U.S. patent application number 15/465325 was filed with the patent office on 2017-07-06 for intraocular lenses for managing glare, adhesion, and cell migration.
The applicant listed for this patent is Abbott Medical Optics Inc.. Invention is credited to Jim Deacon, Rakhi Jain, Leander Zickler.
Application Number | 20170189168 15/465325 |
Document ID | / |
Family ID | 36653931 |
Filed Date | 2017-07-06 |
United States Patent
Application |
20170189168 |
Kind Code |
A1 |
Zickler; Leander ; et
al. |
July 6, 2017 |
INTRAOCULAR LENSES FOR MANAGING GLARE, ADHESION, AND CELL
MIGRATION
Abstract
An intraocular lens for providing vision to a subject contains
an optic, a support structure coupled to the optic. The intraocular
lens also includes a textured surface and/or subsurface layer. The
optic is disposed about an optical axis and comprises an anterior
surface and an opposing posterior surface, the surfaces being
configured to focus light when implanted within an eye having a
capsular bag. The textured surface is disposed over a surface
portion of the intraocular lens and includes a plurality of
periodically-spaced protrusions, each protrusion having a smooth
distal face and a sharp corner edge configured to engage a wall of
the capsular bag and/or at least one cell disposed along the wall.
The subsurface layer is configured to scatter an amount of light
that is at least twice the amount of light scattered by portions of
the material adjacent the subsurface layer or at least twice the
amount of light scattered by another intraocular lens that does not
have the subsurface layer, but which is otherwise substantially
equivalent.
Inventors: |
Zickler; Leander; (Menlo
Park, CA) ; Jain; Rakhi; (Fort Worth, TX) ;
Deacon; Jim; (Goleta, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Abbott Medical Optics Inc. |
Santa Ana |
CA |
US |
|
|
Family ID: |
36653931 |
Appl. No.: |
15/465325 |
Filed: |
March 21, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14065137 |
Oct 28, 2013 |
9603702 |
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15465325 |
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|
11534200 |
Sep 21, 2006 |
8568478 |
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14065137 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2250/0053 20130101;
A61F 2002/1696 20150401; A61F 2250/0096 20130101; A61F 2220/0008
20130101; A61F 2220/0016 20130101; A61F 2002/009 20130101; A61F
2250/0098 20130101; H04W 52/146 20130101; A61F 2/1613 20130101;
H04W 52/367 20130101; A61F 2002/1681 20130101 |
International
Class: |
A61F 2/16 20060101
A61F002/16 |
Claims
1. An intraocular lens, comprising: an optic disposed about an
optical axis comprising an anterior surface and an opposing
posterior surface, the surfaces configured to focus light when
implanted within an eye of a subject; a support structure coupled
to the optic; and a periphery disposed about the optical axis
comprising a single material and including a top surface, a bottom
surface, and a subsurface layer disposed therebetween, the
subsurface layer configured to scatter an amount of light that is
at least twice the amount of light scattered by portions of the
material adjacent the subsurface layer or at least twice the amount
of light scattered by another intraocular lens that does not have
the subsurface layer, but which is otherwise substantially
equivalent.
2. The intraocular lens of claim 1, wherein the subsurface layer is
circumferentially disposed entirely about a central portion of the
optic.
3. The intraocular lens of claim 1, wherein the subsurface layer
forms a strip that surrounds the central portion of the optic.
4. The intraocular lens of claim 1, wherein the subsurface layer
has a radial width away from the optical axis and a thickness in a
direction along the optical axis.
5. The intraocular lens of claim 4, wherein the is greater than
about four times the thickness.
6. The intraocular lens of claim 1, wherein the subsurface layer
forms a contiguous strip that surrounds the central portion of the
optic.
7. The intraocular lens of claim 1, wherein the subsurface layer is
disposed within a plane that is orthogonal to the optical axis.
8. The intraocular lens of claim 1, wherein the subsurface layer
forms a conic section disposed about the optical axis.
9. The intraocular lens of claim 1, wherein the subsurface layer
forms an arcuate surface in a plane containing the optical
axis.
10. The intraocular lens of claim 1, wherein the subsurface layer
comprises a first layer and a second layer, at least a portion of
the second layer disposed directly above the first layer.
11. The intraocular lens of claim 1, wherein the subsurface layer
comprises portions of the material having a refractive index that
is different from the refractive index of portions of the material
adjacent the subsurface layer.
12. The intraocular lens of claim 1, wherein the subsurface layer
comprises a plurality of small voids within the material.
13. The intraocular lens of claim 1, wherein the subsurface layer
comprises a plurality of discontinuities.
14. The intraocular lens of claim 13, wherein discontinuities are
less than about 2 micrometers in diameter.
15. The intraocular lens of claim 1, wherein the subsurface layer
is formed by a plasma.
16. The intraocular lens of claim 1, wherein the subsurface layer
is formed by laser-induced optical breakdown within the
material.
17. The intraocular lens of claim 1, wherein the subsurface layer
is formed by a focused beam produced from near infrared,
ultra-short pulse of laser light.
18. An intraocular lens, comprising: an optic disposed about an
optical axis comprising an anterior surface and an opposing
posterior surface, the surfaces configured to focus light when
implanted within an eye having a capsular bag; a support structure
coupled to the optic; a periphery disposed about the optical axis
comprising a single material and including a top surface, a bottom
surface, and a subsurface layer disposed therebetween, the
subsurface layer configured to scatter an amount of light that is
at least twice the amount of light scattered by portions of the
material adjacent the subsurface layer or at least twice the amount
of light scattered by another intraocular lens that does not have
the subsurface layer, but which is otherwise substantially
equivalent; a textured surface disposed adjacent the subsurface
layer comprising a plurality of periodically-spaced
protrusions.
19. The intraocular lens of claim 18, wherein each protrusion
comprises a smooth distal face and a sharp corner edge configured
to engage a wall of the capsular bag and/or at least one cell
disposed along the wall.
20. The intraocular lens of claim 18, further comprising a
plurality of channels disposed between adjacent protrusions of the
plurality of periodically-spaced protrusions.
21. The intraocular lens of claim 18, wherein the textured surface
is configured to form a mono-layer of cells adjacent the textured
surface when the intraocular lens is placed in the eye.
22. The intraocular lens of claim 18, wherein the support structure
comprises a flexible positioning member coupled to the optic, the
flexible positioning member having an outer surface configured to
engage the capsular bag so as to produce accommodation in response
to an ocular force, the textured surface disposed over at least a
portion of the outer surface.
