U.S. patent application number 15/669727 was filed with the patent office on 2017-11-16 for customized multifocal ophthalmic lens.
The applicant listed for this patent is AMO Groningen B.V.. Invention is credited to Patricia Ann Piers, Marrie H. Van Der Mooren, Hendrik A. Weeber.
Application Number | 20170325937 15/669727 |
Document ID | / |
Family ID | 43031162 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170325937 |
Kind Code |
A1 |
Weeber; Hendrik A. ; et
al. |
November 16, 2017 |
CUSTOMIZED MULTIFOCAL OPHTHALMIC LENS
Abstract
System and method for customizing multifocal ophthalmic lenses,
such as an intraocular lens (IOL) or the like, that may be tailored
for an individual patient or group of patients beyond the selection
of a particular IOL power. One or more eye factors of the patient
are determined, a set of different multifocal intraocular lenses
having a similar base power are determined based on the eye
factors, and a multifocal intraocular lens is selected for the
patient from the set based on the eye factors.
Inventors: |
Weeber; Hendrik A.;
(Groningen, NL) ; Piers; Patricia Ann; (Groningen,
NL) ; Van Der Mooren; Marrie H.; (Engelbert,
NL) |
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Applicant: |
Name |
City |
State |
Country |
Type |
AMO Groningen B.V. |
Groningen |
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NL |
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Family ID: |
43031162 |
Appl. No.: |
15/669727 |
Filed: |
August 4, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12815157 |
Jun 14, 2010 |
9724190 |
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15669727 |
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PCT/US2008/086827 |
Dec 15, 2008 |
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12815157 |
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61007809 |
Dec 13, 2007 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29D 11/00038 20130101;
G02C 7/041 20130101; G06Q 50/22 20130101; A61F 2240/002 20130101;
A61F 2/1618 20130101 |
International
Class: |
A61F 2/16 20060101
A61F002/16; G02C 7/04 20060101 G02C007/04; B29D 11/00 20060101
B29D011/00; G06Q 50/22 20120101 G06Q050/22 |
Claims
1. A system (50) for producing a custom intraocular lens for a
patient, the system comprising: a memory (52) configured to store a
first database of lifestyle parameters, a second database of eye
factors, and a third database of multifocal intraocular lenses; a
processor (56) coupled to the memory and configured to: determine
an add power based on the first database and the second database;
and select the custom intraocular lens from the third database
based on the add power.
2. The system of claim 1, wherein the processor is further
configured to: apply a predetermined weighting to the lifestyle
parameters of the first database and the eye factors of the second
database to produce a first weighted database of lifestyle
parameters and a second weighted database of eye factors; and
determine the add power based on the first weighted database and
the second weighted database.
3. The system of claim 1, wherein at least some of the multifocal
intraocular lenses have a first intraocular lens power, and wherein
at least some of the multifocal intraocular lenses have different
optical characteristics, and wherein the custom intraocular lens is
configured to mitigate a presbyopia of the particular patient.
4. The system of claim 1, wherein the first database comprises a
preferred reading distance of the patient.
5. The system of claim 4, wherein the second database comprises an
axial length of an eye, and wherein the processor is further
configured to determine the add power based on the preferred
reading distance and the axial length of the eye.
6. The system of claim 1, wherein the second database comprises one
or more eye factors selected from a group consisting of a corneal
shape of an eye, a pupil diameter of an eye for a predetermined
viewing condition, a set of pupil diameters of an eye under a set
of predetermined viewing conditions, an axial length of an eye, a
keratometry factor, and a corneal radius of curvature factor.
7. The system of claim 1, wherein the processor is further
configured to select the custom intraocular lens from the third
database based on the add power and a treatment to an eye, the
treatment subsequent to an insertion of the custom intraocular lens
into the eye.
8. The system of claim 7, wherein the custom intraocular lens has
one or more characteristics, and wherein the treatment comprises an
adjustment to at least one of the one or more characteristics of
the custom intraocular lens.
9. The system of claim 7, wherein the eye with the custom
intraocular lens has a refraction, and wherein the treatment
comprises an adjustment to the refraction.
10. The system of claim 7, wherein the treatment comprises a laser
assisted refractive ophthalmic surgery.
11. A system (50) for producing a custom multifocal intraocular
lens having a diffractive surface with one or more echelettes, the
system comprising: a memory (52) configured to store a first
database of lifestyle parameters and a second database of eye
factors; a processor (58) coupled to the memory and configured to:
determine at least one characteristic of the one or more echelettes
based on the first database and the second database; and select a
diffractive multifocal intraocular lens based on the at least one
characteristic.
12. The system of claim 11, wherein the at least one characteristic
comprises one or more characteristics selected from a group
consisting of one or more heights of the one or more echelettes,
one or more diameters of the one or more echelettes, and one or
more profile shapes of the one or more echelettes.
