U.S. patent application number 09/745529 was filed with the patent office on 2001-07-12 for ophthalmic apparatus.
This patent application is currently assigned to NIDEK CO., LTD.. Invention is credited to Takada, Yasutoshi.
Application Number | 20010007494 09/745529 |
Document ID | / |
Family ID | 18530553 |
Filed Date | 2001-07-12 |
United States Patent
Application |
20010007494 |
Kind Code |
A1 |
Takada, Yasutoshi |
July 12, 2001 |
Ophthalmic apparatus
Abstract
An opthalmic apparatus includes an illumination optical system
for illuminating an eye of a patient, the illumination optical
system including a plurality of LEDs which are illumination light
sources for emitting beams of light of wavelengths in different
regions and a composing optical system for composing optical paths
of the beams of light emitted from the LEDs, an observation optical
system for observing the patient's eye, and a light quantity
control section capable of controlling an illumination light
quantity of each of the LEDs to produce substantially white
illumination light.
Inventors: |
Takada, Yasutoshi;
(Gamagori-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
NIDEK CO., LTD.
|
Family ID: |
18530553 |
Appl. No.: |
09/745529 |
Filed: |
December 26, 2000 |
Current U.S.
Class: |
351/221 |
Current CPC
Class: |
A61F 9/08 20130101; A61B
3/0008 20130101; A61B 3/13 20130101; A61B 3/12 20130101 |
Class at
Publication: |
351/221 |
International
Class: |
A61B 003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 7, 2000 |
JP |
2000-1314 |
Claims
What is claimed is:
1. An ophthalmic apparatus including: an illumination optical
system for illuminating an eye of a patient, the illumination
optical system including a plurality of LEDs which are illumination
light sources for emitting beams of light of wavelengths in
different regions and a composing optical system for composing
optical paths of the beams of light emitted from the LEDs; an
observation optical system for observing the patient's eye; and a
light quantity control section capable of controlling an
illumination light quantity of each of the LEDs to produce
substantially white illumination light.
2. The ophthalmic apparatus according to claim 1 further including:
an irradiation optical system for irradiating a visible laser beam
for treatment to the patient's eye, and a protective filter for
preventing the treatment laser beam from entering an eye of an
observer, the protective filter being disposed insertably into and
removably from an observation optical path of the observation
optical system, wherein the light quantity control section changes
a ratio of the light emission quantities of the LEDs in association
with at least one of insertion and removal of the protective
filter.
3. The ophthalmic apparatus according to claim 2 further including
a sensor for detecting a presence or absence of the protective
filter in the observation optical path, wherein the light quantity
control section changes the ratio of the light emission quantities
of the LEDs based on a detection result by the sensor.
4. The ophthalmic apparatus according to claim 2, wherein the light
quantity control section changes the ratio of the light emission
quantities of the LEDs so that an observation image obtained in a
presence of the protective filter in the observation optical path
has a substantially same tone as an observation image obtained in
an absence of the protective filter in the observation optical
path.
5. The ophthalmic apparatus according to claim 2, wherein, when the
protective filter is inserted into the observation optical path,
the light quantity control section relatively increases the light
emission quantity of an LED for emitting light of a color
corresponding to a wavelength region to be cut by the protective
filter.
6. The ophthalmic apparatus according to claim 1, wherein the
plurality of LEDs include an LED for emitting red light, an LED for
emitting green light, and an LED for emitting blue light.
7. The ophthalmic apparatus according to claim 1 further including
a selection key for selectively causing the plurality of LEDS to
emit light, wherein the light quantity control section is capable
of controlling the light emission quantity of each of the LEDs
based on selection by means of the selection key.
8. The ophthalmic apparatus according to claim 1 further including
a light adjusting knob or a light adjusting key for changing the
light quantity of substantially white illumination light, wherein
the light quantity control section changes the light emission
quantity of each of the LEDs based on adjustment by means of the
light adjusting knob or key while the ratio of the light emission
quantities of the LEDs is kept unchanged.
9. An ophthalmic apparatus including; an illumination optical
system for illuminating an eye of a patient, the illumination
optical system including a plurality of LEDs which are illumination
light sources for emitting beams of substantially white light and a
composing optical system for composing optical paths of the beams
of light emitted from the LEDs; an observation optical system for
observing the patient's eye; and a light quantity control section
for controlling the light emission quantity of each of the
LEDs.