23. A method of making in intraocular lens, comprising: providing
an intraocular lens, including: an optic disposed about an optical
axis comprising an anterior surface and an opposing posterior
surface, the surfaces configured to focus light when implanted
within an eye of a subject; a support structure coupled to the
optic; and a periphery comprising a single material disposed about
the optical axis and including a top surface, a bottom surface;
forming a subsurface layer between the top surface and the bottom
surface that is configured to scatter an amount of light that is at
least twice the amount of light scattered by portions of the
material adjacent the subsurface layer or at least twice the amount
of light scattered by another intraocular lens that does not have
the subsurface layer, but which is otherwise substantially
equivalent.
24. The method of claim 23, wherein forming the substrate comprises
focusing laser light to form a localized variation in an index of
refraction.
25. The method of claim 23, wherein forming the substrate comprises
focusing laser light to produce laser-induced optical breakdown
within the single material.
26. The method of claim 23, forming a textured surface disposed
over a surface portion of the intraocular lens, the textured
surface comprising a plurality of periodically-spaced
protrusions.
27. An intraocular lens, comprising: an optic disposed about an
optical axis comprising an anterior surface and an opposing
posterior surface, the surfaces configured to focus light when
implanted within an eye of a subject; a support structure coupled
to the optic; and a volume comprising a single material; a
subsurface mark disposed within the volume that is configured to
scatter an amount of light that is at least twice the amount of
light scattered by portions of the volume adjacent the subsurface
mark.
28. The intraocular lens of claim 27, wherein the subsurface mark
is a symbol.
29. The intraocular lens of claim 27, wherein the subsurface mark
comprises one or more alphanumeric characters.
30. The intraocular lens of claim 27, wherein the subsurface mark
is configured to show at least one of the orientation of the
intraocular lens and the position of the intraocular lens.
31. The intraocular lens of claim 27, wherein the subsurface mark
is a reticle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of and claims priority to
U.S. application Ser. No. 14/065,137, filed Oct. 28, 2013, which is
a continuation application of U.S. application Ser. No. 11/534,200
filed on Sep. 21, 2006, now U.S. Pat. No. 8,568,478, which are all
incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] This invention relates generally to an intraocular lens and
more specifically to an intraocular lens configured to reduce
glare, improve adhesion to the eye, and/or mitigate unwanted cell
migration such as posterior capsule opacification (PCO).
[0004] Description of the Related Art
[0005] The implantation of intraocular lenses represents one of the
safest surgical procedures currently conducted and enjoys an
extremely high success rate. One common use of intraocular lenses
is for the replacement of natural lenses that have become clouded
due to the formation of cataracts. Intraocular lenses have also
found other uses, for example in the form of anterior chamber
lenses that are implanted just behind the cornea in order to
restore vision to patients that are extremely myopic or
hyperopic.
[0006] One set of problems that are frequently encountered in the
use of intraocular lenses is that of glare and posterior capsule
opacification (PCO). Glare problems can occur due to edge effects
from the implanted optic, which is typically much smaller than the
natural lens being replaced. For example peripheral light entering
the eye can be redirected by the edges of the optic, or even haptic
portions connected to the optic, back toward the central portion of
the field of view to create annoying and even dangerous glare
images that are superimposed with the normal image formed by the
center of the optic.
[0007] PCO typically occurs as a result of cells (epithelial cells)
that migrate from the equatorial regions of the capsular bag into
the optic portion of the intraocular lens. When this occurs, the
result can be a loss of vision that is similar to that caused by
the cataractous material that precipitated the surgery in the first
place.
[0008] Another problem that may occur when an intraocular lens is
implanted into an eye is that of poor adhesion of the intraocular
lens to the eye, for example, poor adhesion to the capsule walls of
a capsular bag into which the intraocular lens is placed. Good
adhesion between the intraocular lens and the capsular bag can, for
example, help maintain centration of the lens about the optical
axis. In addition, good adhesion about the periphery of an optic
may, at least in part, be important for reducing migration of
epithelial cells toward the center of the optic. Adhesion can be
particularly important in accommodating intraocular lenses, since
these types of lenses typically require that force from the ciliary
muscles and the capsular bag be effectively transferred to the
intraocular lens so that the lens can translate or deform when
changing between accommodative and disaccommodative states.
[0009] Various methods and device designs have been used to handle
the duo of maladies common to intraocular lens implants. Examples
include those disclosed in U.S. Pat. Nos. 6,162,249; 6,468,306; and
6,884,262, and U.S. Patent Application Number 2005/033422, all of
which are herein incorporated by reference.
[0010] In some cases a solution for one of these two problems may
actually exacerbate the other. For example, sharp corner edges
about the periphery have been found to generally reduce the problem
of PCO; however, such discontinuities may also have the unwanted
effect of increasing glare due to the scatter of entering the
intraocular lens from the peripheral field of view.
[0011] Further improvements and design options are needed for
reducing the problems of both glare and PCO in patients receiving
intraocular lens implants, as well as increase the adhesion of
intraocular lens implants to the capsular bag.
SUMMARY OF THE INVENTION
[0012] The present invention is broadly directed to devices and
methods that may be used to reduce the problems of glare and PCO
common to intraocular lenses and/or other ophthalmic devices such
as capsular rings. Embodiments of the present invention are also
generally directed to structures that enhance the ability of an
intraocular lens to adhere or bond to the eye, for example, to the
capsule walls of a capsular bag. Using embodiments of the current
invention, each of these problems may be addressed in such a way
that the solution to one of these problems does not exacerbate or
augment the other problem. For instance, an intraocular lens
comprising an optic and a support structure coupled to the optic
may be configured with one or more textured surfaces comprising a
plurality of periodically-spaced protrusions, each protrusion
having a smooth distal face and at least one sharp corner edge
configured to engage a capsule wall of the capsular bag and/or at
least one cell disposed along the capsule wall. In certain
embodiments, the textured surface may be configured to reduce glare
effects produced by light interacting with the peripheral edge of
an optic or a portion of a haptic. For example, the dimensions
and/or spacing of the protrusions may be selected to diverge or
scatter incident light and/or to produce optical interference.
