both of these
probabilities were equal to 0.5). Similarly, for vertical test
patterns including an AD the probability that the AD in the
presented test pattern is a right curving AD was equal to the
probability that the AD is a left curving AD (and both of these
probabilities were equal to 0.5).
[0513] Each eye was tested by presenting test patterns at thirty
different locations on the display of the laptop computer. Fifteen
locations were horizontally oriented on the display of the laptop
computer and fifteen locations were vertically oriented on the
display of the laptop computer. At each of the thirty different
locations on the display of the laptop computer there were three
(3) randomized presentations of the test patterns, one presentation
of a test pattern with no AD (a flat test pattern), each of the two
other presentations of a test pattern at the location included an
AD. Altogether, each test included 90 presentations of test
patterns to the tested patient's eye.
[0514] The height of the AD in each of these two remaining
presentations was randomly selected from the heights 0.19.degree.,
0.22.degree., and 0.28.degree. without repetition (without
repetition means herein that the two ADs presented at the same
location were always of different heights). It is noted that since
only two (out of three possible) different heights of AD were used
in the test patterns presented at the same location and
orientation, the data for each specific location and orientation of
a test pattern did not include all possible AD heights.
[0515] In the two test pattern presentations including an AD, the
position within the test pattern of the three segments forming the
AD was randomly selected, but the minimal distance between the
positions of the AD in the two presentations was 5.degree., as
explained in detail for EXPERIMENT 1 hereinabove.
[0516] The patients were asked to mark the positions at which a
distortion was observed, by using a mouse connected to the Laptop
computer as disclosed in detail hereinabove for the flash test. All
the test data were stored in the laptop computer for further
processing and analysis, as disclosed in detail for EXPERIMENT 1
hereinabove.
[0517] The results of EXPERIMENT 2 were then processed as follows.
The computer analyzed the position of the markings by the patient
in response to the presentation of test patterns having an AD, and
classified the responses as follows. Turning back to FIGS. 13 and
14, for horizontal test patterns if the distance D6 (FIG. 13) is
smaller than 2.83.degree., the position of the marked point 750 is
defined as being due to an AIOD. Similarly, for vertical test
patterns, if the distance D7 (FIG. 14) is smaller than
2.83.degree., the position of the marked point 850 is defined as
being due to an AIOD.
[0518] If, in response to the presentation of a test pattern
including an AD, all the positions marked by the patient are
defined to be due to an AIOD using the definition as disclosed
hereinabove, the response is classified as an A type response
(indicating that all of the positions marked by the patient are
considered to be due to an AIOD).
[0519] After determining the response type for all of the patient's
responses evoked by the presentation of test patterns including an
AD, the computer further calculated the following parameters. For
all of the test patterns including an AD with the same height H,
the computer computed the value A.sub.H, wherein A.sub.H is the
percentage of responses classified as A type responses out of the
total number of test patterns presented to the patient which
contained an AD with a height H.
[0520] For example, if the patient was presented with twenty (20)
test patterns having an artificial distortion with a height of
H=0.28.degree. (represented as degrees of the cone angle for a
distance of 50 centimeters of the tested eye from the display on
which the test patterns are presented), and five (5) responses out
of all the patient's responses to the presentation of these twenty
test patterns were classified as A type responses, then
A.sub.0.28=25%.
[0521] After performing various different empirical calculations
based on the analysis of results of the patients tested in
EXPERIMENT 2, the following criterion was selected for determining
if the patient belongs to the group having CNV, or belongs to the
group having AMD with HRC, based on the results of the test
patterns having ADs with a height of 0.28.degree. (it is noted that
the data from the results of the test patterns having ADs with
heights of 0.19.degree. and 0.22.degree. was not used for
establishing the criterion below):
[0522] A patient belongs to the group with CNV if
A.sub.0.28<75%
[0523] If A.sub.0.28.gtoreq.75%, the patient belongs to the group
having high risk characteristics AMD (AMD with HRC group).
[0524] When this patient classification criterion is applied to the
test results of all the patients tested in EXPERIMENT 2, the
results were as indicated in TABLE 2 below.
3 TABLE 2 Patients Patients ophtalmologically ophtalmologically
diagnosed as diagnosed as having having CNV AMD with HRC Total
Patients for 18 6 24 which A.sub.0.28 < 75% Patients for 2 37 39
which A.sub.0.28 .gtoreq. 75% Total 20 43 63 Calculated sensitivity
90% Calculated specificity 85% P < 0.001
[0525] It will be appreciated by those skilled in the art that the
specific classification criteria disclosed hereinabove for
classifying patients as belonging to specific different AMD disease
progression groups, are given by way of example only and are not
intended to limit the scope of the invention. Other different
criteria may be empirically determined and used by modifying or
fine tuning the parameters of the test or the parameters of the
test patterns used in the test. Systematically varying one or more
of the parameters of the test or of the test patterns used therein
may be therefore used to fine tune or improve or optimize the test
to yield better or improved classification criteria. Such
systematic variations are known to those skilled in the art, and
are therefore not described in detail hereinafter.
[0526] It is noted that while in the non limiting examples of the
embodiments of the competition method of the present invention
which are described in EXPERIMENT 1 and EXPERIMENT 2 disclosed
hereinabove, the data used for distinguishing or classifying the
tested individuals into different groups was taken from a group of
test patterns having an AD of a certain selected height (the group
of data obtained using test patterns with ADs having a height
H=0.19 in EXPERIMENT 1 and the group of data using test patterns
with ADs having a height H=0.28 in EXPERIMENT 2), this is not
mandatory and other embodiments of the present invention may use
different or additional classification criteria based on processing
of the results obtained from the presentation of test pattern
groups having different artificial distortion heights.
[0527] For example, in accordance with other possible embodiments
of the invention it may be possible to use classification criteria
which use data from more than one group of test patterns having ADs
of different heights. For example, using the data obtained in
EXPERIMENT 2, one may use a classification criterion that
classifies a patient as having AMD with HRC if A.sub.0.28.gtoreq.m
and A.sub.0.22.gtoreq.n, and classifies the patient as having CNV
if A.sub.0.28<m and A.sub.0.22<n, wherein m and n are
percentage values which are empirically determined to give desired
or acceptable levels of specificity and sensitivity.
[0528] Moreover, other classification criteria may be used which
may use the values of A.sub.H computed from results of two or three
groups of test patterns presenting ADs with H=0.28, H=0.22 and
H=0.19. For example, one may used weighted results in the
classification criterion.
[0529] An exemplary (non-limiting) form of such criteria using
weighted results may be, the patient may be classified as having
AMD with HRC if:
(.alpha.A.sub.0.28+.beta.A.sub.0.22+.gamma.A.sub.0.19).gtoreq.q
[0530] and as having CNV if:
(.alpha.A.sub.0.28+.beta.A.sub.0.22+.gamma.A.sub.0.19)<q
[0531] wherein .alpha., .beta., and .gamma. are empirically
determined weighting factors, and q is an empirically determined
number.
[0532] The above criteria and other empirically determined criteria
may be used to implement the classification of the tested
individuals into groups having different clinical stages of AMD (or
other retinal or choroidal pathologies).
[0533] It will thus be appreciated that while the results of
EXPERIMENT 1 and EXPERIMENT 2 demonstrate that it is possible to
classify patients into groups having different clinical stages of
AMD by using the responses of the tested patients to the
presentation of test patterns having artificial distortions with a
single AD height (for example, the test patterns having H=0.19 of
EXPERIMENT 1 or the test patterns having H=0.28 of EXPERIMENT 2) it
may also be possible to use within a single test patterns having
ADs with more than one height or amplitude and to process the
patient responses data to classify the tested patients with proper
modification of the classification criteria used.
[0534] It is noted that while the "competition" method of using
different graded distortion magnitudes for assessing the severity,
or the magnitude, or the dimensions of a retinal or choroidal
lesion may be based on the use of artificial distortions included
in the segmented test patterns having different graded distortion
heights as disclosed hereinabove, other types of graded artificial
distortions having various magnitudes or amplitudes or size may
also be used in the present invention.