13. The system of claim 11, wherein the second database comprises
one or more eye factors selected from a group consisting of a
corneal shape of an eye, a pupil diameter of the eye for a
predetermined viewing condition, an axial length of the eye, a
keratometry factor, and a corneal radius of curvature factor.
14. The system of claim 11, wherein the first database comprises a
preferred reading distance, wherein the second database comprises
an axial length of an eye, and wherein the processor is further
configured to determine the at least one characteristic in response
to the preferred reading distance and the axial length of the
eye.
15. The system of claim 11, wherein the processor is further
configured to select the diffractive multifocal intraocular lens
based on the at least one characteristic and a treatment to an eye,
the treatment subsequent to an insertion of the diffractive
multifocal intraocular lens into the eye.
16. The system of claim 15, wherein the diffractive multifocal
intraocular lens has one or more characteristics, and wherein the
treatment comprises an adjustment to at least one of the one or
more characteristics of the diffractive multifocal intraocular
lens.
17. The system of claim 15, wherein the eye with the diffractive
multifocal intraocular lens has a refraction, and wherein the
treatment comprises an adjustment to the refraction.
18. The system of claim 15, wherein the treatment comprises a laser
assisted refractive ophthalmic surgery.
19. A method of producing a multifocal intraocular lens for a
patient, the method comprising the steps of: determining one or
more eye factors of the patient; determining a set of different
multifocal intraocular lenses based on the one or more eye factors
of the patient, the set of multifocal intraocular lenses having a
similar base power; and selecting the multifocal intraocular lens
for the patient from the set of multifocal intraocular lenses based
on the one or more eye factors of the patient.
20. The method of claim 19, wherein at least some multifocal
intraocular lenses of the set of multifocal intraocular lenses have
central portions with associated sizes and add powers, and wherein
the step of selecting comprises selecting a first multifocal
intraocular lens from the set of multifocal intraocular lenses, the
first multifocal intraocular lens has a central portion and an add
power both based on the one or more eye factors of the patient.
21. The method of claim 19, wherein the selecting step comprises
selecting a diffractive multifocal intraocular lens for the patient
from the set of multifocal intraocular lenses based on the one or
more eye factors of the patient.
22. The method of claim 19, further comprising determining an add
power of the multifocal intraocular lens for the patient based on
one or more lifestyle parameters of the patient and the one or more
eye factors of the patient, and wherein the selecting step
comprises selecting the multifocal intraocular lens for the patient
based on the add power.
23. The method of claim 22, wherein the one or more eye factors
comprise an axial length of the eye, and wherein the step of
determining an add power comprises determining the add power based
on one or more of eye factors selected from a group consisting of a
corneal shape of the eye, a pupil diameter of the eye for a
predetermined viewing condition, a keratometry factor, a corneal
radius of curvature factor, a preferred reading distance and the
axial length of the eye.
24. The method of claim 19, wherein the multifocal intraocular lens
for the patient has a diffractive surface with one or more
echelettes, wherein the method further comprises determining at
least one characteristic of one or more echelettes based on a set
of lifestyle parameters of the patient and an eye factor of the
patient, and wherein the selecting step comprises selecting the
diffractive multifocal intraocular lens from the set of multifocal
intraocular lenses based on the at least one characteristic of the
one or more echelettes.
25. The method of claim 24, wherein the at least one characteristic
comprises one or more characteristics selected from a group
consisting of one or more heights of the one or more echelettes,
one or more diameters of the one or more echelettes, and one or
more profile shapes of the one or more echelettes.
26. The method of claim 19, further comprising determining at least
one patient lifestyle parameter of the patient, and wherein the
selecting step comprises selecting one or more multifocal lens
parameters for the multifocal intraocular lens based on the at
least one lifestyle parameter and the one or more eye factors.
27. The method of claim 26, wherein the one or more multifocal lens
parameters comprises one or more parameters selected from a group
consisting of an add power amount, a depth of focus characteristic,
an aberration amount selected to at least partially correct for an
aberration of the cornea of the eye, a spectral transmission
characteristic, and a pupil dependent add power function.
28. The method of claim 26, wherein the one or more eye factors
comprises one or more factors selected from a group consisting of a
patient age, a corneal shape, a cataract grade, an estimated
postoperative pupil diameter of the eye for a predetermined viewing
condition, and a pre-existing intraocular lens.
29. The method of claim 26, wherein the at least one lifestyle
parameter comprises one or more parameters selected from a group
consisting of an amount of outdoor activity, an amount of reading
time, an amount of computer time, and a work environment.
30. The method of claim 19, wherein the selecting step further
comprises selecting the multifocal intraocular lens based on the
one or more eye factors and a treatment to an eye subsequent to an
insertion of the multifocal intraocular lens into the eye.