[0013] In some embodiments, the texture surface comprises a
plurality of channels or grooves separated by a plurality of smooth
ridges. In other embodiments, the textured surface comprises a
plurality of pillars that are periodically disposed along the
surface in one or two dimensions. In yet other embodiments, the
textured surface comprises a plurality of rings that are
concentrically disposed about an optical axis of the intraocular
lens. In some embodiments, the textured surface comprises a
contiguous smooth surface with a plurality of periodically-spaced
wells disposed along the smooth surface, wherein a plurality of
sharp corner edges are formed at a plurality of intersections
between the smooth surface and the wells. The textured surface may
be configured to control or maintain cells (e.g., epithelial cells)
that come into contact with the textured surface in a favorable
state. A favorable cell state of the cells may include a state in
which the cells closely adhere to the textured surface or a state
in which cell proliferation or propagation is mitigated by
maintaining the cell in a form in which they are more contented and
less likely to divide to produce more cells (e.g., when the cells
are in a more spindle-like form, and not in a more spherical form).
In addition, the textured surface may be configured to provide
adhesion directly between the capsular bag and the textured
surface, even where no epithelial cells are present. The improved
adhesion provided by the textured surface, either directly or
indirectly (e.g., via epithelial cells remaining on the capsule
walls), may provide enhanced stabilization and centration of the
intraocular lens. In some embodiments, improved adhesion is used to
enhance the so-called "shrink wrap" effect produced as the capsular
walls adhere to one another in the vicinity of the intraocular
lens. This improved adhesion and the tendency of cells in contact
with the textured surface to not proliferate, either alone or in
combination, advantageously permits the textured surface to be used
to reduce the problem of PCO. Also, the improved adhesion provided
by the textured surface may be of particular importance in
accommodating intraocular lenses in which forces of the entire
capsular bag need to be transmitted to the intraocular lens in an
evenly distributed manner.
[0014] The textured surface may be disposed along any portion of
the intraocular lens where attachment to the capsular bag or cell
growth management is desired. The textured surface may be used in
conjunction with mono-focal lenses, multi-focal lenses, or
accommodating lenses, for example, to cause a structural element of
the intraocular lens to remain attached to the capsular bag during
accommodative movement thereof. In some embodiments, a cellular
mono-layer is formed that is able to impede or prevent the
migration of cells beyond the mono-layer.
[0015] In certain embodiments, the intraocular lens is
alternatively or additionally configured with a subsurface layer
that is disposed within an interior region of the intraocular lens
that is configured to reduce glare effects produced by incident
light. The subsurface layer may be located, for example, within a
periphery of the optic between a top surface and a bottom surface
or inside a portion of a haptic that is attached to the optic.
Preferably, the subsurface layer is configured to scatter light,
for example, to scatter an amount of light that is at least twice
the amount of light scattered by material adjacent the subsurface
layer. In some embodiments, the subsurface layer is a subsurface
mark that may be, for example, a symbol, one or more alphanumeric
characters, or reticle. Such a subsurface mark may be used to show
an orientation and/or position of the intraocular lens, to identify
the intraocular lens, and/or to provide one or more characteristics
of the intraocular lens (e.g., the focal length of the intraocular
lens).
[0016] The subsurface layer may be produced using a plasma that is
generated within the internal region of the intraocular lens and
that forms a plurality of localized micro-discontinuities having
refractive indices differing from the refractive index of material
adjacent the subsurface layer. The plasma may be created, for
example, by using a laser to create a laser-induced optical
breakdown (LIOB) condition.
[0017] Since the subsurface layer is located inside the intraocular
lens and is isolated from the outer surfaces of the intraocular
lens, it may be specifically structured to address glare issues
with no negative impact on cell migration. Conversely, the channels
discussed above may be configured independent of their potential
impact on glare, since a subsurface layer may be configured to
scatter or redirect light impinging on the channels.
[0018] Thus, embodiments of the present invention may be used, in
effect, to decouple the solutions to the problems of PCO and glare.
In certain embodiments, only one of the two solutions discussed
above need be incorporated, since the remaining problem in such
cases either is not particularly critical or is solved using a
different approach or solution.
[0019] Additional aspects, features, and advantages of the present
invention are set forth in the following description and claims,
particularly when considered in conjunction with the accompanying
drawings in which like parts may bear like reference numbers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Embodiments of the present invention may be better
understood from the following detailed description when read in
conjunction with the accompanying drawings. Such embodiments, which
are for illustrative purposes only, depict the novel and
non-obvious aspects of the invention. The drawings include the
following figures:
[0021] FIG. 1 is a top view of an intraocular lens according to an
embodiment of the present invention illustrating an anterior side
of an optic and a peripheral region that includes a subsurface
layer disposed below a surface of the intraocular lens.
[0022] FIG. 2 is a cross-sectional side view of the intraocular
lens illustrated in FIG. 1 across a section 2-2.
[0023] FIG. 3 is a magnified side view of the intraocular lens
illustrated in FIG. 1 across a section 3-3.
[0024] FIG. 4 is a further magnified side view of the intraocular
lens illustrated in FIG. 3 illustrating the details of a structured
surface for promoting capsular adhesion, optical control, and/or
control of cellular growth.
[0025] FIG. 5 is a top view of an intraocular lens according to
another embodiment of the invention.
[0026] FIG. 6 is a magnified side view of the intraocular lens
illustrated in FIG. 5 across a section 6-6.
[0027] FIG. 7 is a magnified side view of the intraocular lens
illustrated in FIG. 5 across a section 7-7.
[0028] FIG. 8 is a bottom view of the intraocular lens illustrated
in FIG. 7.
[0029] FIG. 9 is a perspective view of an accommodating intraocular
lens according to an embodiment of the present invention.
[0030] FIGS. 10a-10e are side views of intraocular lenses
illustrating various embodiments of a subsurface layer or layers
for scattering incident light.
[0031] FIG. 11 is a side view of an intraocular lens showing a
laser configured to produce a subsurface layer within the
intraocular lens.
DETAILED DESCRIPTION OF THE DRAWINGS
[0032] Embodiments of the invention are generally directed to
intraocular lenses for implantation within the posterior chamber or
capsular bag of an eye; however, novel embodiments of the invention
may also be applied, where appropriate, to intraocular lenses in
general (e.g., a phakic intraocular lens located in the anterior
chamber or a conical implant located within the cornea) or to other
ophthalmic devices (e.g., contact lenses or a capsular ring).