10. The ophthalmic apparatus according to claim 9 further
including: an irradiation optical system for irradiating a visible
laser beam for treatment to the patient's eye, and a protective
filter for preventing the treatment laser beam from entering an eye
of an observer, the protective filter being disposed insertably
into and removably from an observation optical path of the
observation optical system, wherein the light quantity control
section changes a ratio of the light emission quantities of the
LEDs in association with at least one of insertion and removal of
the protective filter.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an ophthalmic apparatus for
performing observation or treatment by illuminating an eye of a
patient.
[0003] 2. Description of Related Art
[0004] As an ophthalmic apparatus for observing a patient's eye,
there is known a slit lamp for projecting slit-shaped illumination
light on the patient's eye, thereby allowing observation through an
observation optical system, or a laser treatment apparatus
constructed by a combination of the slit lamp and a laser
irradiation device.
[0005] These ophthalmic apparatus each cause an illumination light
source provided inside of the apparatus to project illumination
light on the patient's eye to thereby performing observation and
treatment. A tungsten lamp, a halogen lamp or the like is generally
used for the illumination light source.
[0006] However, an illumination light source using a lamp is short
in service life. Thus, such illumination light source requires
frequent replacement, which is cumbersome and imposes burden on
operators or the like. In addition, the lamp has a large heat rate
during illumination, and may have a thermal effect on its
periphery. It is therefore required to pay attention to a material
or an installation position, etc. of the periphery of the
illumination light source during design.
[0007] The slip lamp is provided with a mechanism to insert/remove
a wavelength selection filter for enabling fluorescent observation
or the like into/from an illumination optical path. This may
increase complexity in configuration of the apparatus.
[0008] In many cases, a laser treatment apparatus for performing
photocoagulation or the like is provided with a protective filter
disposed in an observation optical path in order to protect an
operator's eye from a laser beam for treatment reflected from the
patient's eye or the like. However, in the case of observation
through a protective filter for cutting a visible treatment laser
beam, an observation image looks more colorful than that in the
case where no protective filter is provided, has strangeness, and
makes it difficult to ensure observation.
SUMMARY OF THE INVENTION
[0009] The present invention has been made in view of the above
mentioned technical problems. It is an object of the present
invention to provide an ophthalmic apparatus provided with an
illumination light source which is easy-to-handle and arranged in
simplified configuration.
[0010] Another object of the present invention is providing an
ophthalmic apparatus capable of facilitating observation even in
the presence of a protective filter during laser treatment.
[0011] In order to solve the foregoing problems, the present
invention is characterized by comprising the following constituent
elements.
[0012] According to a first aspect of the present invention, there
is provided an ophthalmic apparatus including: an illumination
optical system for illuminating an eye of a patient, the
illumination optical system including a plurality of LEDs which are
illumination light sources for emitting beams of light of
wavelengths in different regions and a composing optical system for
composing optical paths of the beams of light emitted from the
LEDs; an observation optical system for observing the patient's
eye; and a light quantity control section capable of controlling an
illumination light quantity of each of the LEDs to produce
substantially white illumination light.
[0013] According to another aspect of the present invention, there
is provided an ophthalmic apparatus including: an illumination
optical system for illuminating an eye of a patient, the
illumination optical system including a plurality of LEDs which are
illumination light sources for emitting beams of substantially
white light and a composing optical system for composing optical
paths of the beams of light emitted from the LEDS; an observation
optical system for observing the patient's eye; and a light
quantity control section for controlling the light emission
quantity of each of the LEDs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings, which are incorporated in and
constitute a part of this specification illustrate an embodiment of
the invention and, together with the description, serve to explain
the objects, advantages and principles of the invention.