[0535] Furthermore, while the competition tests disclosed
hereinabove included the use of linear and distorted segmented test
patterns, many other types of test patterns may also be used for
implementing embodiments of the present invention, the test
patterns may include but are not limited to, non-segmented
(continuous) lines like any of the types disclosed hereinabove with
respect to the MCPT test, and may include but are not limited to
straight lines, curved lines, straight or curved lines having a
distorted portion or part, or the like. The parts of the test
patterns which are distorted may be curved like part of an
elliptical curve, or parabolic curve, or an undulating curve, or
any other suitable curve shape that may mimic the appearance of a
distortion perceivable by a patient having a retinal lesion.
Additionally, the distorted part of the test pattern (irrespective
whether the test pattern is segmented or non-segmented) may be
configured to have a linear shape, such as for example, a
triangular distortion shape, or the like. Moreover, the segments
(or alternatively the continuous part of the test pattern)
comprising the distortion may be arranged as any desired type of
distortion having any suitable shape.
[0536] In another example, in accordance with other embodiments of
the present invention it may be possible to use artificial
distortions with a triangular shape (not shown) having graded
heights of the triangle-like distortion, or curved artificial
distortions in which the segments of the artificial distortion are
arranged along non-linear curves other than an ellipse and having
graded curve parameters. Such non-linear curves may include but are
not limited to parabolas, irregular curves, and curves having
multiple extremum points.
[0537] Thus, the shapes, curvature, dimensions and magnitudes of
the artificial distortions disclosed hereinabove, illustrated in
the drawing figures and used in the experiments, are given by way
of example only and are not obligatory to practicing the invention.
It is therefore noted that many other types of artificial
distortions and test patterns having other different parameters may
also be used in practicing the invention all of which are
considered to be included within the scope of the present
invention.
[0538] It is noted that while the distortion type used in
EXPERIMENT 1 and EXPERIMENT 2 is symmetrical (with respect to the
minor axis of the half ellipse curve 662 used for determining the
position of the center points 640C and 644C of the segments 640 and
644, respectively, illustrated in FIG. 12), the distorted part of
the curve need not necessarily be symmetrical. Thus, the distortion
types usable in different embodiments of the present invention
(irrespective of whether the test pattern is segmented or
non-segmented) may be a symmetrical distortion or a non-symmetrical
distortion.
[0539] For example, possible embodiments of the methods and test
patterns of the invention it may include, inter alia, embodiments
in which one or more of the following test parameters may be
varied: the number of segments in the test patterns, the segment
size and/or shape (for example, circular shapes may be used instead
of square segments), the segment shape, the distance between
segments, the size and/or shape and/or amplitude, and/or the
longitudinal dimension of the artificial distortion along the test
pattern (the width of the distortion), and/or curvature of the
artificial distortion (including the curvature degree and/or
curvature direction of the artificial distortion), the color and/or
luminosity, of the test patterns and/or of the background on which
the test patterns are displayed or presented to the patient, the
sequence of presentation of the test patterns (including fixed
sequences, random sequences, and pseudo-random sequences of test
pattern presentations), the positioning of the AD within the test
pattern, the AD magnitudes or amplitudes used in the test, the
duration of presentation of the test pattern to the patient in the
flash method, the method of position marking used by the patient
for reporting the position of the observed distortions, the number,
type, and sequence of the test patterns included in a test, or the
like.
[0540] It will be appreciated by those skilled in the art that if
one or more of the parameters of the test patterns or of the
artificial distortions used are modified, the methods and criteria
used for processing the data and for analyzing the results may have
to be adapted to the changes made.
[0541] For example, in accordance with one possible embodiment of
the present invention, the artificial distortions used may be
graded according to their width or longitudinal dimension along the
test pattern. Returning briefly to FIGS. 12-14, the artificial
distortions may also graded by graded changing of the longitudinal
dimension of the artificial distortion along the test pattern. For
example, the distance MA (FIG. 12) may be varied in a graded manner
in different ADs instead of the distance H (FIG. 12). In such a
case it may be necessary to adapt the distance from the center of
the AD which is used as a criterion to decide if a position marked
by the tested individual is assumed to be due to the artificial
distortion (or defined as an AIOD as disclosed in detail
hereinabove).
[0542] For example, in accordance with one possible embodiment of
the invention, one may use three different ADs in a test. All the
ADs used have the same distance H (such as, but not limited to,
0.22.degree.), but each AD may have one of three possible values of
the distance MA, such as, but not limited to, 1.92.degree.,
2.62.degree., and 3.32.degree.. This may be achieved, for example,
by displacing three, five, and seven segments of the test pattern
630, respectively, vertically above the line 660 of FIG. 12, using
a suitable half ellipse curve, or by suitably increasing the
distance D4 between the segments 638, 640, 642, 644, and 646
without changing the distance between each of the segments 640 642
and 644 and the straight line 660, or by any suitable combination
of the above exemplary methods, or by any other method for
increasing the width or longitudinal dimension (on the axis labeled
X of FIG. 12) of the AD along the test pattern 630.
[0543] In such a case, it may be desired to modify the criterion of
distance of the marked position from the center point of the AD for
each of the three different graded forms of the AD. For Example,
the criterion distance for ADs having MA=1.92.degree. may be
2.83.degree. as disclosed above, while the criterion distance used
for ADs having MA=2.62.degree., and MA=3.32.degree. may be
3.53.degree., and 4.23.degree., respectively (all cone angles
assuming a distance of approximately 50 centimeters from the tested
eye and the screen 112).
[0544] Similarly, if any other parameters of the test patterns are
changed, or the type and/or density of the grid which they may form
on the retina if they were all simultaneously projected thereon are
changed, it may or may not be necessary to suitably change or adapt
the processing of the data, such as, but not limited to, the
proximity criteria used for processing the responses to pairs of
test patterns projected, or the like.
[0545] Furthermore, it will be appreciated by those skilled in the
art that while the shape and dimensions of the ADs used in the
experiments may be computed or determined using mathematical
methods for constructing the test patterns including ADs (such as
in the exemplary embodiment for computing of the position of the
center points of the segments 640 642 and 644 of FIG. 12 using a
half ellipse curve computation), it may also be possible to use
test patterns having ADs which are empirically found to give a
satisfactory sensitivity and selectivity in classification studies
similar but not identical to the studies disclosed in EXPERIMENT 1
and EXPERIMENT 2 above.
[0546] In such studies one may possibly test many different types
of arbitrarily or non-computationally created artificial
distortions in order to empirically define a set of ADs which
yields satisfactory classifications of AMD stages. Such artificial
distortions may be constructed to differ one from the others in
shape or dimensions or color or any other single or multiple
characteristics of the ADs.
[0547] For example, if one uses within the same test an
ellipsoidaly shaped AD, a triangularly shaped AD and a
rectangularly shaped AD, and it is found that each of these ADs has
a different efficacy as a competing stimulus, such AD combinations
may also be practically used in the classification tests of the
present invention.
[0548] It is noted that it may also be possible to use in the tests
of the present invention ADs in which the AD may include
arbitrarily selected changes in any visually perceivable
characteristic(s) of the test pattern or of parts thereof. Such
changes may be in the color or brightness or blurriness or in any
other suitable perceivable characteristic of the test pattern or
part thereof, as long as the used sets of AD have been empirically
tested and proven to give satisfactory performance is clinical
tests in humans with eye disease.
[0549] Moreover, while the precise mechanism underlying the
competition phenomenon disclosed herein is not known, it may be
possible that when the patient is simultaneously presented with
multiple stimuli, there is a "competition for attention". It may
therefore be possible that when a patient is simultaneously exposed
to multiple sensory stimuli there is a certain probability that the
more prominent or noticeable or larger stimulus will be
preferentially noticed (and therefore preferentially reported by
the patient.
[0550] When the two stimuli are of the same sensory modality, such
as for example in the cases in which a test pattern including an AD
is projected on a retinal position having a retinal lesion, the
perceived distortion which is of a larger magnitude or which is
more noticeable or perceived as larger or more prominent may be
statistically preferentially perceived by the patient (and
therefore may be statistically preferentially reported by the
patient).
[0551] It may therefore be possible, in accordance with additional
embodiments of the present invention to use in the "competition
method" other different types of sensory stimuli for competing with
the PROD, including but not limited to, visual stimuli, auditory
stimuli, somatosensory stimuli (including but not limited to
various temperature stimuli, touch stimuli, pressure stimuli, itch
stimuli, or the like), kinesthetic stimuli such as moving various
different limbs or digits or other organs, various different pain
stimuli, or any other suitable sensory stimuli having various
different modality.