[0033] Referring to FIGS. 1-4, an intraocular lens 100 according to
an embodiment of the present invention is illustrated that
advantageously addresses the dual problems of unwanted cell
migration (e.g., PCO) and glare. The intraocular lens 100 comprises
an optic 102 disposed about an optical axis OA and has an anterior
surface 104 and an opposing posterior surface 108. The surfaces
104, 108 are configured to focus light onto the retina of an eye
into which the intraocular lens 100 is placed. The intraocular lens
100 further comprises a support structure 109 and a periphery or
peripheral region 110 disposed about the optical axis OA that
includes a top surface 112, a bottom surface 114, and a subsurface
layer 120 disposed between the top surface and bottom surfaces 112,
114. As discussed in greater detail below, the subsurface layer 120
may be configured to advantageously scatter or otherwise redirect
incident light so as to reduce glare on the retina of an eye into
which the intraocular lens 100 is placed. The subsurface layer 120
may also be configured for other uses such as for marking the
intraocular lens 100 for identification or providing a practitioner
information regarding the orientation or position of the
intraocular lens 100.
[0034] The peripheral region 110 may also include an outer surface
122 that is disposed substantially parallel to the optical axis OA.
The outer surface 122 may be straight, arcuate, or some combination
thereof when viewed in cross-section in a plane congruent with the
optical axis OA. In some embodiments, the outer surface 122 is also
configured to reduce glare and/or PCO, for example, as disclosed in
U.S. Pat. No. 6,884,262.
[0035] In the illustrated embodiment, the support structure 109
comprises two haptics 123. The haptics 123 may be used to center
the intraocular lens 100 within the eye of a subject and are
generally constructed to minimize damage to eye. In some
embodiments, the support structure is more complex than that shown
in the FIG. 1. In certain embodiments, the support structure
includes a structure that is configured to fill or substantially
fill a capsular bag and/or to provide accommodative action.
[0036] Referring to FIGS. 3-4, the intraocular lens 100 further
comprises a textured surface 128 disposed over a surface portion
129. The textured surface 128 may be advantageously configured to
address the problems of cell migration and/or glare. For example,
the textured surface 128 may be configured to maintain cells coming
into contact with the textured surface 128 in a favorable state
that prevents or reduces proliferation and/or propagation of cells
beyond the boundary of the textured surface 128. Alternatively or
additionally, the textured surface 128 may be advantageously
configured to adhere to the walls of a capsular bag by adhering to
the epithelial cells that remain on the capsule surface after the
natural lens of the eye has been removed. In certain embodiments,
the structured surface 128 is configured to provide adhesion
directly with the capsule wall, even where no or few epithelial
cells are present. While the textured surface is located on the
periphery 110 of the optic 102, it may be disposed on any surface
of the intraocular lens 100, including the optic 102.
[0037] The textured surface 128 comprises a plurality of
periodically-spaced protrusions 130, each protrusion 130 having a
smooth distal face 132 and at least one sharp corner edge 134
configured to engage a wall of the capsular bag (not illustrated)
of a subject and/or at least one cell disposed along the capsule
wall. The protrusions extend from the surface portion by an amount
that is between about 0.1 micrometer and about 2 micrometers,
preferably between 0.3 micrometers and 1 micrometer, more
preferably by about 0.5 micrometers,
[0038] In certain embodiments, the textured surface 128 is
configured to reduce glare effects produced by light interacting
with the optic 102, the periphery 110, and/or the support structure
109. For example, the dimensions and/or spacing of the protrusions
130 may be selected to diverge or scatter incident light and/or to
produce optical interference. Also, in some embodiments, while the
smooth distal faces 132 are generally smooth, the roughness or
structure of the surface portion 129 may be selected to be rough or
otherwise structured to produce a predetermined characteristic, for
example, to scatter or redirect light incident thereon so as to
reduce glare.
[0039] The sharp corner edges 134 preferably have a radius that is
less than about 200 nanometers, more preferably less than 100
nanometers, and even more preferably less than 20 nanometers. The
radius of the corners formed between the support structure 109 and
the protrusions 130 may be substantially equal to those of the
sharp edge corners 134. However, the radius of these corners may be
greater than those of the sharp edge corners 134 without adverse
affect, for example, in order to increase the manufacturability of
the structured surface 128.
[0040] The smooth distal faces 132 generally have an RA surface
roughness that is less than about 200 nanometers, preferably less
than 50 nanometers, even more preferably less than about 20
nanometers. The roughness of the other surfaces of the textured
surface 128 (e.g., the surface portion 129) may be greater than
that of the smooth distal faces 132.
[0041] In the illustrated embodiment, the plurality of protrusions
130 comprises a plurality of pillars and the smooth distal faces
132 are circular; however, other shapes and configurations of the
protrusions 130 are possible (e.g., smooth distal faces 132 may be
rectangular, oval, or some other shape; the protrusions 130 may be
configured to form concentric rings, as discussed below herein).
Each protrusion 130 may further comprise a side wall 136, such that
the sharp corner edge 134 is formed along an intersection of the
side wall 136 and the smooth distal face 132. The sharp corner
edges 134 are generally substantially perpendicular to the smooth
distal face 132. The side walls 136 and the smooth distal faces 132
form an angle that is generally between about 60 degrees and about
120 degrees and is preferably about 90 degrees.
[0042] Each smooth distal face 132 has a width w and is disposed
along the surface portion 129 with a center-to-center spacing L
between adjacent distal faces 132. The width w is generally between
about 1 micrometer and about 10 micrometers, preferably between 1
micrometer and 5 micrometers, and even more preferably between 1
micrometer and 4 micrometers. The ratio of the width w to the
center-to-center spacing L is generally between about 0.4 and about
0.7, with a ratio of about 0.5 being preferable in certain
embodiments. In some embodiments, for example, when the
center-to-center spacing is relatively large, the ratio of the
width w to the center-to-center spacing L may be as great as 0.8 or
more.
[0043] In some embodiments, the textured surface 128 comprises an
essentially inverse pattern to that illustrated in FIG. 4. That is
to say, the textured surface 128 may comprise a contiguous smooth
surface with a plurality of periodically-spaced wells or voids
disposed along the smooth surface in one or more directions. In
such embodiments, a plurality of sharp corner edges are formed at
the intersections between the smooth surface and the wells.
[0044] The textured surface 128 may be disposed at various
locations upon an intraocular lens according to embodiments of the
present invention. For example, referring to FIGS. 5-8, an
intraocular lens 200 comprises an optic 202, a pair of haptics 223,
and a periphery or peripheral region 210. The intraocular lens 200
further comprises a textured surface 228 that may be disposed both
within the peripheral region 210 and along at least a portion of
the haptics 223 adjacent the peripheral region 210. The textured
surface 228 may run contiguously between the peripheral region 210
and haptics 223, as illustrated in FIG. 8. Alternatively or
additionally, one or more textured surfaces 228' (not shown) may be
formed on one or more portions of the haptics 223 that are separate
from the textured surface 228 formed within the peripheral region
210. In some embodiments, the textured surface 228' is formed on
the haptics 223 and there is no textured surface formed within the
peripheral region 210.
