U.S. patent application number 11/128824 was filed with the patent office on 2005-11-24 for corneal onlays and wavefront aberration correction to enhance vision.
This patent application is currently assigned to CooperVision, Inc. Invention is credited to Marmo, J. Christopher.
Application Number | 20050259221 11/128824 |
Document ID | / |
Family ID | 35451517 |
Filed Date | 2005-11-24 |
United States Patent
Application |
20050259221 |
Kind Code |
A1 |
Marmo, J. Christopher |
November 24, 2005 |
Corneal onlays and wavefront aberration correction to enhance
vision
Abstract
Devices and methods for improving vision are described. The
vision of a person can be corrected using a corneal onlay or a lens
positioned between an epithelial cell layer and Bowman's membrane
of the person's eye. Wavefront aberrations are measured for the
person's eye or eyes, and the aberrations are used to shape the
corneal onlay to provide a desired vision correction power, or to
shape the person's cornea.
Inventors: |
Marmo, J. Christopher;
(Danville, CA) |
Correspondence
Address: |
STOUT, UXA, BUYAN & MULLINS LLP
4 VENTURE, SUITE 300
IRVINE
CA
92618
US
|
Assignee: |
CooperVision, Inc
Pleasanton
CA
|
Family ID: |
35451517 |
Appl. No.: |
11/128824 |
Filed: |
May 13, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60573657 |
May 20, 2004 |
|
|
|
Current U.S.
Class: |
351/159.74 |
Current CPC
Class: |
A61F 2/145 20130101;
A61B 3/1015 20130101; A61F 2/147 20130101; B29D 11/023 20130101;
G02C 7/02 20130101; G02C 7/04 20130101 |
Class at
Publication: |
351/160.00R |
International
Class: |
G02C 007/04 |
Claims
What is claimed is:
1. A method for enhancing vision of an individual comprising:
measuring a wavefront aberration of an eye of an individual, the
eye comprising an epithelial cell layer and a Bowman's membrane;
and a step selected from the group consisting of: altering an
ocular implant element based on the measured wavefront aberration
to provide a correction for the wavefront aberration when the
altered ocular implant element is located in an eye between the
epithelial cell layer and the Bowman's membrane, and molding a
corneal onlay having an ocular power effective in correcting the
vision of an eye of an individual, and ablating a portion of the
eye of the individual to correct the measured wavefront
aberration.
2. The method of claim 1, wherein the ocular implant element is a
blank without a corrective ocular power or a lens having an optical
power.
3. The method of claim 1, wherein the ocular implant element is a
blank without a corrective ocular power or a lens having an optical
power, and the step of altering the ocular implant element
comprises ablating at least a portion of the blank or lens to
provide a correction for the wavefront aberration.
4. The method of claim 3, wherein the step of altering the ocular
implant element comprises ablating at least a portion of the blank
to provide a spherical power.
5. The method of claim 1, further comprising a step of placing the
altered ocular implant element or corneal onlay in the eye between
the epithelial cell layer and the Bowman's membrane.
6. The method of claim 5, further comprising a step of forming an
epithelial flap or epithelial pocket to facilitate placement of the
altered ocular implant element or corneal onlay in the eye.
7. A method of producing a corneal onlay, comprising: measuring a
wavefront aberration of an eye of an individual, the eye comprising
an epithelial cell layer and a Bowman's membrane; and a step
selected from the group consisting of: altering an ocular blank
without a corrective ocular power to provide a correction for the
wavefront aberration of the eye of the individual when the altered
ocular blank is located between the epithelial cell layer and the
Bowman's membrane, and altering at least a portion of a lens having
a fixed optical power to provide a correction for the wavefront
aberration of the eye of the individual when the altered lens is
located between the epithelial cell layer and the Bowman's
membrane.
8. The method of claim 7, further comprising a step of molding the
ocular blank or the lens from an ophthalmically acceptable
material.
9. The method of claim 7, wherein altering the ocular blank or the
lens comprises ablating at least a portion of the ocular blank or
the lens, respectively.
10. The method of claim 7, wherein altering the ocular blank or the
lens comprises ablating at least a portion of the blank or the lens
to have a spherical power, respectively.
11. A corneal onlay produced by the method of claim 7.
12. A method of producing a corneal onlay, comprising: altering an
ocular blank without a corrective ocular power or at least a
portion of a lens having a fixed optical power, to provide a
correction for a wavefront aberration of an eye of an individual
when the altered ocular blank or lens is located between an
epithelial cell layer and Bowman's membrane of the individual.
13. The method of claim 12, further comprising a step of: receiving
information regarding a wavefront aberration measured for the eye
of the individual.
14. The method of claim 12, further comprising a step of molding
the ocular blank or lens from an ophthalmically acceptable
material.
15. The method of claim 12, wherein altering the ocular blank or
lens comprises ablating at least a portion of the ocular blank or
lens, respectively.
16. The method of claim 12, wherein altering the ocular blank or
lens comprises ablating at least a portion of the blank or lens,
respectively, to have a spherical power.