[0552] Such sensory stimuli of various differing sensory modalities
are generally referred to as competing stimulus (CS) hereinafter.
In the present application, the definition of a competing stimulus
is any sensory stimulus which may be delivered or applied or
presented to a tested patient and which may affect the probability
that the patient will report a PROD when a test pattern is
presented to the patient at a location such that the image of the
test pattern is projected on a lesioned retinal or choroidal
region.
[0553] The different sensory stimuli may be administered or applied
or presented to the patient before and/or simultaneously with the
presentation of the visual test patterns disclosed hereinabove in
detail or with the presentation of other suitable different visual
test patterns. These different sensory stimuli may possibly
function as "distracting stimuli" or as "competing stimuli" that
compete for patient's attention for obtaining results which are
similar (though not necessarily identical) to the results of the
competition experiments using visual AD's as disclosed
hereinabove.
[0554] Additionally, one or more of the parameters of these
additional sensory stimuli may be varied systematically or graded
in different presentations of the stimuli. By varying one or more
of the parameters of the additional sensory stimuli presented with
or before or after the primary visual test patterns (such as, but
not limited to the linear segmented test pattern 322 of FIG. 3, or
the test patterns 382 of FIG. 5B disclosed hereinabove), and by
recording and analyzing the patient's responses, it may be possible
to empirically establish classification criteria for diagnosing a
patient as belonging to a group with a defined stage of the
disease. For example, using such criteria it may be possible to
distinguish between different clinically distinguishable stages of
AMD (such as but not limited to the different AMD stages disclosed
hereinabove in EXPERIMENT 1 and EXPERIMENT 2).
[0555] It will be appreciated by those skilled in the art that such
criteria may be different than the empirical criteria disclosed
hereinabove for the use of artificially distorted test patterns
disclosed for EXPERIMENT 1 and EXPERIMENT 2 hereinabove.
[0556] Thus, in accordance with one exemplary embodiment of the
invention, the distracting stimulus may be an auditory stimulus.
For example, the patient may perform a modified version of an MCPT
test in which an auditory stimulus may be delivered to the patient
before, during, or after the presentation of a visual test pattern.
The auditory stimulus may be delivered to the patient by using
earphones (not shown) or suitable speakers, or the like. The
auditory stimulus may be in the form of a click, or a beep, or a
pure sine wave having a finite duration, or a telephone-like
ringing, or any other suitable type of auditory stimulus known in
the art. The auditory signal may be delivered to the patient
before, during, or after the presentation of a test pattern (the
test pattern may or may not include an AD) to a tested eye of the
patient. If the test pattern is presented at a location such that
the patient may perceive a PROD, the delivery of the auditory
stimulus may distract the patients attention. By repeating the
presentation of the test pattern together with the auditory
stimulus, varying (grading) one or more of the parameters of the
auditory stimulus delivered, and recording the patient's responses
to the presentation of the test stimuli it may be possible to
analyze the competition of the auditory stimulus with the PROD and
to empirically determine classification criteria for various AMD
stages, or for other stages of other different retinal pathologies
or diseases.
[0557] The parameters of the auditory stimulus that may be varied
(graded) in different presentations of test patterns may be but is
not limited to one or more of the amplitude, duration, frequency
(or frequency range and content for stimuli including a range of
frequencies), or waveform of the auditory stimulus. Additionally,
it may be possible to use a group of different auditory stimuli
which are empirically selected on the basis of having different
psychophysical efficacy as distracting or competing stimuli.
[0558] Experiment 3
[0559] This experiment was performed to test different types of
auditory stimuli for their efficacy as competing stimulus (CS), in
accordance with yet another embodiment of the present invention.
The study included three tested individuals having normal retinas
(as ascertained by full ophtalmological examination as disclosed
hereinabove). Each one of the tested individuals was subjected to
five different tests (designated as tests 1-5). Each of the tests
1-5 included presenting a total of thirty eight (38) test patterns
to the tested individual using the flash method as disclosed in
detail hereinabove. The test patterns were segmented straight lines
as disclosed in detail hereinabove for EXPERIMENT 2. Of the thirty
eight test patterns presented in each test, nineteen test patterns
were vertical and the other nineteen test patterns were horizontal.
Each of the 38 test patterns included an AD having a height of
0.12.degree., as disclosed hereinabove. The position of the AD
within the test pattern was randomized using an LUT as disclosed
hereinabove.
[0560] Reference is now made to FIG. 15 which is a schematic
diagram illustrating a system useful for carrying out an eye test
to detect and or assess an eye disease using auditory competing
stimuli in accordance with another embodiment of the present
invention. The system 305 is similar to the system 105 disclosed
hereinabove, except that the screen 212 of the display device 115
was a touch sensitive screen, and the tested subject 100 marked the
positions of the ADs or other perceived differences on the screen
212 using his finger instead of using the mouse 125, and that the
system 305 also included a stereophonic headphones set 211.
[0561] For the duration of the tests, the tested subject 100 was
wearing the headphones set 211. In all the tests performed in
EXPERIMENT 3 and EXPERIMENT 4, the headphones set 211 were model
MDR-305 stereophonic headphones, commercially available from Sony
Corp., Japan.
[0562] It is, however noted, that any other suitable sound source
may be used for performing the method of the present invention,
including but not limited to monoaural sound sources, single
earphones worn by the tested individual, various types of
loudspeakers such as one or more loudspeakers which are built into
or form part of the computer system 105 or 305, one or more
loudspeakers positioned in the room in which the individual 100 is
being tested, or any other single or multiple sound sources known
in the art.
[0563] The headphones set 211 were suitably connected to the line
output of the sound card (not shown) installed in the computer 110.
The computer 110 in this study was a Dell Latitude Laptop computer,
model C600 commercially available from Dell Computer Corporation
U.S.A, and the operating system was the Microsoft Windows 2000
Professional (Version 5.0.2195 Service Pack 1, Built 2195)
commercially from Microsft Corporation, U.S.A. During all tests the
distance between the screen 212 and the tested eye was
approximately 50 centimeters.
[0564] The sound card used for the production of the CS was the
onboard sound card hardware provided with the Dell Latitude C600
laptop computer (ESS Maestro PCI audio, from Engineering Software
Services companies Fl, U.S.A). All Sound measurements were
performed using the "Environmental noise measurement system"
software (version 3.1.1.2) commercially available from Yoshimasa
Electronic Inc., Japan, using the sound pressure level (SPL)
measurement mode.
[0565] For measuring the sound pressure levels, a model MIC111
Maxxtro omni-directional microphone was used (commercially
available from Gembird Electronics Ltd., Hong Kong). The microphone
had a frequency response of 15 Hz-13 KHz, an impedance of >2,200
Ohms, and a sensitivity of 58 dB.+-.2 dB. The microphone was
connected to the line-in audio input jack of the laptop computer
and the microphone was placed between the two earphones at a
distance of approximately 3 millimeters from each earphone.
[0566] In two of the tests conducted (TEST 1 and TEST 3) no sound
was used during the test. These tests served as control tests.
[0567] In TEST 2, TEST 4 and TEST 5, sound was used as a competing
stimulus (CS). The test pattern presentation duration was 160
milliseconds as disclosed hereinabove. The duration of the sound
used as the auditory CS was 900 milliseconds. The auditory CS
started at the time of presentation of the test pattern and ended
740 milliseconds after the end of the presentation of the test
pattern on the screen 212.
[0568] Three different auditory CS types were used. In TEST 2 the
auditory CS was a sound having an increasing pitch (defined as
sound type 1). Sound type 1 was obtained by playing through the
headphones set 211 the sound file "SOUND20.WAV" taken from the
Windows XP.RTM. sound library. The file was played as the auditory
CS through the headphones set 211 at a sound pressure level of 40
dB.
[0569] In TEST 4 the auditory CS was a synthesized telephone
ring-like sound (defined as sound type 2) Sound type 2 was obtained
by playing through the headphones set 211 the sound file
"RINGIN.WAV" taken from the Windows XP.RTM. sound library. The
intensity of the auditory CS was 40 dB.