[0015] In the drawings,
[0016] FIG. 1 is an external view showing a laser treatment
apparatus in an embodiment according to the present invention;
[0017] FIG. 2 is a schematic view showing an optical system of the
apparatus;
[0018] FIG. 3 is a block diagram schematically showing a control
system of the apparatus;
[0019] FIG. 4 is a view showing wavelength characteristics of each
LED;
[0020] FIG. 5 is a view showing wavelength transmission
characteristics of a protective filter; and
[0021] FIG. 6 is a block diagram schematically showing a mechanism
for selectively lighting LEDs.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] A detailed description of a preferred embodiment of an
ophthalmic apparatus embodying the present invention will now be
given referring to the accompanying drawings. The present
embodiment exemplifies a laser treatment apparatus as the
ophthalmic apparatus according to the present invention. FIG. 1 is
an external view showing a laser treatment apparatus for performing
photocoagulation treatment by irradiating a laser light beam for
treatment (hereinafter, merely referred to as a treatment beam) to
the periphery an affected part of a patient's eye. FIG. 2 is a
schematic view showing an opitical system of the apparatus.
[0023] Reference numeral 1 denotes a main body of the laser
treatment apparatus. Reference numeral 2 is a control board for
setting and inputting irradiation output conditions of the
treatment beam. Reference numeral 3 denotes a slit lamp delivery
comprising a laser irradiation optical system 30, an illumination
optical system 40, and an observation optical system 50. Reference
numeral 4 is a fiber cable for delivering the treatment beam or an
aiming laser light beam (hereinafter, merely referred to as an
aiming beam) from the main body 1 to the slit lamp delivery 3.
Reference numeral 5 is a foot switch for generating a trigger
signal to start Laser irradiation. Reference numeral 6 is a
joystick for moving the slit lamp delivery 3.
[0024] Reference numeral 7 denotes a switch for lighting LEDs
41a-41c that constitute an illumination light source incorporated
in the slit lamp delivery 3. Reference numeral 8 denotes a light
adjusting knob for adjusting an illumination light quantity.
Reference numeral 9 is a cable connecting between the slit lamp
delivery 3 and a control section 60 (see FIG. 3) on the side of the
main body 1. The cable 9 is used for transmitting and receiving a
command signal to insert/remove a protective filter 57 with respect
to an optical path of the observation optical system 50
(hereinafter, referred to as an observation optical path) or a
detection signal indicating the insertion or removal of the filter
57 (i.e. the presence or absence of the filter 57 in the
observation optical path). The cable 9 is also used to transmit
whether the toot switch 5 is active or inactive to the slit lamp
delivery 3.
[0025] Reference numeral 10 denotes a laser source for emitting a
treatment beam. In the present embodiment, as the laser source 10,
an Nd:YAG laser capable of oscillating a fundamental wave of 1064
nm is used to generate a green light of 532 nm (linearly polarized
light), which is double the fundamental wave. Reference numeral 11
is a beam splitter having the property of transmitting most part of
the treatment beam emitted from the laser source 10 while
reflecting a part of the beam. The part of the treatment beam
reflected by the beam splitter 11 enters an output sensor 13
through a diffusing plate 12 for detecting the output value of the
treatment beam.
[0026] Reference numeral 14 is a safety shutter. When the foot
switch 5 is depressed, issuing a command for laser irradiation
(i.e. generating a trigger signal), the safety shutter 14 is
removed from the optical path, thus enabling the passing of the
treatment beam. In case where an abnormality occurs, the safety
shutter 14 is inserted into the optical path to thereby intercept
the laser beam. The opening and closing of this shutter 14 is
detected by means of a shutter sensor 14a.
[0027] Reference numeral 15 denotes a laser light source for
emitting an aiming beam. In the present embodiment, there is used a
semiconductor laser source capable of emitting a red aiming beam of
630 nm. The aiming beam emitted from the light source 15 passes
through a collimator lens 16 and is made coaxial to the treatment
beam by means of a dichroic mirror 17.
[0028] Reference numeral 18 is a second safety shutter. The opening
and closing of this shutter 18 is detected by a shutter sensor 18a.
Reference numeral 19 denotes a focusing lens for focusing the laser
beams (the treatment beam and the aiming beam) to an incident end
face 4a to enter the fiber 4. The laser beams are delivered through
the fiber 4 to the irradiation optical system 30 of the slit lamp
delivery 3.
[0029] The irradiation optical system 30 comprises a collimator
lens 31, a variable magnification lens group 32, an objective lens
33, and a driving mirror 34. An operator can operate a manipulator
(not shown), whereby to change the reflection angle of the driving
mirror 34 to fine adjust a laser irradiation position.
[0030] Reference numeral 40 denotes an illumination optical system.