17. A corneal onlay produced by the method of claim 12.
18. The method of claim 12, wherein altering the lens comprises
using a lathe to alter the lens.
19. The method of claim 18, wherein the lathe is used directly on
the lens, or on an insert for a mold configured to form a corneal
onlay.
20. The method of claim 19, wherein the lathe is used on a metal
insert for a thermoplastic mold.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Application No.
60/573,657, filed May 20, 2004, the content of which in its
entirety is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] The present invention relates to devices and methods of
enhancing the vision of an individual. In particular, the invention
relates to enhancing vision of an individual by measuring one or
more wavefront aberrations of the individual, and shaping an ocular
implant element into a corneal onlay that is configured to correct
for the wavefront aberration or aberrations.
SUMMARY OF THE INVENTION
[0004] The present invention relates to the use of corneal onlays
and wavefront technology to enhance an individual's (e.g., a person
or animal) vision, and to processes for making such onlays. Some
methods involve measuring one or more wavefront aberrations of an
individual, and altering an ocular implant element or the
individual's eye based on the wavefront aberrations.
[0005] In one embodiment, a method for enhancing vision of an
individual comprises: providing an ocular implant element, such as
a lens or a blank; measuring a wavefront aberration of an eye of an
individual; and altering the ocular implant element based on the
measured wavefront aberration to provide a correction for the
wavefront aberration when the altered ocular implant element is
located in an eye of the individual between the epithelial cell
layer and the Bowman's membrane. The ocular implant element may be
altered by ablating one or more portions of the element to form a
corneal onlay effective in correcting the wavefront
aberrations.
[0006] In another embodiment, a method for enhancing vision of an
individual comprises molding a corneal onlay having an ocular power
effective in correcting the vision of an eye of an individual;
measuring a wavefront aberration of the eye of the individual; and
ablating a portion of the onlay to correct the measured wavefront
aberration.
[0007] In another embodiment, a method for enhancing vision of an
individual comprises molding a corneal onlay having an ocular power
effective in correcting the vision of an eye of an individual;
measuring a wavefront aberration of the eye of the individual; and
ablating a portion of the eye of the individual to correct the
measured wavefront aberration.
[0008] The foregoing methods may also comprise a step of placing
the altered ocular implant element or the corneal onlay in the eye
between the epithelial cell layer and the Bowman's membrane. The
methods may also comprise forming an epithelial flap or forming an
epithelial pocket before placing the altered ocular implant element
or corneal onlay in the eye. The methods may also comprise placing
the epithelial flap over the altered ocular implant element or
corneal onlay positioned substantially on the Bowman's
membrane.
[0009] In another embodiment, a method of producing a corneal
onlay, comprises measuring a wavefront aberration of an eye of an
individual; and altering an ocular blank without a corrective
ocular power or a lens having an ocular power to provide a
correction for the wavefront aberration of the eye of the
individual when the altered ocular blank or altered lens is located
between the epithelial cell layer and the Bowman's membrane.
[0010] In another embodiment, a method of producing a corneal
onlay, comprises altering an ocular blank without a corrective
ocular power or a lens having a fixed optical power to provide a
correction for a wavefront aberration of an eye of an individual
when the altered ocular blank or lens is located between an
epithelial cell layer and Bowman's membrane of the individual.
[0011] The methods may also comprise molding the ocular blank or
lens from an ophthalmically acceptable material. The altering step
may comprise ablating one or more portions of the blank or lens.
For example, the methods may comprise using a lathe to alter the
blank or the lens to form the corneal onlay. The lathe may be used
directly on the blank or lens, or the lathe may be used on an
insert, such as metal insert, that makes or is used in making a
corneal onlay mold, such as a thermoplastic mold.
[0012] Any feature or combination of features described herein are
included within the scope of the present invention provided that
the features included in any such combination are not mutually
inconsistent as will be apparent from the context, this
specification, and the knowledge of one of ordinary skill in the
art. In addition, any feature or combination of features may be
specifically excluded from any embodiment of the present
invention.
[0013] Additional advantages and aspects of the present invention
are apparent in the following detailed description.
DETAILED DESCRIPTION
[0014] A typical human eye has a lens and an iris. The posterior
chamber is located posterior to iris and the anterior chamber is
located anterior to iris. The eye has a cornea that consists of
five layers, as discussed herein. One of the layers, the corneal
epithelium, lines the anterior exterior surface of cornea. The
corneal epithelium is a stratified squamous epithelium that extends
laterally to the limbus.
[0015] The five layers of the cornea include the corneal
epithelium, the Bowman's membrane, the stroma, Descemet's membrane,
and the endothelium. The corneal epithelium usually is about 5-6
cell layers thick (approximately 50 micrometers thick), and
generally regenerates when the cornea is injured. The corneal
epithelium provides a relatively smooth refractive surface and
helps prevent infection of the eye. The Bowman's membrane lies
between the epithelium and the stroma and is believed to protect
the cornea from injury. The corneal stroma is a laminated structure
of collagen which contains cells, such as fibroblasts and
keratocytes, dispersed therein. The stroma constitutes about 90% of
the corneal thickness. The corneal endothelium typically is a
monolayer of low cuboidal or squamous cells that dehydrates the
cornea by removing water from the cornea. An adult human cornea is
typically about 500 .mu.m (0.5 mm) thick and is typically devoid of
blood vessels.