[0045] The intraocular lens 200 further comprises a textured
surface 228a disposed on outer surface 222 of the periphery 210 and
a textured surface 228b disposed on an anterior surface 212 of the
optic 202. The additional textured surfaces 228a, 228b may be used
to further provide adhesion between the capsular bag and the
intraocular lens 200, for example, by causing the anterior capsule
to adhere to the anterior surface of the peripheral region 210. The
textured surfaces 228, 228a, and/or 228b may be separated from one
another (as illustrated in FIG. 6) or be contiguous with one
another to form a single textured surface.
[0046] One or more of the textured surfaces 228, 228a, 228b may
form an annular ring that completely surrounds the center of the
optic 202. Alternatively, one or more of the textured surfaces 228,
228a, 228b form an annular ring that is broken at predetermined
locations.
[0047] Referring to FIGS. 7-8, textured surface 228 comprises a
plurality of equally-spaced channels or grooves 240 separated by a
plurality of smooth ridges 242. The smooth ridges 242 are generally
smooth so as to maintain cells in a favorable state, reduce glare,
and/or to provide adhesion between the intraocular lens 200 and a
capsular bag. The textured surface 228 may be used alone or in
combination with a subsurface layer such as the subsurface layer
120 in order to reduce or eliminate both PCO on the optic 202 and
the formation of glare patterns on the retina of the eye due to
light entering the eye from peripheral fields of view.
[0048] In some embodiments, the textured surface 228 completely
surrounds the central portion 248 of the optic 202. In such
embodiments, the textured surface 228 may form a mono-layer of
cells that may act as a barrier that is effective in impeding or
completely preventing the migration of epithelial cells inside the
optic 202 when the intraocular lens 200 is implanted into the eye
of a subject. Alternatively, the channels 240 may be configured
radially or with some orientation or pattern, while the overall
shape of the textured surface 228 is disposed circumferentially
about the optic 202.
[0049] In the illustrated embodiment shown in FIGS. 7-8, the
textured surface 228 is circumferentially disposed about the optic
202 and has an over all radial length L2 that is greater than about
100 micrometers and less than about 1 millimeter. In some
embodiments, the radial length L2 is less than 100 micrometer or
greater than 1 millimeter. For example, the radial length L2 may be
greater than 1 millimeter, so as to increase adhesion or prevent
propagation of cellular growth onto the posterior surface 208 of
the optic 202. In the illustrated embodiment, the textured surface
228 is disposed entirely and continuously about the optic 202 on a
surface portion 229 that follows the general form or contour of the
intraocular lens 200 in the vicinity of the textured surface 228.
The surface portion 229 may be flat, curved, or arcuate in
shape.
[0050] The channels 240 have depth D, a width W.sub.C, and may be
disposed periodically with a period P. The depth D of the channels
240 is generally less than about 2 micrometer, in some instances
preferably less than or equal to about 0.5 micrometer. The width
W.sub.C of the channels 240 and a width W.sub.R of the smooth
ridges 242 is generally between about 1 micrometer and about 10
micrometers, preferably between 1 micrometer and 5 micrometers, and
even more preferably between 1 micrometer and 4 micrometers. The
ratio of the width W.sub.R of the smooth ridges 242 to the period
spacing L is generally between about 0.4 and about 0.7, with a
ratio of about 0.5 being preferable in certain embodiments. In some
embodiments, for example, when the center-to-center spacing is
relatively large, ratio of the width w to the center-to-center
spacing L may be as great as 0.8 or more.
[0051] The smooth ridges 242 generally have an RA surface roughness
that is less than about 200 nanometers, preferably less than 50
nanometers, even more preferably less than about 20 nanometers. The
roughness of the other surfaces of the textured surface 228 may be
greater than that of the smooth ridges 242.
[0052] The walls of the channels 240 preferably intersect the
smooth ridges to form sharp edge corners 234. The sharp corner
edges 234 preferably have a radius that is less than about 200
nanometers, more preferably less than 100 nanometers, and even more
preferably less than 20 nanometers. The radius of the corners
formed between the at the bottom of the channels 240 may be
substantially equal to those of the sharp edge corners 234;
however, the radius of these corners may be greater than those of
the sharp edge corners 134 without adverse affect, for example, in
order to increase the manufacturability of the structured surface
228.
[0053] It will be appreciated that the geometry and dimensions
discussed in relation to any one of the textured surfaces 128, 228,
228a, or 228b may, where appropriate, also be applied to any one of
the other textured surfaces 128, 228, 228a, or 228b, or any other
embodiment of a textured surface according to the present
invention.
[0054] Textured surfaces according to embodiments of the present
invention may be used in accommodating intraocular lenses, for
example, to provide adhesion between the support structure or
positioning member of an intraocular lens and the walls of the
capsular bag. Such accommodating intraocular lenses are disclosed,
for example, in U.S. Pat. Nos. 6,488,708, 6,494,911, or 6,761,737,
and in U.S. Patent Application Publication Numbers 2004/0082994 and
2004/0111153, which are all herein incorporated by reference. In an
exemplary embodiment illustrated in FIG. 9, a bag filling
accommodating intraocular lens 300 comprises a flexible positioning
member 301 coupled to an optic 302. The flexible positioning member
301 has an outer surface 304 configured to engage the capsular bag
so as to produce accommodation in response to an ocular force. As
used herein, the term "ocular force" means any force produced by
the eye of a subject that stresses, moves, or changes the shape of
an optic or intraocular lens that is placed in the eye of a
subject. The ocular force acting on a lens may be produced, for
example, by the state or configuration of the ciliary body (e.g.,
contracted or retracted), changes in the shape of the capsular bag
of the eye, stretching or contraction of one or more zonules,
vitreous pressure changes, and/or movement of some part of the eye
such as the ciliary body, zonules, or capsular bag, either alone or
in combination.
[0055] The textured surface 328 may be disposed over substantially
the entire outer surface 304, as illustrated in FIG. 9.
Alternatively, the textured surface may be applied only over
predetermined portions of the outer surface 304, such that portions
of the outer surface 304 are able to slide against the capsular bag
as it changes between accommodative and disaccommodative states.
For example the textured surface 328 may be selectively disposed
along an equatorial region 306.