Reference numerals 41a, 41b, and 41c each denote an LED used as an
illumination light source. The LEDs 41a-41c emit beams of
illumination light in wavelength regions for red (R), green (t),
and blue (B), respectively, that are the primary colors of
light.
[0031] The wavelength characteristics of each of the LEDs 41a, 41b,
and 41c are shown in FIG. 4. The LED 41a emits illumination light
of the blue wavelength region of which a peak light emission
wavelength is close to 460 nm, and the blue illumination light is
allowed to pass through dichroic mirrors 80 and 81 disposed on an
optical axis L. The LED 41b emits illumination light of a green
wavelength region of which a peak light emission wavelength is
close to 520 nm. The green illumination light is reflected by the
dichroic mirror 80 to be composed with the blue illumination light.
Then, the resultant light is allowed to pass through the dichroic
mirror 81. The LED 41c emits illumination light of a red wavelength
region of which a peak light emission wavelength is close to 630
nm. The red illumination light is reflected by the dichroic mirror
81 to be composed with the beams of blue and green illumination
light.
[0032] In the present embodiment, although the dichroic mirrors 80
and 81 are used to make the beams of illumination light (red,
green, and blue light beams) coaxial to each other (composed with
each other), the present invention is not limited to such dichroic
mirror. A beam combining device such as half mirror, polarizing
plate, or prism may be used.
[0033] The beams of visible illumination light emitted from the
LEDs 41a-41c and made coaxial (composed with each other) on the
optical axis L are allowed to pass through a condenser lens 42. A
height and a width of the resultant light are determined by a
variable circular aperture plate 43 and a variable slit plate 44
respectively to be formed into a slit-shaped luminous flux. Then,
the slit-shaped illumination light is allowed to pass through a
projection lens 46 and then reflected by dividing mirrors 48a and
48b toward the patient's eye E. The light thus illuminates the eye
E through a contact lens 49. Reference numeral 47 is a correction
lens, and reference numeral 45 is a wavelength selection filter to
be inserted into or removed from the optical path of the
illumination optical system 40 (hereinafter, referred to as
illumination optical path).
[0034] An observation optical system 50 comprises: an objective
lens 51 shared between the left and right observation optical
paths; a variable magnification lens 52; an image forming lens 53;
an erect prism 54; a field diaphragm 55; eyepiece lenses 56; and
the protective filter 57; the elements 53-57 being disposed in the
left and right observation optical paths, respectively. FIG. 5 is a
view showing wavelength transmission characteristics of the filter
57. The filter 57 used in the present embodiment has the property
of cutting 99% or more of light of a narrow bandwidth wavelength
region (520 nm-540 nm), the center of which is 532 nm of the
treatment beam, while allowing most of light of the visible
wavelength region.
[0035] The filter 57 is arranged to be insertable into or removable
from the observation optical path by means of a movement mechanism
constructed of a motor or the like (not shown). The insertion and
removal of the filter 57 with respect to the observation optical
path is effected based on the presence or absence of the trigger
signal from the foot switch 5. The condition of the filter 57, or
the presence or absence of the filter 57 in the observation optical
path, is detected by means of a sensor 57a.
[0036] Operation of the apparatus constructed as above will be
described with reference to a block diagram schematically showing a
control system shown in FIG. 3.
[0037] An operator turns on the LEDs 41a-41c by means of the switch
7. At this time, the light quantity of each of the illumination
light beams emitted from the LEDs 41a-41c is controlled in advance
by a light quantity control section 61 so that white illumination
light is produced after three luminous fluxes (red, green, and
blue) have been composed. To be more specific, the light quantities
of the LEDs 41a, 41b, and 41c are each controlled so that the light
quantities have the following ratio; LED 41a: LED 41b: LED 41c
(B:G:R)=0.5:0.6:1.0.
[0038] As a result, the illumination light beams emitted from the
LEDs 41a-41c are changed into a substantially white illumination
light after they are composed; the white illumination light
illuminates the patient's eye E; and the operator can obtain an
observation image (observation visual field) in close to a natural
color. It in to be noted that the light quantity ratio is not
limited to the above, another ratio may be adopted if only the
color of the illumination light produced by composition is within a
region of white light.