[0016] The present invention relates to the use of corneal onlays
to enhance or improve vision in an individual, such as a person or
an animal. A corneal onlay is a lens with a vision-correcting or
vision-enhancing optical power and that is configured, such as
sized and shaped, to be placed between the epithelium and the
Bowman's membrane of an eye of an individual. Corneal onlays
include a major portion that is located between the epithelium and
Bowman's membrane. In some situations, a minor portion of the onlay
may penetrate Bowman's membrane and/or the underlying stroma. In
comparison, corneal inlays are configured to be placed in the
cornea, such as in the stroma of the cornea. In other words,
corneal inlays include a major portion that is placed in the
corneal stroma. Contact lenses are configured to be placed on the
epithelium of an eye.
[0017] In one aspect of the present invention, methods for
enhancing vision are disclosed which utilize a corneal onlay and
wavefront aberration measurements. In another aspect of the present
invention, method for producing or manufacturing corneal onlays are
disclosed.
[0018] One embodiment of the present methods of enhancing vision
comprises the steps of providing an ocular implant element,
measuring one or more wavefront aberrations of an eye of an
individual, and altering the ocular implant element based on the
measured wavefront aberration or aberrations to provide correction
for the wavefront aberration or aberrations when the altered ocular
implant element is located between the epithelial cell layer or
epithelium and the Bowman's membrane. The altered ocular implant
element may be understood to be a corneal onlay effective in
correcting or enhancing an individual's vision when the element is
placed between the epithelium and the Bowman's membrane.
[0019] The ocular implant element may be a blank, such as an
element without a substantial optical power, or an element with an
optical power of about 0 diopters. Or the ocular implant element
may be a lens, or in other words, an element with a desired or
pre-determined optical power, such as a vision correcting optical
power. The optical power of the lens may be determined for a
specific individual, or for a group of individuals.
[0020] The ocular implant element may be provided in a package of a
plurality of elements, or it may be provided in a package by
itself. The ocular implant element may be sterile or non-sterile.
Typically, the ocular implant element is provided by a manufacturer
of ophthalmic blanks or vision correcting lenses. The ocular
implant elements may be mass produced or may be produced and
provided based on an individual's needs and desires. In other
words, the ocular implant elements may be generically produced,
such as for ocular implant elements that do not have an optical
power, or for ocular implant elements that have a pre-determined or
fixed optical power. Or, the ocular implant elements may be
customized in their production to suit one or more individuals.
[0021] The ocular implant element comprises an ophthalmically
acceptable material. For example, the ocular implant element may be
produced from a material that is optically clear or otherwise does
not negatively affect or reduce an individual's vision when the
implant element is located on an eye of the individual. In
addition, the material from which the implant element is produced
provides for sufficient gas and nutrient exchange between the
Bowman's membrane and epithelium to maintain a viable, fully
functioning epithelium.
[0022] The material from which the ocular implant element is
produced may comprise a polymeric component comprising one or more
polymers. The polymers of the polymeric component may be synthetic
or naturally occurring, or both. Elements that comprise a plurality
of polymers may be formed by cross-linked polymers or
non-crosslinked but physically interwoven polymers.
[0023] In certain embodiments, the ocular implant element may be
made from collagen, such as purified collagen. The collagen may be
collagen Type I, which is the type of collagen that defines the
bulk of the corneal stroma, or the collagen may be non-Type I
collagen. Or the implant element may be made from combinations of
different types of collagen, such as types III, IV, V, and VII. The
collagen may be obtained from an animal source, for example, the
collagen may be human collagen, bovine collagen, porcine collagen,
avian collagen, murine collagen, equine collagen, among others.
Many different types of collagen useful in the lenses of the
present invention are publicly available from companies, such as
Becton Dickenson. Or, the collagen may be recombinantly
synthesized, such as by using recombinant DNA technology. One
source of publicly available recombinant collagen is FibroGen,
South San Francisco, Calif. Alternatively, or in addition,
recombinant collagen may be prepared and obtained using the methods
disclosed in PCT Publication No. WO 93/07889 or WO 94/16570. In
addition, the ocular implant element may be made from materials
described in one or more of the following: WO 2004/015090, WO
2004/014969, and WO 99/37752.
[0024] In addition, or alternatively, the ocular implant element
may be made from a polymeric hydrogel, as understood by persons of
ordinary skill in the art. A polymeric hydrogel includes a
hydrogel-forming polymer, such as a water swellable polymer. The
hydrogel itself includes such a polymer swollen with water.
Polymeric hydrogels useful in the present corneal onlays typically
have about 30% to about 80% by weight water, but may have about 20%
to about 90% by weight water, or about 5% to about 95% by weight
water, and have refractive indices between about 1.3 and about 1.5,
for example about 1.4, which is similar to the refractive indices
of water and a human cornea.