[0056] The textured surface 328 is generally configured to produce
adhesion between the capsular bag and the positioning member 301 so
that ocular forces produced by the eye (e.g., by the capsular bag)
may be effectively transferred to the positioning member 301 in
such a way that optic 302 is translated and/or deformed to produce
a predetermined amount of change in optical power. It will be
appreciated that sufficient adhesion to the capsular is generally
important for enabling and controlling both the amount of
accommodation and the quality of resultant image produced as the
optic 302 changes between accommodative and disaccommodative
states.
[0057] A textured surface according to the present invention may
also be applied to at least portions of the surface of an
intraocular lens having essentially no haptics or positioning
member. For example, as will be appreciated by one of ordinary
skill in the art, the textured surface may be applied to at least a
portion of an outer surface of a flexible bag or bladder of an
intraocular lens, wherein the bladder is filled with a resilient
fill material. An example of such an intraocular lens is
illustrated in FIG. 14 of U.S. Patent Application Publication
Number 2004/0082993, which is herein incorporated by reference. The
textured surface may be applied to specific portions of the outer
surface, for example, about an equatorial portion of the flexible
bag. Alternatively, the textured surface may be applied over large
portions of the flexible bag, for example, over all areas of the
outer surface of the flexible bag that are to contact the walls of
a capsular bag into which the intraocular lens is to be placed. In
any event, the textured surface generally covers a sufficient
portion of the flexible bag to permit the intraocular lens to
deform in conformance with deformations of the capsular bag as it
changes between accommodative and disaccommodative states.
[0058] The textured surfaces 128, 228, 228a, 228b may be produced
using one or more of a variety of known fabrication methods. For
simplicity, fabrication methods discussed herein are with reference
to the textured surface 128; however, it will be appreciated that
such methods may also be applied in the formation of the textured
surfaces 228, 228a, 228b, 328, or other textured surfaces according
to embodiments of the present invention. In some embodiments, the
textured surface 128 is produced by chemically etching the
periodically-spaced protrusions 130 along the surface portion 129.
In such embodiments, a mask may be disposed over the surface potion
129 to provide a plurality of exposed areas thereon. One or more
chemicals may be subsequently used to etch material from the
exposed areas. In other embodiments, a protective film is disposed
upon the mask and exposed areas of the surface portion 129. The
mask may then be removed and a subsequent chemical treatment used
to from the textured surface 128 by etching material from portions
of the surface portion 129 not protected by the protective film. In
yet other embodiments, a laser similar to that used in forming the
subsurface layer 120 is used to etch or form the textured surface
128.
[0059] Alternatively or in addition to etching material to from the
surface portion 129, material may be deposited onto the surface
portion 129 in forming the textured surface 128. For example, the
protrusions 130 illustrated in FIG. 4 may be formed by applying one
or more layers onto the surface portion 129 (e.g., using a chemical
vapor deposition process). In some embodiments, the textured
surface 128 is formed by an embossing process or by machining the
desired features from the surface portion 129, for example, by
using a CNC lathe with milling capabilities. In other embodiments,
the textured surface 128 is formed by molding or by a combination
of machining and molding.
[0060] When an intraocular lens according to embodiments of the
present invention has both a textured surface 128 and one or more
subsurface layers 120, the textured surface 128 may be formed
either before or after formation of the subsurface layer 120. In
some embodiments, the textured surface 128 is disposed directly
above or below the subsurface layer 120, for example within the
peripheral region 110 surrounding the optic 102.
[0061] Referring again to FIGS. 1-3, the subsurface layer 120 may
be used to reduce glare potentially caused by light that might
otherwise be reflected by the periphery 110 and redirected toward
the central field of view of the eye. As illustrated in FIG. 3, the
subsurface layer 120 is configured to produce diffuse or scattered
light 134 when illuminated by a beam of light 146. In general, the
amount of scattered light 134 may be characterized by a scattering
cross-section that indicates the amount of light from an incident
beam that is scattered by the subsurface layer 120. As shown in the
illustrated embodiment, the subsurface layer 120 may be
circumferentially disposed entirely about a central portion 148 of
the optic 102. In some embodiments, the periphery 110 comprises a
single material that, apart from the subsurface layer 120, is
homogeneous throughout. Alternatively, the subsurface layer 120 may
form a separation between two different materials that form the
periphery 110.
[0062] In some embodiments, the subsurface layer 120 is configured
to scatter an amount of light that is at least twice the amount of
light scattered by portions of the material adjacent the subsurface
layer 120, more preferably at least 4 times the amount of light
scattered by portions of the material adjacent the subsurface layer
120, and even more preferably 10 times the amount of light
scattered by portions of the material adjacent the subsurface layer
120. In other embodiments, the subsurface layer 120 is configured
to scatter an amount of light that is at least twice the amount of
light scattered by an intraocular lens that does not have a
subsurface layer such as the subsurface layer 120, but which is
otherwise substantially equivalent to the intraocular lens 100. In
yet other embodiments, the subsurface layer 120 is configured to
scatter an amount of light that is at least 4 times, more
preferably 10 times the amount of light scattered by an intraocular
lens that does not have a subsurface layer such as the subsurface
layer 120, but which is otherwise substantially equivalent to the
intraocular lens 100. In some embodiments, the amount of light
scattered by the subsurface layer 120 is determined by illuminating
at least a portion of the subsurface layer 120 with a beam of
light, such as a laser beam, and measuring the amount of light
received by a photodetector having a predetermined area and
disposed, for example, 10 centimeter to 1 meter or more from the
intraocular lens 100. The amount of light received by the
photodetector may then be compared to the amount of light received
by the photodetector under a reference condition, for example, by
removing the intraocular lens 100 or replacing the intraocular lens
100 by an intraocular lens that does not have a subsurface layer,
but which is otherwise substantially equivalent to the intraocular
lens 100.
[0063] As illustrated in FIG. 1, the subsurface layer 120 may form
a contiguous strip that completely surrounds the central portion
148 of the optic 102. This configuration of the subsurface layer
120 advantageously scatters light intercepting the periphery region
110 of the intraocular lens 100. Alternatively, the subsurface
layer 120 may be circumferentially broken along one or more
regions.
[0064] In FIG. 3, the subsurface layer 120 is disposed within a
plane that is orthogonal to the optical axis OA and has a radial
width L1 in a direction away from or perpendicular to the optical
axis OA. In some embodiments, the radial width L1 of the subsurface
layer 120 may be clearly delineated by distinct inner and outer
edges. In other embodiments, the radial width L1 may be estimated
if inner and/or outer edges are less distinct, for example, if the
subsurface layer 120 has a scattering cross-section that is a
Gaussian in a radial direction. The thickness of the subsurface
layer 120 in a direction along the optical axis OA may be
relatively thin, as shown in FIG. 3, or may be thicker in order to
increase the scattering cross-section of the subsurface layer 120.