31. The method of claim 19, wherein the multifocal intraocular lens
has one or more characteristics, and wherein the selecting step
further comprises selecting multifocal intraocular lens based on
the one or more eye factors and a treatment to an eye subsequent to
an insertion of the multifocal intraocular lens into the eye, the
treatment comprising an adjustment to at least one of the one or
more characteristics of the multifocal intraocular lens.
32. The method of claim 19, wherein the eye with the multifocal
intraocular lens has a refraction, and wherein the selecting step
further comprises selecting the multifocal intraocular lens based
on the one or more eye factors and a treatment to an eye subsequent
to an insertion of the multifocal intraocular lens into the eye,
the treatment comprising an adjustment to the refraction.
33. The method of claim 19, wherein the selecting step further
comprises selecting the multifocal intraocular lens based on the
one or more eye factors and a treatment to an eye subsequent to an
insertion of the multifocal intraocular lens into the eye, the
treatment comprising a laser assisted refractive ophthalmic
surgery.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/007,809, filed Dec. 13, 2007 and PCT Application
No. PCT/US08/86827, filed Dec. 15, 2008.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] This invention generally relates to optical correction, and
in exemplary embodiments provides methods, devices, and systems for
mitigating or treating defects of the eye. Among the exemplary
embodiments, the invention may provide multifocal intraocular
lenses.
Background
[0003] Presbyopia is a condition that affects the accommodation
properties of the eye. As objects move closer to a young, properly
functioning eye, the effects of ciliary muscle contraction and
zonular relaxation allow the lens of the eye to become rounder or
more convex, and thus increase the optical power and ability of the
eye to focus at near distances. Accommodation can allow the eye to
focus and refocus between near and far objects.
[0004] Presbyopia typically develops as a person ages, and is
associated with a natural progressive loss of accommodation. A
presbyopic eye often loses the ability to rapidly and easily
refocus on objects at varying distances. The ability to focus on
objects at near distances may also diminish with the presbyopic
eye. Although this condition progresses over the lifetime of an
individual, the effects of presbyopia usually become noticeable
after the age of 45 years. By the age of 65 years, the crystalline
lens has often lost almost all elastic properties and has only a
limited ability to change shape, or residual accommodation.
Residual accommodation refers to the amount of accommodation that
remains in the eye. A lower degree of residual accommodation
contributes to more severe presbyopia, whereas a higher amount of
residual accommodation correlates with less severe presbyopia.
[0005] Along with reductions in accommodation of the eye, age may
also induce clouding of the lens due to the formation of cataracts.
Cataracts may form in the hard central nucleus of the lens, in the
softer peripheral cortical portion of the lens, or at the back of
the lens. Cataracts can be treated by the replacement of the cloudy
natural lens with an artificial lens. Phacoemulsification systems
often use ultrasound energy to fragment the natural lens and
aspirate the lens material from the eye. An artificial lens
replaces the natural lens in the eye, with the artificial lens
often being referred to as an intraocular lens (IOL).
[0006] After replacement of the natural lens with an intraocular
lens, patients may have little or no ability to adjust the optical
power associated with the optical tissues of the eye so as to
maintain visual quality when changing viewing distance (for
example, between viewing a far object while driving and viewing a
near object while reading small print). Fortunately, a variety of
technologies have been developed that enhance the ability of IOLs
to facilitate viewing objects at different distances. Multifocal
IOLs may, for example, rely on a diffractive optical surface to
direct portions of the light energy toward differing focal
distances, thereby allowing the patient to see both near and far
objects.
[0007] While generally successful at mitigating presbyopia, as with
all successes, still more improvements would be desirable. With
existing multifocal IOLs, the performance and patient satisfaction
may depend on several aspects related to the individual patient. As
a result, not all patients are satisfied with multifocal IOLs after
implantation for a variety of reasons.
[0008] In light of the above, it would be desirable to provide
improved IOLs for cataract patients and others. IOL lens design may
include a compromise among various design objectives. It would be
particularly beneficial if these improved IOLs could take advantage
of the capabilities of diffractive multifocal optics, and would
enhance patient satisfaction by having optical attributes that are
more tailored to the needs and desires of the patient.
SUMMARY OF THE INVENTION
[0009] The present invention generally provides improved optical
devices, systems, and methods, with exemplary embodiments providing
improved ophthalmic lenses. Customized multifocal ophthalmic
lenses, such as intraocular lenses (IOLs) and the like, may be
tailored or selected for an individual patient or group of
patients, rather than limiting the selection of the multifocal
ophthalmic lens to a particular IOL power (e.g., a
one-size-fits-all multifocal attempt at mitigation of presbyopia
for a wide variety of patients using a single IOL structure).