[0025] Examples of suitable hydrogel-forming polymer materials or
components of the disclosed ocular implant elements include,
without limitation, poly(2-hydroxyethyl methacrylate) PHEMA,
poly(glycerol methacrylate) PGMA, polyelectrolyte materials,
polyethylene oxide, polyvinyl alcohol, polydioxaline, poly(acrylic
acid), poly(acrylamide), poly(N-vinyl pyrilidone) and the like and
mixtures thereof. Many of such materials are publicly available. In
addition, one or more monomers which do not themselves produce
homopolymers which are not hydrogel-forming polymers, such as
methylmethacrylate (MMA), other methacrylates, acrylates and the
like and mixtures thereof, can also be included in such
hydrogel-forming polymer materials provided that the presence of
units from such monomers does not interfere with the desired
formation of a polymeric hydrogel.
[0026] Alternatively, the ocular implant elements may be
manufactured from a biocompatible, non-hydrogel material or
component, such as disclosed in U.S. Pat. No. 5,713,957. Examples
of non-hydrogel materials include, and are not limited to,
acrylics, polyolefins, fluoropolymers, silicones, styrenics,
vinyls, polyesters, polyurethanes, polycarbonates, cellulosics, or
proteins including collagen based materials. In addition, the
ocular implant element or the corneal onlay may comprise a cell
growth substrate polymer, such as those disclosed in U.S. Pat. No.
5,994,133.
[0027] Thus, the ocular implant elements may comprise a synthetic
material, a non-synthetic material, or a combination thereof. In
one embodiment, the ocular implant element is made entirely from a
synthetic material. In certain embodiments, the ocular implant
element is made from a combination of collagen and a synthetic
material, including, combinations of bovine collagen and a
synthetic material, and combinations of recombinant collagen and
synthetic materials. In additional embodiments, the lens may
include a poly(N-isopropylacrylamide- ) (polynipaam) component.
[0028] In reference to the disclosure herein, a corneal onlay
refers to a vision correcting lens that is suitable for placement
on an individual's eye to provide enhancements to the individual's
vision. The present corneal onlays may be produced by altering a
blank or a lens based on one or more wavefront aberrations of an
individual's eye or eyes, as described below.
[0029] The methods of enhancing vision may also comprise measuring
one or more wavefront aberrations of an eye of an individual. The
refractive error or errors in an eye may be measured using
wavefront technology, as is known to persons of ordinary skill in
the art. For example, a description of wavefront technology and the
measurements of wavefront aberrations is provided in U.S. Pat. No.
6,086,204 (Magnate) and WO 2004/028356 (Altmann).
[0030] A wavefront aberration is the three dimensional profile of
the distance between a real light wave front of a central spot of
light and a reference surface, e.g., an ideal spherical shape, as
shown in FIG. 1 of U.S. Pat. No. 6,585,375, and as described in
Mierdel et al., "Der Ophthalmologe", No. 6, 1997. A wavefront
aberration may be understood to be an optical path difference
between an actual image wavefront and an ideal reference wavefront
centered at an image point, at any point in the pupil of an eye.
Methods of measuring wave-front aberration are well known to
persons of ordinary skill in the art.
[0031] Briefly, and as described by Nader, N., Ocular Surgery News,
"Learning a new language: understanding the terminology of
wavefront-guided ablation" (Feb. 1, 2003), an aberrometer (e.g., an
instrument that measures the aberrations of an eye) may be used to
measure an aberrated image that leaves an eye, or may be used to
measure the shape of a grid projected onto the retina. For example,
while a patient is maintaining a view on a visual fixation target,
a relatively narrow input laser beam may be directed through the
pupil and focused onto the retina of the patient's eye to generate
a point-light source on the retina. The light is reflected from the
retina back through the pupil, and the wavefront of the light
passing from the eye is passed to a wavefront sensor. As understood
by persons of ordinary skill in the art, a wavefront can be defined
as a surface that connects all field points of an electromagnetic
wave that are equidistant from a light source. The light rays leave
the eye and may pass through an array of lenses that detects the
light rays' deviation. The wavefront gets deviated or distorted by
inhomogeneities in the refractive properties in the refractive
media of the eye, such as the lens, the cornea, the aqueous humor,
and the vitreous humor. The resulting image is then typically
recorded by a charge coupled device (CCD) camera, for example.
[0032] The wavefront is then typically reconstructed and the
deviations are described mathematically in three dimensions. The
wavefront deviations may be calculated, at least in part, by
analyzing the direction of the light rays. Generally, parallel
light beams indicate a wavefront with little, if any, aberrations,
and nonparallel light beams indicate a wavefront with aberrations
that do not give equidistant focal points.