Generally, the radial width L1 is greater than about four times the
thickness. In certain embodiments, the radial width is at least 100
micrometers, while in other embodiments, the radial width L1 is at
least 200 micrometers, 500 micrometers, or 1 millimeter or
more.
[0065] The subsurface layer 120 may be disposed at or near the top
surface 112 of the peripheral region 110, as illustrated in FIG. 3.
Alternatively, the subsurface layer may be disposed at other depths
beneath the top surface 112, for example, at or near the bottom
surface 114 or approximately equidistant between the surfaces 112,
114. The location will generally be predicated on such factors as
ease of fabrication or scattering characteristics as a function of
layer depth.
[0066] Other configurations and distributions of the subsurface
layer 120 besides that illustrated in FIG. 3 are possible. For
example, in FIG. 10a, an intraocular lens 100a comprises a
peripheral region 110a having a subsurface layer 120a that forms a
conic section in which the subsurface layer 120a is oriented at an
angle relative to the optical axis OA. The angle .theta. may be
selected to provide a particular light scattering characteristic
(e.g., scattering cross-section or angular distribution of the
light scattered) that reduces the amount of glare produced by
peripheral light. Referring to FIG. 10b, an intraocular lens 100b
comprises a peripheral region 110b having a subsurface layer 120b
that is disposed to form a cylindrical surface that is oriented
parallel to an optical axis or an outer surface 122b. Referring to
FIG. 10c, an intraocular lens 100c comprises a peripheral region
110c having a subsurface layer 120c that is disposed to form an
arcuate shape when viewed in cross-section in a plane congruent
with the optical axis OA.
[0067] Referring to FIG. 10d, in certain embodiments, an
intraocular lens 100d comprises a peripheral region 110d having at
least two subsurface layers 120d and 120d' configured to provide a
predetermined scattering characteristic, for example, causing light
entering the peripheral region 110d to be multiply scattered. In
the illustrated embodiment, the subsurface layer 120d' is parallel
to an optical axis of the intraocular lens 100d, while the
subsurface layer 120d is perpendicular to the optical axis. In such
embodiments, at least some of the light directed toward an outer
surface 122d of the peripheral edge 110d is reflected and scattered
by the subsurface layer 120d. At least some of the reflected light
is subsequently diffusely scattered by the subsurface layer 120d'.
Referring to FIG. 10e, an intraocular lens 100e comprises at least
two subsurface layers 120e, 120e' that are disposed parallel to one
another so that at least some of the light entering the peripheral
region 110 is twice scattered, first by the subsurface 120d and
then by the subsurface 120d'. Additional subsurface layers may be
used may be used to further increase the amount of light scattered
and/or to increase the scattering cross-section for light entering
the peripheral region at one or more specific angles or ranges of
angles. For example, the subsurface layers 120d, 120d' or 120e,
120e' may be configured to scatter at least twice the amount of
light that would be scattered by the surface 120d or 120e alone if
illuminated by a beam of light. In some embodiments, two or more
subsurface layers are configured at one or more angles relative to
an optical axis (similar to the subsurface layer 120a in FIG. 10a)
or have a arcuate or more complex shape (similar to the subsurface
layer 120c in FIG. 10c).
[0068] The subsurface layer 120 may comprise a variety of
characteristics and mechanisms for scattering light in a
predetermined manner In some embodiments, the subsurface layer 120
comprises a variation in refractive index of the material within
the layer. The refractive index variations may be random or
pseudo-random in nature or may be more systematically structured to
scatter light in one or more preferred directions or with a
predetermined angular distribution. The subsurface layer 120 may be
configured so that the refractive index variations are along one
axis or along multiple axes, for example, in one or two directions
along the subsurface layer 120 and/or in a direction normal to the
subsurface layer 120. The variation in refractive index in one or
more directions may be continuous and/or characterized by localized
micro-discontinuities. For example, the refractive index variation
in one or more directions may be in the form of a plurality of
small voids, opaque particles or spots, and/or localized material
changes in the intraocular lens material. In general, the size of
such discontinuities is preferably on the order of a wavelength of
visible light, for example, about 2 micrometers or less, about 1
micrometer or less, or about 500 nanometers or less.
[0069] In some embodiments, the subsurface layer 120 may be
configured for alternative or additional purposes beside the
purpose of preventing or reducing glare on the retina. For example,
the subsurface layer 120 may be formed to produce one or more
shapes that may be used to identify the intraocular lens 100. In
such embodiments, the subsurface layer 120 may be configured to
form of one or more alphanumeric characters, symbols, or geometric
shapes such as squares, rectangles, triangles, circles, or
ellipses. Alternatively or additionally, one or more subsurface
layers may be configured to assist a practitioner to orient the
intraocular lens 100 prior to and/or after placement within the eye
of a subject. One example of such features to orient an intraocular
lens is found in US Patent Application Number 2005/149184, which is
herein incorporated by reference.
[0070] Referring to FIG. 11, in certain embodiments, a method of
producing the subsurface layer 120 comprises providing a laser 400
and using the laser to form a plasma within an interior portion 401
of the intraocular lens 100, for example, within the peripheral
region 110. The laser 400 may be any laser providing a beam that
can be sufficiently focused to produce a plasma, for example, a
near infrared (NIR), ultra-short pulse laser such as the
experimental system described by Leander Zickler, et al. in
"Femtosecond All-Solid State Laser for Refractive Surgery"
(Commercial and Biomedical Applications of Ultrafast Lasers III,
Proceedings of SPIE, Vol. 4978 (2003)), which is herein
incorporated by reference. Alternatively, the laser 400 may
comprise a commercial system such as the Coherent RegA 9000/9050
Ti:Sapphire regenerative amplifier available from Coherent Inc.
(Santa Clara, Calif., USA) or the IMRA FCPA microjoule D-1000
Ytterbium fiber oscillator/amplifier laser system available from
IMRA America Inc. (Ann Arbor, Mich., USA) or high-repetition rate,
cavity dumped, mode-locked ultrafast laser systems such as
femtoNOVA available from High Q Laser Production GmbH (Hohenems,
Austria). In certain embodiments, the laser 400 is able to produce
a pulse sequence of pulses having pulse widths of 10 to 100,000
femtoseconds, minimum pulse energies of 0.1 nJ to 100 micojoules,
temporal pulse separations of 10 ns to 100 microseconds, at a laser
wavelength of 200 nm to 2 microns. The use of lasers for this type
of material processing are described in greater detail in, for
example, U.S. Pat. No. RE 37,585, which is herein incorporated by
reference.