[0010] In one embodiment, a system for producing a custom
intraocular lens for a patient is provided. The system includes a
memory and a processor coupled to the memory. The memory is
configured to store a first database of lifestyle parameters, a
second database of eye factors, and a third database of multifocal
intraocular lenses. The processor is configured to determine an add
power based on the first database and the second database and
select the custom intraocular lens from the third database based on
the add power.
[0011] In another embodiment, a system is provided for producing a
custom multifocal intraocular lens having a diffractive surface
with one or more echelettes. The system includes a memory and a
processor coupled to the memory. The memory is configured to store
a first database of lifestyle parameters and a second database of
eye factors. The processor is configured to determine at least one
characteristic of the one or more echelettes based on the first
database and the second database and select a diffractive
multifocal intraocular lens based on the at least one
characteristic.
[0012] In another embodiment, a method of producing a multifocal
intraocular lens for a patient is provided including determining
one or more eye factors of the patient, determining a set of
different multifocal intraocular lenses based on the one or more
eye factors of the patient, and selecting the multifocal
intraocular lens for the patient from the set of multifocal
intraocular lenses based on the one or more eye factors of the
patient. The multifocal intraocular lenses of the set of have a
similar base power.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the drawings, wherein like reference numerals refer to
similar components:
[0014] FIG. 1 schematically illustrates an exemplary embodiment of
an intraocular lens incorporating aspects of the present
invention;
[0015] FIGS. 2-3 graphically illustrate optical performance, at
differing viewing distances, of multifocal diffractive intraocular
lenses having differing characteristics that may be suitable for
differing patients; and
[0016] FIG. 4 is a block diagram of an exemplary embodiment of a
system for customizing a multifocal lens.
DETAILED DESCRIPTION
[0017] The present invention generally provides improved ophthalmic
devices, systems, and methods. In exemplary embodiments, the
invention provides multifocal ophthalmic lenses (e.g., intraocular
lenses (IOLs) and the like) that employ refractive and/or
diffractive techniques, and that are customized for a particular
patient or patient population subgroup. Rather than being limited
to selection of a particular IOL power (which typically represents
a one-size-fits-all multifocal attempt at presbyopia mitigation for
a wide variety of patients using a single IOL structure), the
multifocal lens design is tailored or selected for an individual
patient or group of patients. For example, a multifocal intraocular
lens may be selected for the patient from among a set of
appropriate multifocal intraocular lenses based on one or more
patient parameters. As part of determining the appropriate
multifocal intraocular lenses for the set, one or more IOL
parameters/characteristics may be selected for emphasis or
weighting based on the patient parameter(s).
[0018] Some examples of patient parameters that may be considered
during selection, design, and/or fabrication of the custom
multifocal IOLs described herein include, but are not necessarily
limited to: estimated post-operative pupil size or sizes,
optionally under different viewing conditions including differing
lighting conditions (e.g., photopic, mesopic, or the like) and/or
differing viewing distances (e.g., near, far, or the like); age;
cataract grade; lifestyle assessment of the patient's vision needs
(such as based on a questionnaire, physician assessment, or the
like); shape of the cornea; length of the eye; anterior chamber
depth; historic refraction; medical status of the retina; any
combinations thereof; and the like.
[0019] Some IOL parameters that may be changed (or that may differ
among selectable alternative IOLs) or emphasized for different
patients include, but are not necessarily limited to: aberration
correction; add power(s) for far, near, and/or intermediate focus;
depth of focus of one or more focal points; intermediate vision;
spectral light transmission characteristics (e.g., violet, blue,
ultraviolet (UV) blockers, or the like); pupil dependent
characteristics (such as a central zone size, one or more of the
foregoing parameters as based on the pupil, or the like); and/or
other parameters.
[0020] A variety of multifocal intraocular lenses employing
refractive and/or diffractive techniques can be customized for a
particular patient or patient population subgroup and/or utilized
for selective population of a group or database of lenses
particularly suited for the patient or patient population subgroup.
An exemplary customized intraocular lens for a particular patient
may, for example, comprise a pupil-dependent bifocal diffractive
intraocular lens 10, as schematically illustrated in FIG. 1. The
lens 10 has a central portion 11 that includes a bifocal
diffractive structure 12 producing a 50:50 split of the incoming
light energy, with about an even distribution between the light
energy being directed to a first focal length and the light energy
being directed to a different focal length. Examples of diffractive
IOL structures are described, for example, in U.S. Pat. No.
5,144,483, and in U.S. Pat. No. 4,881,804, and examples of
refractive multifocal intraocular lenses are described in U.S. Pat.
Nos. 6,527,389; 5,225,858; and 6,557,998. Each of these references
is incorporated herein by reference, and some embodiments may
employ one or more structures similar to (or derived from) those
described by U.S. Pat. Nos. 4,881,804; 5,144,483; 6,527,389;
5,225,858; and 6,557,998. Other multifocal intraocular lenses
having refractive and/or diffractive elements may also be used for
customization or selection to populate a desired group of lenses
(e.g., meeting predetermined criteria for the particular
patient).