[0033] Typically, Zernike polynomials are used to measure or
analyze the ocular aberrations. Each Zernike polynomial describes a
shape or a three-dimensional surface. As understood by persons of
ordinary skill in the art, Zernike polynomials are an infinite set,
but in ophthalmology, the Zernike polynomials are usually limited
to the first fifteen polynomials. Second-order Zernike terms
represent conventional aberrations, such as defocus and
astigmatism. Aberrations above second-order aberrations are called
higher-order aberrations. Higher-order aberrations typically cannot
be corrected by conventional spherocylindrical lenses. Examples of
higher-order aberrations include, but are not limited to, coma,
spherical aberrations, trefoil (wavefronts with threefold
symmetry), and quadrefoil (wavefront shapes with fourfold
symmetry). Many higher-order aberrations are not symmetrical, but
some higher-order aberrations, such as spherical aberrations, may
be symmetrical.
[0034] The refractive error measurements may be transmitted to a
lens-shaping machine or device, such as a computerized lathe, where
the shape of the ocular implant element is determined using the
information from the wavefront device. Other lathes may also be
used, such as non-computerized lathes. Other devices may include
one or more lasers that can be used to shape the ocular implant
element or a tool used to manufacture an ocular implant element. A
lathe may be used to alter the shape of the ocular implant element
by ablating one or more portions of the lens (e.g., the lathe acts
or is used directly on the ocular implant element), or by altering
the shape of an insert, such as a metal insert, that is used to
make a mold for a lens, such as a thermoplastic mold. Such inserts
are similar to inserts used in the manufacture of contact lenses,
as understood by persons of ordinary skill in the art. The shaped
ocular implant element that has been designed based on the
wavefront aberrations may be understood to be a corneal onlay.
[0035] In accordance with the present invention, the wavefront
aberration of an individual's eye may be measured and analyzed to
facilitate appropriate corneal onlay construction. The ocular
implant element (e.g., the blank or the lens) can then be shaped,
as discussed herein, taking into account any measured wavefront
aberrations. Thus, a corneal onlay is obtained with a lens body
configured to correct a wavefront aberration of a person's eye. The
wavefront aberration corrective surface may be provided on either
the anterior surface, the posterior surface, or both the anterior
and posterior surfaces. Thus, in certain embodiments, the present
onlays correct or reduce higher-order wavefront aberrations. In
situations where the higher-order wavefront aberrations are
asymmetrical, the lenses are configured to substantially maintain a
desired orientation to correct the wavefront aberrations.
[0036] After measuring the wavefront aberration or aberrations of a
person's eye, a method of enhancing vision of an individual
comprises altering the ocular implant element based on the measured
wavefront aberration. The altering is effective in providing a
correction for the wavefront aberration or aberrations when the
ocular implant element is located on an eye between the epithelial
cell layer and the Bowman's membrane.
[0037] As discussed herein, the altering step may comprise ablating
one or more portions of the ocular implant element. For example,
one or more portions of the ocular implant element may be ablated
or otherwise removed using a lathe, such as a computerized lathe, a
laser, or any other suitable lens-shaping device.
[0038] When the ocular implant element has no corrective ocular
power (e.g., a blank), or has a corrective ocular power (e.g., a
lens), ablation of at least a portion of the element is effective
to provide a correction for the wavefront aberration or
aberrations. The ablation may be effective to provide a spherical
power.
[0039] The method of enhancing vision described above may also
comprise a step of placing the altered ocular implant element (or
corneal onlay) in the eye of the individual between the epithelial
cell layer, such as the epithelium, and the Bowman's membrane. The
corneal onlay may be placed in the eye by first forming an
epithelial flap on the individual's eye, and then placing the
corneal onlay on the exposed Bowman's membrane. This method may
also comprise an additional step of placing the epithelial flap
over the corneal onlay when the onlay is positioned on the Bowman's
membrane. Or, the onlay may be placed in a pocket formed between
the epithelium or epithelial cell layer and the Bowman's membrane.
The corneal onlay may thus be positioned entirely between the
epithelium and Bowman's membrane.
[0040] The epithelial flap may be formed by removing a portion of
the epithelium using a separator that can separate the epithelium
from Bowman's membrane. One example of a separator is a
sub-epithelial separator developed by Dr. Ioannis Pallikaris
(Greece), such as the separator disclosed in U.S. Patent
Publication Nos. 2003/0018347 and 2003/0018348. The separator may
include a suction device, or ring, that can deliver suction to the
epithelium to cause the epithelium to be lifted from the cornea. A
cutting device, such as a blade, including a microkeratome, which
may or may not be a part of the separator can then be used to cut
the portion of the epithelium that is being lifted from the cornea
to create a flap, or to completely remove that portion of the
epithelium that is being manipulated.
[0041] Or the cutting device may use electromagnetic energy to cut
the epithelium. When electromagnetic energy is used as the
epithelial cutting device, it may be desirable to use an
electromagnetic energy source, such as a laser, with reduced, and
preferably no, thermal energy to help reduce cellular injury during
the procedure. For example, a fluid, such as water or saline, may
be used in conjunction with the electromagnetic energy to reduce
thermal damage caused by the electromagnetic energy. When removing
the corneal epithelium, it may be desirable to remove one or more
small portions of Bowman's membrane, as indicated herein to
facilitate more rapid healing of the ocular tissue. However, in
certain situations, the Bowman's membrane is left entirely
intact.