[0570] In TEST 5 the auditory CS was a synthesized sound of
electronic drums which was panned as if moving from the right side
to the left side in space, by changing the sound intensity in the
left and right earphones of the headphones set 211 (defined as
sound type 3). Sound type 3 was obtained by playing through the
headphones set 211 the sound file "TestSnd.wav" taken from the
Windows XP.RTM. sound library. The sound pressure level of the
auditory CS was 40 dB.
[0571] In all tests the subject 100 was requested to mark all the
perceived distortions in all the test patterns as disclosed in
detail hereinabove. The tested subject marked the perceived
distortions by touching the touch sensitive screen 212 with his
finger at the position at which a distortion or a difference or
deviation from a reference segmented straight line was
perceived.
[0572] The following parameters were recorded for analysis. A
response in which the presented AD was detected and correctly
marked (according to the criteria as disclosed hereinabove for
EXPERIMENTS 1 and 2) is recorded as "FOUND".
[0573] A response in which the presented AD was not detected by the
tested subject 100 (according to the criteria as disclosed
hereinabove for EXPERIMENTS 1 and 2) is recorded as "NOT
FOUND".
[0574] A response in which the position marked by the tested
subject 100 was far from the location of the center of the AD (the
criterion used here was when the position marked was at a cone
angle of more than 2 degrees from the center of the AD) is referred
to as "REAL", indicating that the tested subject did observe a
distortion or difference which is assumed not to be due to the
presence of the AD presented in the test pattern.
[0575] In analyzing the results, a "competition index" C.sub.I was
defined as follows,
C.sub.I=F/(NF+R)
[0576] Wherein,
[0577] C.sub.I is the competition index for sound type I (for
example, C.sub.1 is the competition index for sound type 1, C.sub.2
is the competition index for sound type 2, etc.),
[0578] F represents the number of test pattern presentations in the
test for which a "FOUND" response was recorded,
[0579] NF represents the number of test pattern presentations in
the test for which a "NOT FOUND" response was recorded, and
[0580] R represents the number of test pattern presentations in the
test for which at least one "REAL" response was recorded.
[0581] Higher values of C.sub.I indicate a higher percentage of
correct identifications of the artificial distortions, while lower
values of C.sub.I indicate a lower percentage of correct
identifications of the artificial distortions.
[0582] The raw data of all test results in EXPERIMENT 3 is shown in
TABLE 4 below.
[0583] In TABLE 4, the first column lists the tested subject number
(test subjects 1, 2, and 3). The second column indicates the test
number. For the column group labeled "Found", the sub-column
labeled H represents the number of horizontal test patterns for
which a "Found" result was recorded in the test indicated in the
appropriate row, the sub-column labeled V represents the number of
vertical test patterns for which a "Found" result was recorded in
the test indicated in the appropriate row, and the sub-column
labeled T represents the total number of test patterns (horizontal
and vertical) for which a "Found" result was recorded in the test
indicated in the appropriate row.
[0584] Similarly, for the columns group labeled "Not Found", the
sub-column labeled H represents the number of horizontal test
patterns for which a "Not Found" result was recorded in the test
indicated in the appropriate row, the sub-column labeled V
represents the number of vertical test patterns for which a "Not
Found" result was recorded in the test indicated in the appropriate
row, and the sub-column labeled T represents the total number of
test patterns (horizontal and vertical) for which a "Not Found"
result was recorded in the test indicated in the appropriate row,
and for the columns group labeled "Real", the sub-column labeled H
represents the number of horizontal test patterns for which a
"Real" result was recorded in the test indicated in the appropriate
row, the sub-column labeled V represents the number of vertical
test patterns for which a "Real" result was recorded in the test
indicated in the appropriate row, and the sub-column label T
represents the total number of test patterns (horizontal and
vertical) for which a "Real" result was recorded in the test
indicated in the appropriate row.
4TABLE 4 Tested Subject and Test "Found" "Not Found" "Real" R + F/
Number H V T H V T H V T NF (NF + R) 1. test 1 19 12 31 0 3 3 0 4 4
7 4.43 test 2 14 14 28 1 1 2 4 4 8 7 4.00 test 3 17 14 31 0 0 0 2 5
7 10 3.10 test 4 14 14 28 0 0 0 5 5 10 10 2.80 test 5 17 14 31 1 1
2 1 4 5 7 4.43 2. test 1 15 14 29 1 5 6 3 0 3 9 3.22 test 2 16 9 25
3 10 13 0 0 0 13 1.92 test 3 14 16 30 1 1 2 4 2 6 8 3.75 test 4 10
10 20 5 7 12 4 2 6 18 1.11 test 5 2 8 10 13 10 23 4 1 5 28 0.36 3.
test 1 12 15 27 4 1 5 3 3 6 11 2.45 test 2 10 8 18 7 5 12 3 5 8 20
0.90 test 3 14 13 27 5 3 8 0 3 3 11 2.45 test 4 14 10 24 5 6 11 0 3
3 14 1.71 test 5 12 14 26 6 3 9 1 2 3 12 2.17
[0585] The columns labeled R+NF and F/(NF+R) show the values of
these expressions (calculated as disclosed in detail hereinabove)
for the test indicated in the appropriate row.
[0586] Summary of the Results of Experiment 3
[0587] The raw results shown in TABLE 4 above were further pooled
and averaged as shown below.
[0588] 1. The value of the pooled competition index for all the
tests with no auditory competing stimulus was calculated as
follows, the results from TEST 1 and TEST 3 (the tests with no
auditory competing stimuli) of all three test subjects (tested
subjects 1, 2, and 3), and the computed Q.sub.I values for all six
tests were averaged. The resulting mean was 3.23.+-.0.77
(Mean.+-.S.D.; n=6 tests).
[0589] 2. The value of the pooled competition index for all the
tests in which auditory competing stimuli was presented was
calculated as follows: The results from TEST 2, TEST 4 and TEST 5
(the tests with auditory competing stimuli) of all three test
subjects (tested subjects 1, 2, and 3), and the Q.sub.I values for
all nine tests were averaged. The resulting mean was 2.16.+-.1.38
(Mean.+-.S.D.; n=9 tests).
[0590] The results for each one of the tests (TEST 1-TEST 5) were
also averaged by averaging the competition index calculated for all
three tested subject as follows:
[0591] 3. The value of the calculated competition indexes for TEST
1 (no auditory competing stimulus) was averaged for all three
tested subjects (tested subjects 1, 2, and 3). The computed Q.sub.1
values for the tests were averaged. The resulting mean was
3.37.+-.0.77 (Mean.+-.S.D.; n=3 tests).
[0592] 4. The value of the pooled competition index for all the
tests in which the presented auditory competing stimuli number was
Sound type 1 was calculated as follows: The results from TEST 2
(the test in which the auditory competing stimulus was sound type
1) for all three test subjects (tested subjects 1-3) were averaged,
and the mean Q.sub.I value for TEST 2 in all three subjects was
2.27.+-.1.1 (Mean.+-.S.D.; n=3 tests).
[0593] 5. The value of the calculated competition indexes for TEST
3 (no auditory competing stimulus) was averaged for all three
tested subjects (tested subjects 1, 2, and 3). The computed Q.sub.I
values for the tests were averaged. The resulting mean was
3.10.+-.0.67 (Mean.+-.S.D.; n=3 tests).
[0594] 6. The value of the pooled competition index for all the
tests in which the presented auditory competing stimuli number was
Sound type 2 was calculated as follows: The results from TEST 4
(the test in which the auditory competing stimulus was sound type
2) of all three test subjects (tested subjects 1-3), and the
Q.sub.I values for all three tests were averaged. The resulting
mean was 1.88.+-.0.86 (Mean.+-.S.D.; n=3 tests).
[0595] 7. The value of the pooled competition index for all the
tests in which the presented auditory competing stimuli number was
Sound type 3 was calculated as follows: The results from TEST 5
(the test in which the auditory competing stimulus was sound type
3) of all three test subjects (tested subjects 1-3), and the
Q.sub.I values for all three tests were averaged. The resulting
mean was 2.32.+-.2.04 (Mean.+-.S.D.; n=3 tests).