[0021] A peripheral portion 14 of the lens 10 may include a
monofocal structure that directs substantially all of the light
incident thereon to a single focal length. In one embodiment, the
differing focal lengths of the central portion 12 include a near
focus and a far focus, and the monofocal peripheral portion 14
directs light to the far focus. The diameter of the central portion
12 is in a range from about 1 mm to about 6 mm.
[0022] As the eye adjusts to different viewing conditions
(including both different levels of lighting and different viewing
distances), the pupil of the eye often varies in size. Different
patients have different pupil sizes. Additionally, the constriction
or change in pupil size of patients typically varies, so that two
patients that have the same pupil size when viewing the same
distant objects under low light conditions may have differing pupil
sizes when viewing the same near objects under bright light.
[0023] In an exemplary embodiment, the central portion 12 has a
size, such as a diameter 16, that is tuned to maximize the
performance of the lens 10 for an individual patient or group of
patients based at least in part on the patient pupil size. A lens
having a smaller central portion may be selected for patients
having smaller pupils, and a lens having a larger central portion
may be selected for patients having larger pupils.
[0024] In the exemplary embodiment of the lens 10, a specific lens
design may be chosen based on estimated post-operative pupil sizes.
Pupil sizes for the patient post-procedure (such as IOL insertion
and/or cataract removal) can be estimated based on preoperative
pupil sizes, patient age, the grade of cataract, the type of
surgical procedure that is planned, and other factors. Empirical
studies in which measurements of pupils are taken before and after
surgery for patients of different ages, grade of cataracts, and the
like, may be employed. Alternative embodiments may employ lens
types that can be adjusted post-operatively, such as structures
analogous to or derived from a Calhoun lens. When using such
structures, the post-operative pupil size can be measured and the
lens adjusted accordingly.
[0025] Alternative embodiments may be designed specifically to
allow or enhance postoperative ophthalmic treatments, such as laser
assisted refractive surgery, or to effect a desired optical outcome
in combination with additional ophthalmic lenses (e.g., eyeglasses,
contact lenses, intracorneal implants or inserts, and the like).
For example, laser assisted refractive surgery may be used to
fine-tune the refraction or to extend the depth of focus.
Combinations with additional ophthalmic lenses may comprise the use
of corneal inlays, contact lenses, or spectacles, in order to
fine-tune the optical characteristics, or to alter the image
magnification on the retina.
[0026] Regarding the interaction between pupil sizes under
different viewing conditions and the size of the central portion so
as to mitigate presbyopia, analogous approaches for presbyopia
correction using patient data are described in U.S. Pat.
Publication No. 2004/0169820 in the name Dai et al., the full
disclosure of which is incorporated herein by reference. For
example, a prescription may be established that mitigates or treats
presbyopia for the particular patient, and the shape of the
multifocal intraocular lens may be designed or selected to
correspond to the optical shape associated with this prescription.
Some embodiments of the lens 10 may have optical or other
characteristics as described in U.S. Pat. Publication No.
2004/0169820, although other embodiments omit the same. For
example, some embodiments of the lens 10 may have optical or other
characteristics associated with one or more of the ablation shapes
for mitigating presbyopia described in U.S. Pat. Publication No.
2004/0169820.
[0027] Note that the lens 10 need not necessarily be limited to a
bifocal lens embodiment. Other embodiments that may employ aspects
of the present invention include trifocal lenses, aspheric lenses,
and the like. For example, aspheric IOLs are described in U.S. Pat.
No. 6,609,793 in the name of Norrby et al., in U.S. Pat.
Publication No. 2004/0156014 in the name of Piers et al., and in
other references. Both of the above-referenced applications are
incorporated herein by reference. Related approaches for mitigation
and/or correction of presbyopia using patient data may also employ
multifocal apodization, such as described in U.S. Pat. No.
5,699,142, in the name of Lee et al. (also incorporated herein by
reference), as well as other apodized multifocal approaches.
[0028] Techniques and approaches developed for contact lenses may
also be employed in some aspects of the present invention. For
example, the design of the contact lens characteristics described
in U.S. Pat. Publication No. 2004/0085515, the disclosure of which
is incorporated herein by reference, may be employed to customize
the optical characteristics of the multifocal intraocular lens for
the patient.
[0029] Some embodiments may benefit by using lower add power in the
central portion 11. Lowering add power can result in an increased
(e.g., farther) reading distance and improved viewing of
intermediately positioned objects. The modulation transfer function
(MTF) may be somewhat lower, and less halo and scatter can occur
when the add power is limited to less than 3 D, the add power often
being less than 2.5 D and optionally being 2 D or less.