[0042] An epithelial pocket may be formed by making an incision in
the epithelium. An incision may be formed at any desired region
around the epithelium, but in preferred embodiments, the incision
or incisions is formed either in the temporal portion of the
epithelium (e.g., the portion of the epithelium that is located
away from the nose of a patient), or in the medial portion of the
epithelium. The incision is preferably formed to provide an opening
in the epithelium, for example, of suitable size, to accommodate a
corneal onlay to be inserted therethrough without creating an
epithelial flap. Typically, the incision will be formed away from
the pupil.
[0043] The incision can be made by cutting or slicing the
epithelium using a sharp instrument, such as a microkeratome and
the like, including the microkeratome disclosed hereinabove.
Alternatively, or in addition, the incision can be made by using
blunt dissection to separate epithelial cells to create an opening
in the epithelium without cutting or slicing the epithelium. Blunt
dissection provides an advantage of reduced injury to the
epithelial cells and/or epithelial tissue.
[0044] The onlay may then be inserted through the incision. The
onlay may be inserted by using forceps, or other similar device.
Or, the onlay may be inserted by using an inserter that is
configured to deform at least a portion of the onlay so that the
onlay can fit through the incision, for example, through a smaller
incision that would be necessary if the onlay was not deformed. For
example, the onlay may be folded or rolled or curled so that its
cross-sectional area is reduced while it is being inserted beneath
the epithelium. A corneal onlay insertion device may be a syringe
like device which includes a body with a distal end dimensioned to
pass the lens under the corneal epithelium of an eye. In certain
situations, the corneal onlay insertion device may be similar, or
at least somewhat similar, to well known and publicly available
intraocular lens inserters.
[0045] The epithelium may be raised prior to cutting the
epithelium. The epithelium may be raised using any suitable
technique that permits the epithelium to be separated from Bowman's
membrane preferably without substantially damaging Bowman's
membrane or the corneal stroma. In certain embodiments, a portion
of the epithelium is raised using a vacuum. The vacuum may be
provided with a microkeratome, such as with the separator disclosed
in U.S. Patent Publication Nos. 2003/0018347 and 2003/0018348, or
it may be provided as a separate instrument.
[0046] Alternatively, or in addition, the epithelium may be lifted
by delivering a fluid beneath a portion of the epithelium. The
delivery of fluid causes the epithelium to swell to create a bulge
of epithelial tissue that is spaced apart from Bowman's membrane,
as indicated above. One suitable fluid may include sodium chloride,
for example, an aqueous sodium chloride solution. Another fluid may
include a gel. The gel may be a gel that includes at least one
water soluble or water swellable polymeric material, for example,
at least one cellulosic component, such as hydroxymethylcellulose
and the like, and/or one or more other water soluble or water
swellable polymeric materials. In one specific embodiment, the
fluid comprises a gel sold as GENTEAL gel by CibaVision, Duluth,
Ga.
[0047] The present corneal onlays may also be inserted between an
epithelium and Bowman's membrane in a method comprising a single
step of forming an epithelial pocket and inserting the onlay at the
same time. For example, the onlay may be located on an epithelial
delaminator blade during a cutting procedure. After the pocket has
been formed, the onlay can be removed from the delaminator blade
and retained in the epithelial pocket as the delaminator blade is
removed from the pocket.
[0048] In another embodiment of the present invention, a method for
enhancing vision of an individual comprises molding an ocular
implant element to have an ocular power effective in correcting the
vision of an eye of a person, measuring the wavefront aberration of
the eye of the individual, and ablating a portion of the
individual's eye on which the molded ocular implant element is to
be placed to correct the measured wavefront aberration or
aberrations.
[0049] The foregoing method may also comprise a step of placing the
molded ocular implant element (e.g., corneal onlay) in the eye
between the epithelial cell layer and the Bowman's membrane, as
described herein. For example, the corneal onlay may be placed
under an epithelial flap, or it may be placed in an epithelial
pocket.
[0050] In another aspect of the present invention, a method of
producing a corneal onlay comprises measuring a wavefront
aberration or aberrations of an eye of an individual, and altering
a blank (e.g., an ocular implant element without an optical power)
to provide a correction for the wavefront aberration or aberrations
of the eye when the altered blank (e.g., corneal onlay) is located
between the epithelial cell layer and the Bowman's membrane.
[0051] Or, a method may comprise altering a blank or a lens based
on a wavefront aberration of an eye or eyes of an individual to
provide a correction for the wavefront aberration. Such a method
does not necessarily require a step of measuring a wavefront
aberration or aberrations of the eye. But, the method may comprise
a step of receiving information regarding the wavefront aberration
or aberrations of an eye or eyes of an individual. The information
could include results from a wavefront aberration measurement
procedure performed by a physician. The information could be
provided as printed results, or may be transmitted electronically
to an onlay manufacturer, which can then alter the blank or lens to
correct for the wavefront aberrations. For example, a physician
could measure wavefront aberrations of an eye of an individual, and
then transmit that information regarding the wavefront aberrations,
such as the type of aberrations or the location of the aberrations,
to an onlay manufacturer. The onlay manufactured can then produce
onlays that can provide the desired vision correction taking into
account the wavefront aberrations, in accordance with the present
invention.