[0039] Even when the light quantity of illumination light projected
to the patient's eye E is changed by using the light adjusting knob
8, the light quantity is increased or decreased by the light
quantity control section 61 without changing the ratio of the light
emission quantities of the LEDs 41a-41c. This makes it possible to
maintain the illumination light after composed in a substantially
white color.
[0040] Since the LED is used as the illumination light source in
the present embodiment, heating quantity can be reduced, thus
eliminating the need to consider a thermal effect caused by the
illumination light from the LED. Such each LED has its long service
life, and may not be frequently replaced.
[0041] The illumination light beams from the LEDs 41a, 41b, and 41c
are composed by the dichroic mirrors 80 and 81, whereby
substantially white illumination light is produced as described
above, which illuminates the patient's eye E through the
illumination optical system 40. The operator can observe through
the observation optical system 50 the fundus of the patient's eye E
illuminated by the white illumination light.
[0042] Next, the aiming laser source 15 is lit by a switch (not
shown) on the control board 2. Upon setting of the emission of the
aiming beam, the control section 60 causes the shutter 18 to be
removed from the optical path.
[0043] The operator operates the joystick 6 and a manipulator (not
shown) while observing the aiming beam irradiated to the eye
fundus, and performs alignment with respect to an affected part of
the eye fundus. The operator sets irradiation conditions such as
the irradiation power or irradiation time of the treatment beam by
using various switches on the control board 2. When the laser
irradiation is ready, a READY status is established such that the
irradiation of the treatment beam is enabled. Then, the operator
operates the manipulator (not shown) to make fine adjustment for
alignment with the affected part. After completion of the
alignment, the operator depresses the foot switch 5 to start the
laser irradiation. Upon receipt of the trigger signal from the foot
switch 5, the control section 60 generates a command signal to
insert the filter 57 into the observation optical path. The sensor
57a detects that the filter 57 is inserted into the observation
optical path and transmits the detection signal to the light
quantity control section 61.
[0044] Upon receipt of the detection signal from the sensor 57a,
the light quantity control section 61 changes the ratio of the
light quantities of the LEDs 41a-41c in synchronization with the
insertion of the filter 57 into the observation optical path. A
change quantity of this light quantity ratio is preset so that the
light densities of R, G, and B that pass through the filter 57 are
close to those obtained in the absence of the filter 57 in the
observation optical path.
[0045] The above change of the light quantity ratio by the light
quantity control section 61 is effected for the following
reason.
[0046] That is, when the reflection light from the patient's eye E
passes through the filter 57, light of wavelengths in a range of
520 nm to 540 nm is cut by the filter 57 in order to cut the
treatment beam. In association with this, the density of the green
light is reduced. In this case, the ratio of the light quantities
of the light beams passed through the filter 57 becomes the
following relation; B:G:R=0.8:0.3:1.0. Consequently, the entire
observation image obtained during observation through the filter 57
is more colorful (purplish) than that obtained in the absence of
the filter 57.
[0047] To compensate for the density of the green light cut by the
filter 57, the density of light of a green wavelength region which
is allowed to pass through the filter 57 is relatively
increased.
[0048] The ratio of respective light quantities of the LEDs 41a-41c
is changed, for example, by increasing the light quantity of LSD
41b, while decreasing those of the LEDs 41a and 41c, so that the
light quantity ratio of the light beams passed through the filter
57 is adjusted to the relation; B:G:R=0.5:0.6:1.0. In this case,
the ratio of respective actual light quantities of the LEDs shows
the following relation; LED 41a: LED 41b LED 41c (B:G:R)=
0.3:1.0:0.9. In this manner, the colored degree of an observation
image is lowered, and an observation image produced in the presence
of the filter 57 in the observation optical path can be given the
tone close to the observation image produced in the absence of the
filter 57 therein.
[0049] Relative control of the light quantity ratio of the LEDs
41a-41c may be experimentally determined so that the tones of the
observation images in the presence and the absence of the filter 57
are as identical to each other as possible.
[0050] When confirmed the insertion of the filter 57 into the
observation optical path through the sensor 57a (when received the
detection signal representative of the presence of the filter 57
from the sensor 57a), the control section 60 causes the shutter 14
to be removed from the optical path and the laser source 10 to emit
the treatment beam. The treatment beam is delivered through the
optical system in the main body 1, the fiber 4, and the irradiation
optical system 30, to irradiate the affected part of the patient's
eye E.