[0030] Referring to FIGS. 2 and 3, optical performance, at
differing viewing distances, of different multifocal diffractive
intraocular lenses are graphically illustrated. Each of these
intraocular lenses have characteristics that may be suitable for
different patients. FIG. 2 is a through-focus plot of modulation
transfer functions (MTFs) 20, 22, 24, 26 at 50 line pairs per mm
(or, equivalently, cycles per mm or c/mm) for different multifocal
diffractive IOLs at a first pupil size (e.g., about 3 mm). This
pupil size may correspond with a normal viewing condition. A first
MTF 20 is associated with a diffractive multifocal IOL without add
power. A second MTF 22 is associated with a diffractive multifocal
IOL with about 3.5 D of add power. A third MTF 24 is associated
with a diffractive multifocal IOL with about 2 D of add power. A
fourth MTF 26 is associated with a diffractive multifocal IOL with
about 1 D of add power. The fourth MTF 26 associated (with the
relatively lower add power) indicates a region of extended depth of
focus, in comparison with the other MTFs 20, 22, 24.
[0031] FIG. 3 is a through-focus plot of modulation transfer
functions (MTFs) 30, 32, 34, 36 for different multifocal
diffractive IOLs at a second pupil size (e.g., about 5 mm). In
contrast with the first pupil size (associated with the MTFs 20,
22, 24, 26 shown in FIG. 2), this pupil size may correspond with a
lower lighting viewing condition compared with the normal viewing
condition. A first MTF 30 is associated with a diffractive
multifocal IOL without add power. A second MTF 32 is associated
with a diffractive multifocal IOL with about 3.5 D of add power. A
third MTF 34 is associated with a diffractive multifocal IOL with
about 2 D of add power. A fourth MTF 36 is associated with a
diffractive multifocal IOL with about 1 D of add power. The fourth
MTF 36 (with the relatively lower add power) indicates a region of
extended depth of focus, in comparison with the other MTFs 30, 32,
34, under lower lighting viewing conditions.
[0032] As best shown in FIGS. 2 and 3, each of the corresponding
multifocal diffractive IOLs have different properties corresponding
with different optical performances. A variety of structural
elements may be used to produce the desired multifocal diffractive
IOL. For example, a diffractive pattern with a relatively low add
power may be imposed on one shape to define the overall form of a
posterior surface of the optic. The preceding embodiments are
merely for illustrative purposes, and should not be construed as
limiting in any way. The parameters of the multifocal diffractive
IOL may also be adjusted to suit a particular set of design
objectives or to reflect a particular set of measurements for a
particular set of eyes or an individual eye. For example, the
factors for the eye may be selected or weighted for priority
consideration in the IOL design based on statistical averages for a
particular population. In addition, the design of the diffractive
element may be adjusted to provide a predetermined visual response
within the eye of a subject or patient.
[0033] Many of the methods, devices, and systems described herein
will take advantage of an optical characteristic of the eye or eye
factor. Exemplary eye factors include one or more measurements of
the eye (e.g., a pupil diameter at a predetermined viewing
condition), a set of pupil diameters each associated with a
different predetermined viewing condition, a corneal shape of the
anterior corneal surface (e.g., measured by corneal topography
and/or by a keratometer), a corneal shape of the posterior corneal
surface (e.g., measured by Scheimpflug photography using a
Pentacam.TM. measurement system or the like), a length of the eye
(e.g., the axial length of the eye as measured using A-scan
biometry, Laser Interference Biometry such as with the
IOLMaster.TM., or the like), an anterior chamber depth, and/or the
patient's historic refraction. A wide variety of measurement
devices may be used to obtain these or other optical
characteristics of the patient's eye useful for the presbyopia
mitigation described herein.
[0034] Effective presbyopia mitigation for a particular patient may
also benefit from data regarding the lifestyle of that patient or
lifestyle parameters. Such patient lifestyle parameters may be
identified by measurements, observations, questionnaires from the
patient or others in contact with or having knowledge about the
patient, and the like. The patient lifestyle parameters may be
stored in a memory having an updateable database. Exemplary patient
lifestyle parameters may include or indicate a preferred reading
distance, a preference for reading vision or intermediate vision,
an occupation, hobbies, an amount and/or type of outdoor activity,
an amount of reading time, an amount of computer time, a work
environment, and/or the like. Additionally, one or more of the
patient lifestyle parameters may be selected for emphasis (e.g.,
using a weighting format) when customizing the lens characteristics
to the patient.
[0035] Based on the eye factors and lifestyle parameters, one or
more suitable refractive prescription lenses may be selected and/or
designed for a particular presbyopia patient so as to mitigate the
disadvantages of presbyopia for that patient. In one embodiment,
the prescriptive lens includes a diffractive multifocal lens, and a
variety of lens parameters may be determined and/or selected. For
example, the diffractive multifocal lens can have one or more
echelettes. The term echelette is referred to herein as a generally
V-shaped groove formed on the lens surface. Examples of lens
parameters include a lens profile height, the diameters associated
with the echelettes, the echelette profile shape, and the like.