[0052] The foregoing method may also comprise a step of molding the
blank from an ophthalmically acceptable material, as described
herein. The molding can be performed using any conventional molding
process similar or identical to the molding of contact lenses, as
understood by persons of ordinary skill in the art. As discussed
herein, the altering step may comprise ablating at least a portion
of the blank, which may be effective to provide a spherical power.
For example, the ablating can be accomplished utilizing a lathe, a
laser, or any lens altering machine or device, or combination of
devices.
[0053] When lasers are used, the laser can be delivered towards an
ablation zone or area of the blank or lens as a uniform number of
pulses, or in a pattern where the pulse density varies over the
ablation zone. One example of a suitable laser is the Star S4
excimer laser available from VISX.
[0054] The ablation of the blank or lens by a laser, lathe, or
other similar device, is effective in providing a desired
curvature, as discussed herein. The amount of the blank or lens
material removed can vary across the ablation zone, for example,
more material can be removed from a central portion relative to
peripheral portions. Or, more material may be removed from
peripheral portions relative to a central portion.
[0055] In another embodiment, a method of producing a corneal onlay
comprises measuring one or more wavefront aberrations of an
individual's eye or eyes, and altering at least a portion of a lens
(e.g., an ocular implant element having an optical power) to
provide a correction for the wavefront aberration or aberrations
when the altered lens (e.g., corneal onlay) is placed between the
epithelial cell layer and the Bowman's membrane.
[0056] The foregoing method may also comprise a step of molding an
ophthalmically acceptable material into the lens. Similar to the
methods above, the altering step may comprise ablating at least a
portion of the lens, for example, ablating at least a portion of
the lens to have a spherical power.
[0057] In view of the above, corneal onlays are disclosed that are
produced by any of the methods above. The present corneal onlays
and methods thus provide permanent yet reversible, if necessary,
vision enhancement.
[0058] The present corneal onlay has an anterior surface, a
posterior surface, a peripheral edge disposed at the juncture of
the anterior surface and the posterior surface. The anterior
surface is typically convex and the posterior surface is typically
concave, however, the posterior surface may also include one or
more planar portions or surfaces, or may be substantially
planar.
[0059] The corneal onlay may also include an optic zone and a
peripheral zone. Typically, the optic zone is bounded by the
peripheral zone, or in other words, the optic zone is generally
centrally located about an optical axis, such as a central optical
axis, of the lens and the peripheral zone is disposed between an
edge of the optic zone and the peripheral edge of the corneal
onlay. Additional zones and onlay configurations may be provided
with the onlay depending on the particular visual deficiency
experienced by the patient.
[0060] In addition, the present corneal onlays may have
junctionless zones, such as two or more zones that do not have a
visually or optically detectable junction. The zones of the onlays
may be smooth and continuous, and the onlays may be optically
optimized to correct not only refractive errors, but also other
optic aberrations of the eye and/or the optical device
independently or in combination with correcting refractive errors.
As understood by persons skilled in the art, corneal onlays may be
structured to correct visual deficiencies including, and not
limited to, myopia, hyperopia, astigmatism, and presbyopia. The
onlay may enhance or improve visual deficiencies by either optical
means or physical means imposed on the stroma of the eye, or a
combination thereof. Thus, the corneal onlay may be a monofocal
lens or a multifocal lens, including, without limitation, a bifocal
lens.
[0061] In addition, or alternatively, the corneal onlay may be a
toric lens. For example, the onlay may include a toric region which
may be effective when placed on an eye with an astigmatism to
correct or reduce the effects of the astigmatism. The onlay may
include a toric region located on the posterior surface of the
onlay, or the onlay may include a toric region located on the
anterior surface. A corneal onlay comprising a toric region may be
referred to as a toric onlay. The toric onlay does not necessarily
require a specific axis since the surgeon can align is the onlay to
the correct axis of the individual receiving the onlay. The axis is
typically used to align a cylinder of the lens to the patient based
on the inherent toricity of the individual's eye. Advantageously,
toric onlays without an axis, as described above, may provide a
reduced number of stock keeping units (SKUs) in manufacturing the
onlays. A toric onlay may comprise one or more markings, such as
provided on or in the onlay, or on a removable material attached to
the onlay, which are effective in showing where the cylinder is on
the onlay. Advantageously, toric onlays may be used without
requiring a ballast to maintain proper orientation of the onlay on
the eye since the onlay may be held in a relatively fixed position
by the epithelium of the appliance. However, a ballast may be
provided if desired. In certain embodiments, the onlay may include
a ballast, such as a prism, or it may include one or more thinned
regions, such as one or more inferior and/or superior thin zones.
In onlays configured to correct presbyobia, the onlay may include
one or more designs, such as concentric, aspheric (either with
positive and/or negative spherical aberration), diffractive, and/or
multi-zone refractive. One example of suitable corneal onlays is
disclosed in U.S. application Ser. No. 10/661,400, filed Sep. 12,
2003.