[0596] To summarize, the results of EXPERIMENT 3 demonstrate that
auditory stimuli of different types may reduce the ability of the
tested individual to perceive and/or report an artificial
distortion in a visually presented test pattern. The mean
competition index for all tests without an auditory competing
stimulus (no sound), is 3.23.+-.0.77 (Mean.+-.S.D.; n=6 tests) as
compared to a lower value of 2.16.+-.1.38 (Mean.+-.S.D.; n=9 tests)
in the tests in which a competing auditory stimulus was presented
to the tested subject. It may also be seen from the above presented
results that different types of auditory stimuli having different
characteristics may have different efficacy in competing against
the presented visual stimuli (the AD). For example, from the three
different types of auditory stimulus, sound type 2 was the most
efficient in competing with sound types 1 and 3 have lower efficacy
than sound type 2. This was consistent for all three tested
subjects.
[0597] While the physiological or psychophysical basis for this
phenomenon is not presently clearly understood, it may be possible
that the different types of sound have different efficacy as
distracting stimuli in distracting the attention of the tested
subject from the visual stimuli presented in the test. It may
therefore be concluded that sounds having various different
characteristics may be used for assessing or quantifying the
severity of retinal or choroidal lesions or abnormalities.
[0598] Experiment 4
[0599] This experiment was performed to test the ability of a
specific form of auditory competing stimulus presented at different
sound intensities to compete in a graded manner with visual stimuli
for patient attention in tests requiring the reporting of
artificially introduced distortions in visual test patterns.
[0600] The same three individuals from EXPERIMENT 3 were tested.
The tests in experiment 4 were performed as described in detail for
EXPERIMENT 3 hereinabove. Each of the three tested individuals
having normal retinas were given three consecutive tests (TEST 6,
TEST 7 and TEST 8). Each test included 38 test patterns (19
vertical and 19 horizontal) performed as disclosed for TEST 4 of
EXPERIMENT 3, except that the sound pressure levels used were
different than the sound intensity used in TEST 4. The auditory CS
was Sound type 2, obtained by playing through the headphones set
211 the sound file "RINGIN.WAV" taken from the Windows XP.RTM.
sound library.
[0601] In all the tests included in EXPERIMENT 4 (tests 6, 7 and
8), the duration and the timing of the auditory CS was as disclosed
in detail for TEST 4 of EXPERIMENT 3.
[0602] In TEST 6 the sound pressure level of the CS was 35 dB, in
TEST 7 the sound pressure level of the CS was 45 dB, and in TEST 8
the sound pressure level of the CS was 50 dB.
[0603] The raw test results for EXPERIMENT 4 are given in TABLE 5
below, (the column arrangement and abbreviations in TABLE 5 are as
described for TABLE 4).
[0604] The competition index Q.sub.I was calculated for all tests
(as given in the rightmost column of TABLE 5). For each test the
computed Q.sub.I values from all three tested individuals were
averaged and the results are summarized in TABLE 6 below.
5TABLE 5 Tested Subject and Test "Found" "Not Found" "Real" R + F/
Number H V T H V T H V T NF (NF + R) 1. test 6 17 13 30 0 4 4 2 2 4
8 3.75 test 7 16 13 29 3 5 8 0 1 1 9 3.22 test 8 14 10 24 4 9 13 1
0 1 14 1.71 2. test 6 15 8 23 3 5 8 1 6 7 15 1.53 test 7 10 9 19 7
9 16 2 1 3 19 1.00 test 8 8 10 18 10 8 18 1 1 2 20 0.90 3. test 6
16 15 31 2 2 4 1 2 3 7 4.43 test 7 13 8 21 4 7 11 2 4 6 17 1.24
test 8 11 10 21 6 8 14 2 1 3 17 1.24
[0605]
6 TABLE 6 Sound Pressure averaged Q.sub.1 value TEST level for all
tested subjects NUMBER of Auditory CS Mean .+-. S.D. (n = 3) TEST 6
35 dB 3.24 .+-. 1.514 TEST 7 45 dB 1.82 .+-. 1.221 TEST 8 50 dB
1.28 .+-. 0.409
[0606] The results of EXPERIMENT 4 indicate that when a given sound
type (specifically, sound type 2) is presented to the tested
individuals at different sound pressure levels during the visual
testing as described hereinabove, the computed competition index is
a function of the sound pressure level of the auditory competing
stimulus. As is shown in TABLE 5 and TABLE 6 above, there is a
direct correlation between sound pressure level and the ability of
the tested individual(s) to correctly report the positions of the
AD in the test patterns (in accordance with the specific criteria
used in the tests). Thus, while the physiological or psychophysical
basis for this phenomenon are not presently clearly understood, it
may be possible that the different intensities of sound have
different efficacy as distracting stimuli in distracting the
attention of the tested subject from the visual stimuli presented
in the test. It may therefore be concluded that sounds having
graded intensity values may be used for assessing or quantifying
the severity of retinal or choroidal lesions or abnormalities.
[0607] Reference is now made to FIG. 16 which is a schematic block
diagram illustrating a system for applying visual tests and
competing sensory stimuli to a test subject, in accordance with an
embodiment of the present invention.
[0608] The system 650 may include a visual test-pattern presenting
unit 660 for presenting test patterns to a test subject (not
shown), and a competing sensory stimuli generating unit 662 for
presenting the tested subject competing sensory stimuli. The visual
test-pattern presenting unit 660 and the competing sensory stimulus
generating unit 662 may be suitably operatively coupled to a
controller/processor unit 664. The controller/processor unit 664
may control and coordinate the presenting of visual and competing
sensory stimuli to the test subject by the visual test-pattern
presenting unit 660 and the competing sensory stimuli generating
unit 662, respectively.
[0609] The system 650 may further include one or more user input
device(s) 666, one or more output device(s) 668 and a storage unit
670 for storing data. The user input device(s) 666, the output
device(s) 668, and the storage unit 670 may be suitably connected
to the controller/processor unit 664.
[0610] The visual test-pattern presenting unit 660 may be any type
of unit or device suitable for presenting visual test patterns to a
test subject as disclosed hereinabove and as known in the art. For
example, the visual test-pattern presenting unit 660 may be a
computer with a coupled display device, such as a computer, or a
desktop computer or a laptop computer or a workstation or any other
device known in the art that is capable of controllably presenting
test patterns to a test subject. For example, the visual
test-pattern presenting unit 660 may be any of the systems 105 of
FIG. 1 or the system 600 of FIG. 10, or any other type of display
or screen based device known in the art, or any other type of
device capable of scanning a beam of light into an eye, including,
but not limited to, SLO devices and head up display (HUD) devices
known in the art.
[0611] If the visual test-pattern presenting unit 660 includes a
surface or a screen capable of displaying images of the test
patterns (and fixation target, if required), the display may be any
type of suitable display known in the art, including but not
limited to a cathode ray tube (CRT) type display device, a liquid
crystal display (LCD), a light emitting diode (LED) or organic
light emitting diode (OLED) based display device, a plasma display
device, a mechanical or micro-electromechanical (MEMS) based
display device, or the like. Generally, any suitable device that
may be adapted for displaying or projecting images on a surface or
directly projecting images into an eye, or of controllably scanning
a beam of light into an eye is considered to be within the scope of
the present invention.
[0612] Generally, the competing sensory stimulus generating unit
662 may be any type of device or system or unit which is capable of
delivering sensory stimuli to the individual which is being tested
using the system 650.
[0613] For example, in accordance with one possible embodiment of
the invention, the competing sensory stimulus generating unit 662
may be a system or device for delivering auditory stimuli (sound
stimuli) to the tested individual, such as but not limited to a
sound source suitably coupled to controller/processor unit 664. In
the exemplary embodiment disclosed in detail hereinabove and
illustrated in FIG. 15, the competing sensory stimulus generating
unit 662 may include a computer add-on sound card (not shown in
FIG. 15) installed in the computer 110 and coupled to the pair of
headphones 211. It will be appreciated by those skilled in the art,
that many other types of sound sources may be used as is disclosed
in detail hereinabove or as is known in the art. Thus, any suitable
type of sound source which may be used to generate sound stimuli in
a controlled manner may be used in the present invention.