Additionally, the design may, for example, be pupil dependent, and
the profile height may vary for each echelette. Each echelette may
also have a different diameter. In addition, with pupil dependent
designs or other designs emphasizing specific patient desires (e.g.
for a patient highly valuing an extended depth of focus), one or
more of the echelette diameters may be different from those of more
conventional diameters and designs. Furthermore, with pupil
dependent designs, the profile shape can be selected to be
different for each echelette.
[0036] Other lens parameters may also be determined in response to
the eye factors or lifestyle parameters, including but not
necessarily limited to spectral transmission characteristics,
spherical aberration correction, induced negative spherical
aberration for mitigation of presbyopia (e.g., U.S. Pat. No.
7,261,412, the disclosure of which is incorporated herein by
reference), cylinder (such as a toric multifocal lens), and/or
corneal coma correcting optical elements. Cylinder correction and
coma correction may also be considered as aberration corrections.
Still further variations and alternative lens characteristics and
parameters may be included, including biconvex shapes, a
diffractive profile(s) on anterior and/or posterior lens surface,
etc.
[0037] The present invention also provides systems for customizing
or optimizing a multifocal IOL for a patient to mitigate presbyopia
or other vision conditions of the patient. For example, as shown in
FIG. 4, a system 50 can be used for selecting or designing a
multifocal IOL. The system 50 includes an input 54 (e.g., a user
interface such as a display with an input device (e.g.,
touch-sensitive screen, mouse, touchpad, keyboard, or the like)
that accepts one or more patient lifestyle parameters and one or
more eye factors associated with a patient, a memory 52 coupled to
the input 54 that stores the patient lifestyle parameters and eye
factors, and a processor 56 coupled to the input 54 and the memory
52. The memory 52 may additionally store a database of multifocal
IOLs for the patient, which can be populated via the input 54 or by
a candidate selection process performed by the processor 56.
[0038] The processor 56 includes computer hardware and/or software,
often including one or more programmable processor units running
machine readable program instructions or code for implementing some
or all of one or more of the methods described herein. In one
embodiment, the code is embodied in a tangible media such as a
memory (optionally a read only memory, a random access memory, a
non-volatile memory, or the like) and/or a recording media (such as
a floppy disk, a hard drive, a CD, a DVD, a memory stick, or the
like). The code and/or associated data and signals may also be
transmitted to or from the processor 56 via a network connection
(such as a wireless network, an Ethernet, an internet, an intranet,
or the like), and some or all of the code may also be transmitted
between components of the system 50 and within the processor 56 via
one or more bus, and appropriate standard or proprietary
communications cards, connectors, cables, and the like can be
included in the processor 56.
[0039] The processor 56 is preferably configured to perform the
calculations and signal transmission steps described herein at
least in part by programming the processor 56 with the software
code, which may be written as a single program, a series of
separate subroutines or related programs, or the like. The
processor 56 may include standard or proprietary digital and/or
analog signal processing hardware, software, and/or firmware, and
has sufficient processing power to perform the calculations
described herein during treatment of the patient. The processor 56
optionally includes a personal computer, a notebook computer, a
tablet computer, a proprietary processing unit, or a combination
thereof. Standard or proprietary input devices (such as a mouse,
keyboard, touchscreen, joystick, etc.) and output devices (such as
a printer, speakers, display, etc.) associated with modern computer
systems may also be included with the system 50, and additional
processors having a plurality of processing units (or even separate
computers) may be employed in a wide range of centralized or
distributed data processing architectures.
[0040] In this embodiment, the processor 56 determines or selects a
particular multifocal IOL based on the patient lifestyle parameters
and one or more eye factors. For example, the processor 56 can
determine at least one characteristic of the echelettes associated
with a candidate multifocal IOL based on the patient lifestyle
parameters and the eye factors. A diffractive multifocal IOL can
then be selected based on this characteristic(s). One or more of
the patient lifestyle parameters and/or eye factors may be weighted
by the processor 56 for priority consideration (e.g., to determined
the desired characteristic of the candidate multifocal IOL) when
selecting or determining the particular multifocal IOL for the
patient. In this embodiment, the processor 56 includes a processing
module 58 that determines an add power based on the patient
lifestyle parameters and one or more eye factors. The module 58 may
be a separate processing unit from the processor 56 in other
embodiments.
[0041] In another embodiment, the system 50 may be communicate with
a laser system (not shown) that directs laser energy onto a surface
of the cornea according to a pre-determined ablation profile to
reprofile a surface of the cornea. This is particularly useful for
combined ophthalmic treatments to effect a desired optical
correction. For example, the ablation profile and the determined
multifocal IOL characteristics are together considered for
mitigating presbyopia associated with the patient's eye or for
implementing other optical corrections.