[0062] The corneal onlays disclosed herein may have an optical
power ranging from about -10.00 diopters to about +10.00 diopters,
although other optical powers may be provided, and such other
optical powers are within the scope of the present invention.
Typically, corneal onlay will have a diameter between about 5 mm
and about 12 mm. Preferably, the diameter of the onlay will be
between about 7 mm and about 10 mm. The optic zone of the onlay
typically ranges from about 5 to about 11 mm, and preferably ranges
from about 6 mm to about 8 mm, in diameter. The optic zone may be
provided on either the anterior or posterior surface of the
onlay.
[0063] The posterior surface of the corneal onlay is specifically
configured to substantially align with the anterior surface of a
de-epithelialized eye. Thus, the posterior surface of the onlay may
include one or more spherical or aspherical dimensions with a base
curve that ranges from about 5.0 mm to about 12.0 mm in diameter,
preferably from about 6.0 mm to about 9.0 mm, and more preferably
about 7.0 mm to about 8.5 mm. The thickness of the lens 40 at or
near the center of the lens (i.e., the center thickness) is
typically greater than about 10 micrometers and is less than about
300 micrometers. Preferably, the center thickness is between about
30 micrometers and about 200 micrometers. The exact or specific
thickness of the central region may be determined on a case-by-case
basis by one of ordinary skill in the art since the maximum
thickness is optical power and refractive index dependent.
[0064] The edge thickness of the corneal onlay is typically, but
not always, less than the center thickness of the onlay. The edge
thickness should be thin enough to facilitate epithelial cell
growth at the juncture of the onlay and the Bowman's membrane or
stroma of an eye, and may be thin enough to promote additional
epithelial cell migration over the edge of the onlay. Typically,
the edge thickness of the onlay is less than about 120 micrometers.
In certain embodiments, the onlay has an edge thickness less than
about 60 micrometers, and preferably less than about 30
micrometers. In a preferred embodiment, the lens 40 has an edge
thickness of about 0 micrometers (for example, the thickness of a
sharp knife edge). The onlay edge may be rounded on both the
anterior and posterior surfaces. Alternatively, the onlay edge may
include a rounded anterior surface and an apex on or near the
posterior surface. Or, the onlay edge may be shaped as a knife
edge.
[0065] In certain embodiments, the corneal onlay may also include a
cellular attachment element. The cellular attachment element
facilitates the stable positioning of an epithelial layer over the
onlay. Although cellular attachment elements may be desirable when
utilizing onlays fabricated from collagen, most cellular attachment
components may find increased use in the hydrogel or non-hydrogel
lenses described hereinabove.
[0066] Cellular attachment elements may include physical
perturbations of the onlay, such as indentations provided in the
anterior surface that facilitate cellular attachment and do not
alter the optical properties of the onlay. Indentations included
pores that extend through the lens from the anterior surface to the
posterior surface of the onlay. The indentations may be provided
over the entire onlay or over a fraction of the onlay. The
indentations may also be provided in specific patterns and
dimensions that facilitate cellular attachment of the epithelial
layer to the onlay.
[0067] The cellular attachment element may also comprise a polymer
that supports adhesion of the epithelial cells to the onlay. As
discussed above, the onlay may be made essentially from such
polymers as disclosed in U.S. Pat. No. 5,994,133. In addition,
these cell growth substrate polymers may be chemically bonded or
otherwise coated on the surface of a hydrogel or collagen based
onlay to facilitate cellular attachment to the onlay.
[0068] The cellular attachment element may also comprise a corneal
enhancer molecule, such as a corneal enhancer molecule that
specifically binds to a molecule present on the extracellular
surface of an epithelial cell. Examples of suitable corneal
enhancer molecules include peptides, such as the tri-peptide, RGD,
the pentapeptide, YIGSR, extracellular matrix proteins, corneal
growth factors, and ligand-specific corneal enhancer species, such
as laminin, fibronectin, substance P, fibronectin adhesion
promoting peptide sequence, FAP, insulin-like growth factor-1
(IGF-1), k-laminin, talin, integrin, kalinin, fibroblast growth
factor (FGF), and TGF-.beta., as disclosed in U.S. Patent
Publication No. U.S. 2002/0007217 A1. These corneal enhancer
molecules may include a tether, which may enhance the ability of
epithelial cells to attach and migrate over the onlay.
[0069] In one example, an ocular implant element may be
manufactured by molding a synthetic material, such as collagen, in
a lens mold having a desired structure to correct a visual
deficiency, thereby forming a lens. The collagen lens may be
modified on its surface to promote cellular attachment of the
epithelial cells. The collagen lens may then be altered to correct
one or more wavefront aberrations measured from an individual's eye
or eyes.
[0070] While this invention has been described with respect to
various specific examples and embodiments, it is to be understood
that the invention is not limited thereto and other embodiments are
within the scope of the invention.
[0071] A number of cited publications, patents, and patent
applications have been cited hereinabove. Each of the cited
publications, patents, and patent applications are hereby
incorporated by reference in their entireties.
* * * * *