[0614] In accordance with other possible embodiments of the present
invention, the competing sensory stimulus generating unit 662 may
be any suitable device for delivering tactile sensory stimuli, or
any suitable device for delivering other types of somatosensory
stimuli capable of competing with the visual stimuli delivered by
the system 650 to the tested individual, such as, but not limited
to, nociceptive stimuli, tactile stimuli, thermal stimuli
(temperature change related stimuli), pressure stimuli, mechanical
stimuli delivered to the tested individual (such as, but not
limited to, mechanically delivered vibrations applied to the skin
of the tested individual), or any other suitable stimuli having
other suitable sensory modalities.
[0615] For example, in accordance with one possible embodiment of
the invention, the competing sensory stimulus generating unit 662
may include an electrically powered vibrator (not shown) or probe
which is mechanically coupled or attached or put in contact with
the skin of the tested individual and which is suitably connected
to the controller/processor unit 664. For example, the vibrator may
be a small flat piezoelectric transducer which put in contact with
the skin of the tested individual is attached to the skin (of the
finger, or the hand, or any other suitable body part of the tested
individual) using a band or strap of flexible material (not shown).
In operation, vibrations having different vibration amplitudes or
frequencies may be delivered to the skin of the tested individual
before, during or after the presentation of the test patterns as
disclosed hereinabove. Many other types of vibrating devices or
probes or other graded mechanical stimulus delivering devices may
also be adapted for used with the present invention, as is well
known in the art.
[0616] In accordance with another possible embodiment of the
invention, the competing sensory stimulus generating unit 662 may
be an electrically operated heating element, or Peltier device,
(not shown in detail) which may thermally coupled to the skin and
which may be used to controllably deliver heat or cold stimuli to
the skin of the tested individual before, during or after the
presentation of the test patterns as disclosed hereinabove.
Additionally, a suitable laser device may be used to deliver
heating pulses having different graded parameters to an area of the
skin of the tested individual which may be used as thermal
competing stimuli.
[0617] In accordance with another possible embodiment of the
invention, the competing sensory stimulus generating unit 662 may
be an electrically operated heating element, or Peltier device (not
shown in detail) which may thermally coupled to the skin and which
may be used to controllably deliver thermal (heat or coldness)
stimuli to the skin of the tested individual before, during or
after the presentation of the test patterns as disclosed
hereinabove.
[0618] It is noted that the methods and devices for delivering
various graded or non-graded) sensory stimuli to a patient or test
subject are well known in the art, are not the subject matter of
the present invention, and are therefore not disclosed in detail
hereinafter. Generally, the competing stimuli (CS) of the method
and systems of the present invention may be delivered to the test
subject using any suitable device known in the art for controllably
delivering such sensory stimulation to a tested individual.
[0619] The user input device(s) 666 may be one or more user
interface devices which may be used by the tested individual to
provide input to or to interact with the system 650 during the
performing of tests. The input device(s) 666 may include but are
not limited to, a computer pointing device, a mouse, a keypad, a
keyboard, a touch sensitive screen (usable in conjunction with a
suitable stylus or with a finger, or the like), a touch sensitive
pad, other types of touch sensitive devices, a light pen, a stylus,
a joystick, and any suitable combination of the above listed input
devices, or any other suitable type of input device known in the
art.
[0620] The output device(s) 668 may include but are not limited to
a display device for providing instructions or images, or test
patterns to the tested individual, a printer for providing hardcopy
of the test results or of test schedules or of patient demographic
or other data (including, but not limited to, raw test results,
and/or processed test results, and or diagnostic information, in
graphic form or alphanumeric form or any other symbolic form).
[0621] The storage unit(s) 670 of the system 650 may be any
suitable type of storage known in the art and usable for storing
data and/or programs for operating the system 650 or the
controller/processor unit 664, and or raw or processed test results
and the like. For example, the storage unit(s) 670, may include one
or more solid state memory devices such as, but not limited to,
RAM, DRAM, SDRAM ROM, RDRAM, FLASH, and compact FLASH memory
devices, or combinations thereof. The storage unit(s) 670 may also
include other types of storage devices having fixed or removable
storage media, such as, but not limited to, magnetic drives,
optical drives, magnet-optical drives, solid state drives having
fixed or removable solid state media, holographic drives or storage
devices, or the like.
[0622] It is noted that while the system 650 is shown is a specific
configuration illustrated in FIG. 16, many other configurations
thereof may be implemented. For example, while the
controller/processor unit 664 of FIG. 16 is illustrated as a
separate unit, the controller/processor unit 664 may be included as
part of the visual test-pattern presenting unit 660 or of the
visual test-pattern presenting unit 660. In other embodiments of
the system 650, the visual test-pattern presenting unit 660 and/or
the visual test-pattern presenting unit 660 may include additional
controllers and/or processors (not shown in detail in FIG. 16).
Furthermore, the system 650 may be (optionally) suitably connected
via one or more communication line(s) 672 to other computers (not
shown) or to a computer network such any of the networks disclosed
hereinabove (including but not limited to, a LAN, a PAN, a WAN, a
VPN or the like).
[0623] Thus, while in accordance with one embodiment of the present
invention, the system 650 or the other systems disclosed in the
application, may be a standalone system, such as a system which may
be used in the office of an eye physician or in a clinic of an
ophtalmologist or other eye specialist, for testing individuals,
for patient screening, or for other diagnostic or treatment
follow-up purposes, or for any other suitable. In this embodiment
the testing and processing of the data, and the reporting of the
test results may all be performed by the system.
[0624] In accordance with other embodiments of the invention, the
systems 650, or 105 may be a simple and relatively inexpensive
system for home use by the patient. In such embodiments it may be
possible to process the data by the system and produce an output
for the patient as disclosed in detail hereinabove, or it may be
possible to send the processed test results or the raw data itself
using any the network types disclosed hereinabove. The analyzed
test results or the raw data (or both) may be communicated to a
supervising physician's office or clinic or to a central data bank
in a hospital or in an or to any other suitable health service
provider, or the like.
[0625] Additional Possible Types of Competing Stimuli
[0626] An additional type of usable competing stimulus is a visual
stimulus. In accordance with another embodiment of the invention, a
visual test pattern is presented to the patient (such as but not
limited to the segmented test patterns disclosed in EXPERIMENT 1
and EXPERIMENT 2 using the flash method of presenting the test
pattern, as disclosed in detail hereinabove) and another visual
stimulus is displayed on the same display device at a different
location than the location of the test pattern. For example, the
additional (distracting or competing) visual stimulus may be a
visual pattern such as but not limited to a known symbol or
character or the like such as for example, the letter C, or the
number 5, or a graphic symbol (such as, for example, the symbol ),
or any other suitable visual pattern or alphanumeric symbol or
character or graphic sign, or the like. This additional visual
stimulus is referred to as a "distracting visual stimulus" (DVS)
hereinafter.
[0627] In accordance with another embodiment of the present
invention, the DVS may be superimposed on part of the test pattern
or may be separately presented on the display device. The DVS may
or may not be presented synchronously with the test pattern. For
example, if the test pattern is presented using the above described
flash method, the DVS may be flashed together with the test pattern
for the entire duration of the presentation of the test pattern, or
may be presented before, and/or during, and/or after the
presentation of the test pattern. Thus, the duration of the
presentation of the DVS may be equal to, or smaller than, or larger
than the duration of the presented test pattern.
[0628] In accordance with another embodiment of the present
invention, the time period of the presentation of the test pattern
may fully or partially overlap the time period of the duration of
the DVS. The time period of the presentation of the DVS may,
however, not overlap the duration of presentation of the test
pattern, but may precede the time of presentation of the test
pattern and may terminate before or simultaneously with the
beginning of the presentation of the test pattern.
[0629] In accordance with another embodiment of the present
invention, the DVS may also be any other type of visual pattern
such as a picture or digital photograph or digital representation,
or image of a human face, or any other suitable object. The
distracting capability of the DVS may be related to the type or
nature of the object presented in the DVS.
[0630] In accordance with another embodiment of the present
invention, the DVS may be a part of the test pattern. For example,
if the test pattern is a segmented test pattern (such as but not
limited to the test pattern 382 of FIG. 5B), the DVS may include
one or more of the segments of the segmented test pattern 382.