[0071] The laser 400 may be used to produce a beam 402 of light
that is expanded using expansion optics 404. Light from the beam
402 is directed to at least one focus 406 within the interior
portion 401 using a lens 410. The focus 406 preferably has a spot
size ranging from about 1 to about 100 microns. Alternatively, the
single lens 410 may be replaced by some other optical element or
optical system suitable for focusing laser light such as a mirror,
a diffractive optical element, or some combination of lenses,
mirrors, and/or diffractive optical elements that form a focus or a
plurality of foci. Preferably, the optical systems used to create
the focus 406 that creates a high energy density within a
relatively small volume, for example, by configuring the optical
system to have a high numerical aperture (NA). In certain
embodiments, the NA is between about 0.25 and about 1.2, preferably
greater than 0.5 or greater than 0.8, even more preferably greater
than or equal to about 1.
[0072] The laser light contained in the focus 406 provides an
energy or power density that is sufficient to produce a plasma
within the interior portion 401. An exemplary laser system for
producing such a plasma is discussed by Leander Zickler in the
Proceedings of SPIE, Vol. 4978 (2003) publication cited above
herein. Generally, the subsurface layer 120 is formed as a
condition of laser-induced optical breakdown occurs within the
material inside the interior portion 401. As the laser 400 is a
pulsed, the laser pulses create a plurality 413 of localized
micro-discontinuities 414, each of the micro-discontinuities 414
having an overall or average refractive index or effective
refractive index that is different from that of the surrounding
material.
[0073] In some embodiments, each of the micro-discontinuities 414
is in the form of a small volume in which the refractive index is
substantially constant, but is different from the refractive index
of material adjacent the subsurface layer 120. In other
embodiments, the refractive index within a micro-discontinuity 414
varies, for example, having a higher refractive index in the center
and a refractive index at a periphery that approaches or is
substantially equal to the refractive index of adjacent material.
In yet other embodiments, the micro-discontinuities 414 comprise
small cavities or voids that forms within the interior portion 401
of the intraocular lens 100.
[0074] In general, the localized difference in refractive index or
effective refractive index of the micro-discontinuities 414 causes
light incident to refract in a different direction or directions.
The combined effect of the plurality 413 of micro-discontinuities
414 is that at least some of the light incident upon the subsurface
layer 120 is scattered in a different direction. In some
embodiments, the subsurface layer 120 is configured to produce a
random or quasi-random scattering distribution of incident light by
randomly or quasi-randomly varying one or more properties of
different micro-discontinuities 414. The variation in property may
include, but not be limited to, the size of the
micro-discontinuities 414, the refractive index of the
micro-discontinuities 414, and the spacing between adjacent
micro-discontinuities 414. In addition, the plurality 413 of
micro-discontinuities 414 can be distributed at varying depths
within the interior portion 401 to produce multiple scattering of
light incident upon the subsurface layer 120. In some embodiments,
the absorption or transmissivity of the micro-discontinuities 414
may also be varied compared to the surrounding material or compared
to one another.
[0075] The method of producing the subsurface layer 120 further
comprises moving the focus 406 within the interior portion 401 so
as to from an extended area with a predetermined extent and
scattering cross-section. The extent, shape, number of the
subsurface layer(s) 120 formed by the focus 406 may be any of those
illustrated and discussed herein, such as those illustrated in
FIGS. 1, 3, and 10a-e, or any other form suited to provide a
desired scattering characteristic or cross-section.
[0076] The subsurface layer 120 may be formed by moving the focus
406 and/or intraocular lens 100 relative to one another by using,
for example, a scanning mirror, translation stage, and/or rotation
stage that is under computer control to provide a predetermined
pattern. In certain embodiments, hardware and control mechanisms
similar to those used in performing a LASIK or similar surgical
procedures may in adapted for use in the present application of
forming the subsurface layer 120. As an example for such system,
the IntraLase Pulsion FS60 available from IntraLase Inc. (Irvine,
Calif., USA), is cited. In the illustrated embodiment in FIG. 11,
the focus 406 moves along a straight line portion 412 and then
indexed circumferentially along a new line 412' (not shown).
Alternatively, the focus 406 may be moved in a more complex pattern
along the surface layer 120 being formed by the laser 400, for
example in a pattern similar to those used in modifying the corneal
surface in a LASIK surgical procedure. In some embodiments, several
passes may be made over the same position or area in order to
provide subsurface layer 120 with a particular scattering
characteristic. In addition, several passes may be made at varying
depths within the interior portion in order to increase the
thickness of the subsurface layer 120.
[0077] In some embodiments, the micro-discontinuities 414 are
evenly distributed, as illustrated in FIG. 11. Alternatively, the
micro-discontinuities 414 may be randomly distributed within the
plane of the subsurface layer 120 and/or along the thickness of the
subsurface layer 120. In addition, the density of the
micro-discontinuities 414 may be either constant throughout the
subsurface layer 120 or may vary over portions of the subsurface
layer 120. For example, the micro-discontinuities 414 may be evenly
distributed within a central portion or along an annular portion of
the subsurface layer 120, while density of the
micro-discontinuities 414 near boundary portions of the subsurface
layer 120 may decrease, for example as a Gaussian function.
[0078] In certain embodiments, the subsurface layer 120 may be
configured to systematically vary the refractive index or
transmissivity along the surface in way that causes incident light
to produce an interference pattern that diffracts or scatters at
least some the incident light in a predetermined manner This
variation may be constructed to redirect a predetermined portion of
the light (e.g., light at a particular wavelength or range of
wavelengths) in a particular direction so as to prevent or reduce
the formation of glare patterns on the retina. Additionally or
alternatively, the variation may be configured to cause incident
light to scatter with a predetermined angular distribution.
[0079] The above presents a description of the best mode
contemplated of carrying out the present invention, and of the
manner and process of making and using it, in such full, clear,
concise, and exact terms as to enable any person skilled in the art
to which it pertains to make and use this invention. This invention
is, however, susceptible to modifications and alternate
constructions from that discussed above which are fully equivalent.
Consequently, it is not the intention to limit this invention to
the particular embodiments disclosed. On the contrary, the
intention is to cover modifications and alternate constructions
coming within the spirit and scope of the invention as generally
expressed by the following claims, which particularly point out and
distinctly claim the subject matter of the invention.
* * * * *