[0051] Even if the filter 57 is inserted during laser irradiation,
i.e., in the observation optical path, the observation image is
obtained in a color state close to a natural color which is
obtained during the observation in the absence of the filter 57.
Thus, the state of the affected part or treatment result can be
observed without any strangeness. Further, even when the filter 57
is placed in the observation optical path for a long time for
continuous laser irradiation, there is no need to remove the filter
57 in the middle of treatment because of a low visibility in order
to allow the operator to check the treatment state without the
filter 57. The light quantity control mentioned above is therefore
particularly effective for the continuous laser irradiation.
[0052] When the operator stops depressing the foot switch 5, no
trigger signal is generated therefrom. In response to no signal
from the foot switch 5, the control section 60 stops the laser
emission from the laser source 10 and removes the filter 57 from
the observation optical path. In association with the detection
signal from the sensor 57a that has detected the removal of the
filter 57, the light quantity control section 61 resets the light
quantity ratio of the LEDs 41a-41c to the original light quantity
ratio used before the insertion of the filter 57. In this manner,
even after the filter 57 is removed from the observation optical
path, there can be obtained an observation image with substantially
the same tone as that obtained before the insertion of the filter
57 into the observation optical path.
[0053] The present invention may be embodied in other specific
forms without departing from the essential characteristics
thereof.
[0054] For instance, in the above embodiment, the light quantity
ratio of the LEDs 4la-41c is changed in association with the
detection signal from the sensor 57a representing the
presence/absence of the filter 57 in the observation optical path.
Alternatively, the ratio may be changed in response to the trigger
signal from the foot switch 5.
[0055] The above embodiment has described an example of using three
types of LEDs for emitting beams of illumination light of
wavelengths in regions for R, G, and B. However, if those three
types of LEDs are insufficient to produce a substantially white
illumination light, the types of LEDs for emitting beams of
illumination light of wavelengths in different regions from the
above three regions may be further increased so that the
substantially white illumination light is easily obtained. In the
case where the illumination light quantity is insufficient, the
number of LEDs may be increased for each color.
[0056] Furthermore, although the present embodiment describes an
example of a laser treatment apparatus, the present invention is,
of course, applicable to only a slit lamp. In this case, there is
conveniently provided selection keys 70a, 70b, and 70c for
selectively lighting the LEDs 41a, 41b, and 41c for B, G, and R
light or individually adjusting the light quantity of each of the
41a-41c (see FIG. 6). For example, in the fluorescent observation
using fluorescein eyewash, the LED 41a is lit so that the patient's
eye E is illuminated by blue illumination light capable of exciting
fluorescein.
[0057] In the observation of blood vessels of conjunctiva or the
like, the LED 41b for emitting green illumination light is lit
without illumination by red illumination light, thereby
facilitating the observation. This makes it also possible to
eliminate a filter mechanism for selecting wavelengths from the
illumination optical system 40. In such a case, an LED for emitting
light of wavelengths required for the fluorescence observation or
the like may be provided in advance as an LED for an illumination
light source.
[0058] Alternatively, the light quantity of red illumination light
may be reduced or the light quantity of green illumination light or
blue illumination light may be increased in order to finely adjust
the illumination light to an easy-to-observe color according to the
color of an observation site.
[0059] The lighting of the LEDs 41a-41c or the light quantity
control is effected by the light quantity control section 61
connected to the selection keys 70a-70c. In the case where the
entire illumination light quantity is controlled without changing
the light quantity ratio of the colors, the knob 8 is used.
Alternatively, an LED for emitting illumination light of
wavelengths according to types of the fluorescence observation or
the like may be provided separately from the LED for an
illumination light source.
[0060] Furthermore, even if only one type of a white-emitting LED
is used without use of three types (R, G, and B) of LEDs, the use
of such white-emitting LED is very effective in heat generation and
service life in comparison with a conventional halogen lamp or
tungsten lamp.
[0061] As has been described above, according to the present
invention, the apparatus with an illumination light source which is
easy-to-handle and a simplified configuration can be achieved.
Furthermore, in the laser treatment, the affected part of the
patient's eye can be easily observed even in the presence of the
protective filter in the optical path of the observation optical
system.
* * * * *