[0631] In a non-limiting example, the DVS may be one or more
segments of the test pattern 382 which may be colored yellow, while
all the rest of the segments of the test pattern 630 may be colored
white (all the segments of the test pattern 682 may be presented on
a black background). Thus, the different color of the segments
which are included in the DVS may distract the attention of the
patient or compete for attention with a PROD which may be observed
by the patient when the test pattern 382 is presented at a location
on the screen 112 such that at least part of the test pattern is
projected on a retinal lesion. Similar to the results of the
competition of the ADs introduced into the test pattern in
EXPERIMENT 1 and EXPERIMENT 2, the presentation of this type of DVS
(comprising yellow colored segments) may decrease the probability
that the patient will report the PROD.
[0632] It is noted that while the exemplary embodiment disclosed
hereinabove uses segmented lines, the use of different colored DVS
may also be applied to any other type of usable test pattern, such
as but not limited to continuous lines (including straight or
curved lines), or any other suitable type of test pattern. For
example, if the test pattern is a straight continuous line, the DVS
may be a differently colored portion of the straight line.
[0633] In accordance with another embodiment of the present
invention, the part of the test pattern the DVS may only partially
overlap the test pattern. For example, if the test pattern used is
similar to the test pattern 382 of FIG. 5B, the DVS may be a short
segmented line (not shown) which is generally orthogonal to the
test pattern 382 and has six yellow segments. One segment of the
DVS may overlap one segment of the test pattern 382 such that the
segment which is common to the DVS and the test pattern is
yellow.
[0634] It is noted that the color yellow is arbitrarily chosen as a
non-limiting example and that any other suitable color may be used
in other embodiment of the invention.
[0635] Reference is now made to FIGS. 17A-17K which are schematic
diagrams illustrating exemplary forms of various different test
patterns and competing visual stimuli which may be used in
accordance with some embodiments of the present invention.
[0636] Each of FIGS. 17A-17K illustrates a test pattern and a
competing visual stimulus which may be used as a DVS as they may
appear on part of the screen 112 of the system 105 of FIG. 1 or as
may be projected on an area of interest of a tested retina. For the
sake of clarity of illustration, the fixation target is not shown
in FIGS. 17A-17K, but may be any type of suitable fixation target
as disclosed and illustrated in detail hereinabove.
[0637] In the example illustrated FIG. 17A, the test pattern is a
horizontal straight line 860 and the competing visual stimulus used
as a DVS is a graphic symbol 960 schematically resembling a human
face.
[0638] In the example illustrated FIG. 17B, the test pattern is a
horizontal segmented straight line 862 and the competing visual
stimulus used as a DVS is a triangular pattern 962.
[0639] In the example illustrated FIG. 17C, the test pattern is a
horizontal straight line 864 and the competing visual stimulus used
as a DVS is a rectangular pattern 964.
[0640] In the example illustrated FIG. 17D, the test pattern is a
horizontal straight line 866 and the competing visual stimulus used
as a DVS includes three dots 966A, 966B, and 966C arranged in a
triangular pattern 966.
[0641] In the example illustrated FIG. 17E, the test pattern is a
straight horizontal dotted line 868 and the competing visual
stimulus used as a DVS is a pattern 968 shaped as the numeral
"5".
[0642] In the example illustrated FIG. 17F, the test pattern is a
vertical straight line and the competing visual stimulus used as a
DVS is a pattern 970 comprising three concentric rings 970A, 970B,
and 970C.
[0643] In the example illustrated FIG. 17G, the test pattern is a
vertical straight line and the competing visual stimulus used as a
DVS is a slanted short line 972 which is inclined at an angle to
the vertical line 872.
[0644] In the example illustrated FIG. 17H, the test pattern is a
vertical straight line 874 and the competing visual stimulus used
as a DVS is an arrow-like pattern 974.
[0645] In the example illustrated FIG. 17I, the test pattern is a
horizontal straight line 876 and the competing visual stimulus used
as a DVS is a circular pattern 976 which is superimposed on the
line 876.
[0646] In the example illustrated FIG. 17J, the test pattern is a
vertical straight line 878 and the competing visual stimulus used
as a DVS comprises a gap 978 (a missing part) in the line 878.
[0647] In the example illustrated FIG. 17K, the test pattern is a
horizontal straight line 880 and the competing visual stimulus used
as a DVS comprises a part 880A of the line 880. The part 880A may
have a color which is different than the color of the remaining
parts of the line 880. Alternatively, the part 880A may have
another visually perceivable characteristic, such as brightness,
luminance, or the like, which is different than the same
characteristic of the remaining parts of the line 880.
[0648] In performing the tests, the test patterns may be projected
at different locations on the tested retina, using any of the test
methods disclosed hereinabove (including, but not limited to the
"flash" and the "moving line" methods). The visual patterns which
are being used as competing visual stimuli or DVS may be projected
on the retina before, during, or after the presentation of the test
patterns as disclosed in detail hereinabove. In different
repetitions one or more characteristics or parameters of the
competing visual stimulus may be varied in order to change it's
efficacy as a competing or distracting stimulus.
[0649] For example one or more characteristic of the competing
stimulus may be changed, including, but not limited to, the size,
the color, the brightness, the hue, or the distance of the DVS from
the test pattern may be varied. In specific forms of competing
stimuli some types of characteristics may be changed. For example,
for the competing stimulus 966 of FIG. 17D, the distance between
the dots 966A, 966B, and 966C may be increased or decreased, but
many other different types of changes may be made to change the
competing efficacy or distracting efficacy of the competing
stimulus or DVS.
[0650] Generally, the types and spatial arrangement of the test
patterns and the competing visual stimuli, and the changing of the
parameters or characteristics of the competing visual stimulus may
be empirically determined by performing suitable clinical studies
to test the efficacy of various different forms of visual (or
other) competing stimuli (graded or non-graded) as competing
stimuli. Such tests may be performed on test subjects having normal
healthy retinas, by using ADs inserted into the test patterns and
empirically assessing the competing efficacy of the competing
stimuli as disclosed hereinabove. Alternatively or additionally,
the tests may be performed on patients clinically diagnosed to have
certain stages of AMD and various degrees of retinal or choroidal
lesions.
[0651] It is also noted that the different competing stimuli used
within a test need not be quantitatively graded. Turning briefly to
FIG. 17C, while changing the size of the rectangular pattern 964
may suitably change it's efficacy as a competing stimulus or DVS,
it may also be possible to use competing stimuli having qualitative
differences in the test. For example it may be possible to use a
red rectangular competing stimulus of a first size and a yellow
rectangular competing stimulus having a second different size as
competing visual stimuli within the same test, provided one pattern
having a specific combination of characteristics is empirically
determined to have a competing efficacy or distracting efficacy
which is different than another of the used competing stimuli
having a different combination of characteristics.
[0652] It is noted that because the efficacy of different competing
visual stimuli may differ significantly, it may be also possible to
mix different types of stimuli in the same test. For example in
accordance with one possible embodiment of the invention, it may be
possible to use the graphic symbol 960 (FIG. 17A, the rectangular
pattern 964 (FIG. 17C) and the arrow-like pattern 974 (FIG. 17H) in
the same test depending on their efficacy as competing visual
stimuli or distracting stimuli. Thus, such combinations of
different competing stimuli may be used to assess the degree, or
size, or severity of a retinal or choroidal lesion or abnormality,
based on their empirically tested efficacy.
[0653] It is noted that many possible variations and permutations
of the DVS of the present invention are possible which are included
within the scope of the present invention. A few non-limiting
examples may include, but are not limited to, DVS which comprise
one or more blinking segments of the test pattern, or one or more
blinking portions of a continuous test pattern, or any other visual
patterns or images which may or may not partially overlap the test
pattern and which may have different colors than the test pattern,
or a gray level, or a luminosity, or brightness which is different
than the gray level, or the luminosity, or the brightness of the
test pattern, respectively, or any suitable combinations of the
above differences.
[0654] It will be appreciated by those skilled in the art that
combinations of the above properties of the DVS may also be
possible. For example, the DVS may include one or more segments of
the test pattern which may have a different color than the color of
the remaining segments of the test patterns and may also blink
(turn on and off at a desired frequency).
[0655] Thus, DVS types usable in the present invention are not
limited to the exemplary embodiments described herein but may be
any suitable type of visual stimulus which is effective in
affecting the probability that the patient will report a PROD when
a test pattern is presented to the patient at a location such that
the image of the test pattern is projected on a lesioned retinal
(or choroidal) region.