[0042] The present invention also provides methods of providing
improved ophthalmic lenses. In general, at least one characteristic
of the patient's eye is measured, and a multifocal intraocular lens
(e.g., a diffractive multifocal intraocular lens) is selected from
among a plurality of multifocal intraocular lenses having similar
IOL powers based on the measured characteristic of the eye of the
patient. At least some of these intraocular lenses have central
portions, and selection of the intraocular lens includes selecting
between different central portion sizes.
[0043] In one embodiment, the method includes determining a set of
patient lifestyle parameters for a patient (e.g., by measurements,
observations, and questionnaires from the patient or others in
contact with or having knowledge about the patient, or the like),
determining at least one eye factor for an eye of the patient
(e.g., via measurement, retrieved from a database, or the like),
determining an add power based on the lifestyle parameter(s) and
the eye factor(s), and selecting a multifocal intraocular lens for
the patient based on this add power. The eye factors can include an
axial length of the eye (e.g., for determining the add power in
response to a preferred reading distance and the axial length of
the eye), the corneal shape of the eye, the pupil diameter of the
eye under a predetermined viewing condition, a set of pupil
diameters of the eye under a set of predetermined viewing
conditions, a keratometry factor, and/or a corneal radius of
curvature factor. Additionally lifestyle parameters include, but
are not necessarily limited to, an amount of outdoor activity, an
amount of reading time, an amount of computer time, and a work
environment.
[0044] In another embodiment, based on at least one eye factor, a
base power of the multifocal intraocular lens is selected in
addition to a separate multifocal lens parameter (e.g., an amount
of add power, a depth of focus characteristic, an amount of
aberration selected to at least partially correct for an aberration
of the cornea of the patient's eye, a spectral transmission
characteristic, a pupil dependent add power function) for a
multifocal intraocular lens. Additional eye factors include, but
are not necessarily limited to, a patient age, a corneal shape, a
cataract grade, an estimated postoperative pupil diameter of the
eye under predetermined viewing conditions, or a pre-existing
intraocular lens.
[0045] An exemplary embodiment of a selection of a multifocal
intraocular lens includes determining at least one eye factor for
an eye of the patient. Based on the at least one eye factor, a base
power and/or a multifocal lens parameter is selected for a
multifocal intraocular lens. As a more specific example, for many
method embodiments, an IOL presbyopia-mitigating add power is
determined using a standard or customized near (e.g. reading)
viewing distance of the patient. However, the effectiveness of the
IOL add power is also determined by the patient's eye dimensions,
and primarily by the axial length of the eye. For an eye with an
average axial length, a 4 D add may, for example, deliver a near
focus at about 33 cm. For an eye with a longer axial length, the
desired add power may be larger. For a patient having a
substantially standard eye length of about 23.5 mm, with a
substantially standard cornea, a 21.7 D IOL base power may be
suitable. For this patient, a 4 D add results in a near distance of
about 32.1 cm. For an otherwise similar patient with similar
corneal characteristics and an eye with an axial length of about
27.5 mm, the anterior chamber depth will typically be larger, and
the patient may instead benefit from a base power of about 9.1 D.
To have a reading distance of about 32 cm, this other patient may
benefit from about a 5.1 D add power for mitigation of myopia. Note
that the base power is normally selected based on the axial length
of the eye and the corneal curvature (two eye factors).
[0046] Exemplary methods for customized mitigation of the
presbyopia of a particular patient will also often include
determining at least one patient lifestyle parameter of the
patient. Based on the at least one lifestyle parameter and the at
least one eye factor, a base power and a multifocal lens parameter
for a multifocal intraocular lens can then be selected. A more
specific example of such embodiments might be a patient who is an
active philatelist or stamp collector. Such a patient may, for
example, prefer to have a best near vision at a distance of about
20 centimeters. For this patient, an add power of about 5 D might
be chosen to achieve the best performance for this patient so as to
mitigate their presbyopia for their lifestyle. In contrast, a
patient who is an active golfer may wish to instead have a best
near vision at a distance of about 1.5 m. An add power of about 1 D
could be chosen to achieve an optimal performance for this patient.
Patients for whom day and/or night driving or other activities are
particularly important, or who would have different lifestyle
priorities that may impact their desired visual performance, may
similarly have their vision customized (i.e., via the selected
multifocal intraocular lens) in response to their lifestyle
parameters so as to effectively mitigate the impacts of presbyopia
on their lives.
[0047] While the exemplary embodiments have been described in some
detail, by way of example and for clarity of understanding, those
of skill in the art will recognize that a variety of modification,
adaptations, and changes may be employed. Hence, the scope of the
present invention should be limited solely by the appending
claims.
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