[0656] By repeating the presentation of the test pattern and the
DVS, varying (grading) one or more of the parameters or
characteristics of the DVS, and recording the patient's responses
to the presentation of the test stimuli it may be possible to
analyze the competition of the DVS with the PROD and to empirically
determine classification criteria for various AMD stages, or for
other stages of other different retinal pathologies or
diseases.
[0657] The parameters of the DVS that may be varied (or graded) in
different presentations of test patterns may be, but are not
limited to, one or more of the color (or colors) of the DVS, the
brightness of the DVS (the absolute DVS brightness or the
brightness of the DVS relative to the brightness of the test
pattern), the luminosity of the DVS, the gray level of the DVS, the
frequency of blinking of the DVS, the size or dimensions or shape
of the DVS, the distance of the DVS from the test pattern, the
inclination of the DVS relative to the test pattern, or
combinations thereof. Additionally, it may be possible to use a
group of different DVS types which are empirically selected on the
basis of having different psychophysical efficacy as distracting
stimuli.
[0658] Another lesion grading method may be implemented, in
accordance with another embodiment of the present invention by
introducing a controlled degree of "visual noise" into the test.
For example, while the background on which the test patterns are
presented may be a uniform black background, the background may
also be a variable background. For example, one or more of the
visual parameters the individual pixels (or of pixel groups) on the
screen 112 which form the background for the test pattern may be
varied randomly, or pseudo-randomly, or periodically, or
aperiodically. The pixel parameters which may be varied may
include, but are not limited to, the intensity, color, luminosity,
gray level, hue (for pixel groups or single composite pixels), and
the like.
[0659] The "visual noisiness" of the background may be varied
between different presentations of test patterns, thus, effectively
allowing graded degrees of visual noise which may have different
efficacy in changing the probability that the patient will report a
PROD when a test pattern is presented to the patient on the noisy
background at a location such that the image of the test pattern is
projected on a lesioned retinal region.
[0660] Such graded degrees of background visual noise may be
implemented, inter alia, by changing the frequency of the variation
of the pixel or pixel group parameters, by changing the range of
pixel parameter values between which the pixels are allowed to vary
(for example, by increasing or decreasing the range of values
within which the pixels' brightness, or the pixels' color, or the
pixels' gray level is allowed to vary), or by modifying the number
and/or the distribution of the background pixels that are varied
(such as, for example, by changing the percentage of background
pixels for which one or more visually detectable parameters are
allowed to vary, or by suitably changing or modifying the values of
other suitable parameters in a way which may affect the
characteristics of the background noise).
[0661] Thus, the noisy background types usable in the present
invention are not limited to the exemplary embodiments described
herein but may be any suitable type of visual background variation
or degree which is effective in affecting the probability that the
patient will report a PROD when a test pattern is presented to the
patient at a location (on the noisy background) such that the image
of the test pattern is projected on a lesioned retinal region.
[0662] By repeating the presentation of the test pattern, while
varying (grading) one or more of the parameters of the background,
and recording the patient's responses to the presentation of the
test stimuli on different backgrounds it may be possible to analyze
the competition of the noisy background with the PROD and to
empirically determine classification criteria for various AMD
stages, or for other stages of other different retinal pathologies
or diseases.
[0663] It is noted that generally it may be possible to subject the
tested individual to a competing sensory stimulus (of any
experimentally effective sensory modality) before, or during, or
after the presentation of the test pattern to the tested
individual, or before and during the presentation of the test
pattern to the tested individual, or during and after the
presentation of the test pattern to the tested individual, or
before and during and after the presentation of the test pattern to
the tested individual. The selection of the timing and duration of
the presentation of the CS may be determined, inter alia, by the
type and sensory modality of the CS, the method of presentation of
the test pattern, the type and duration of the test patterns, and
other practical considerations. It will be appreciated that the
specific timing and duration parameters of the competing auditory
stimuli of EXPERIMENT 3 and EXPERIMENT 4 above are given by way of
example only and many other variations of the timing and duration
of the auditory competing stimulus or of any other types of
auditory, or visual competing stimuli or other sensory modality of
competing sensory stimuli may be used in various implementations of
the method of the present invention.
[0664] It is noted that while the experiments disclosed herein
demonstrate the use of competing stimuli having graded stimulus
parameter(s), the invention is not limited to the use of competing
stimuli which are graded. The experiments with auditory competing
stimuli disclosed herein demonstrate that while grading the sound
intensity may be used to vary the competing efficacy of the CS,
other non-graded changes in the stimulus may be effectively used to
vary the competing efficacy of the CS (such as, but not limited to
differences the spectral content of the sound). Moreover, in
accordance with yet another embodiment of the present invention, it
may be possible to used competing stimuli having different sensory
modalities in the same test.
[0665] For example, it may be possible to perform the testing of
the present invention by using within the same test visual
competing stimuli and auditory competing stimuli. In a non limiting
example, the system 305 of FIG. 15 may be used to deliver auditory
competing stimuli (as disclosed in detail hereinabove to the tested
individual 100 together with some of the repetitions of the
displaying of the test patterns (such as, but not limited to, the
segmented straight line test patterns disclosed hereinabove and
illustrated in FIGS. 3, 5B, and 5E) while in some other repetitions
of the displaying of the test patterns of the same test, the test
patterns may include visual competing stimuli, such as, but not
limited to, artificial distortions (such as for example any of the
artificial distortions shown in FIG. 5J, or partially shown in FIG.
6, or the like) or, alternatively, the test patterns may be
presented together with other competing visual stimuli (such as but
not limited to, any of the DVS or competing visual stimuli
disclosed herein and illustrated in the examples of FIGS. 17A-17K,
or the like). Since each of the different competing stimuli
(including but not limited to, any type of AD or DVS and auditory
competing used within the same test) may have a different competing
efficacy, it is possible to empirically determine the specific
efficacies of such competing stimuli in experiments in known
clinically diagnosed patient groups and to establish suitable
diagnostic criteria for use in screening or testing patients as
disclosed in detail hereinabove for experiments using graded
artificial distortions only.
[0666] In an exemplary mixed modality test one may use two
repetitions of a presentation of a straight segmented line together
with exposing the tested individual to sound type 2 (as disclosed
in detail in EXPERIMENT 4 above) and two repetition of presenting
an artificially distorted test pattern (such as, but not limited
to, the artificial distortion having a height of 0.19.degree. of
EXPERIMENT 1 above) at each tested retinal location. When using
competing stimuli of different sensory modalities within the same
test, the criteria for establishing the clinical stage of AMD (or
of other types of eye disease) by empirically determining the
diagnostic criteria in experiments using known clinically diagnosed
patient groups, as disclosed in detail hereinabove in EXPERIMENT
1.
[0667] The determination of suitable diagnostic criteria (for
assessing the clinical stage of AMD in patients or for determining
the stages of other types of eye disease) using single sensory
modality competing stimuli or mixed sensory modality competing
stimuli within the same test may be implemented by those skilled in
the art based on the specific examples in the experiments disclosed
and the general principles and methods of competition of stimuli as
disclosed herein.
[0668] It is further noted that the methods, systems and devices of
the present invention may be used to detect and assess retinal and
choroidal lesions which cause vision abnormalities in the eye.
While the devices methods and systems disclosed hereinabove and
illustrated in the drawings have been adapted for detecting and
assessing the presence and/or clinical stages of AMD, the devices
methods and systems disclosed may also be used or adapted for
detecting or assessing other types of vision abnormalities or eye
diseases. For example the following types of eye diseases or
retinal or choroidal pathologies may be detected or assessed or
diagnosed by suitable adaptation and/or modifications of the
methods devices and systems of the present invention, ocular
hystoplasmosis, myopia, central serous retinopathy, central serous
choroidopathy, glaucoma, diabetic retinopathy, media opacities
(such as, but not limited to, cataract), retinitis pigmentosa,
optic neuritis, epiretinal membrane, vascular abnormalities and/or
occlusions, choroidal dystrophies, retinal dystrophies, macular
hole, choroidal or retinal degeneration, lens abnormalities, and
the like.
[0669] It will be appreciated that the preferred embodiments
disclosed hereinabove and illustrated in the drawings are given by
way of example only and that many variations, permutations and
modifications of the present invention may be made which are within
the scope and spirit of the present invention.
* * * * *