U.S. patent application number 13/760782 was filed with the patent office on 2013-06-13 for method of implanting an intraocular lens.
This patent application is currently assigned to VISIOGEN, INC.. The applicant listed for this patent is Visiogen, Inc.. Invention is credited to Scott Evans, Luis Vargas, Reza Zadno.
Application Number | 20130150961 13/760782 |
Document ID | / |
Family ID | 36317352 |
Filed Date | 2013-06-13 |
United States Patent
Application |
20130150961 |
Kind Code |
A1 |
Evans; Scott ; et
al. |
June 13, 2013 |
METHOD OF IMPLANTING AN INTRAOCULAR LENS
Abstract
A method is provided for implanting an accommodating intraocular
lens system in a capsular bag of an eye. The method includes
providing the accommodating intraocular lens having an anterior
viewing element and a posterior viewing element. The anterior
viewing element has a width in a range between approximately 4.5
millimeters and approximately 6.5 millimeters. The method further
includes forming an opening in an anterior portion of the capsular
bag. The opening has a minimum width not less than approximately 4
millimeters and has a maximum width not greater than approximately
6.0 millimeters. The method further includes placing the
accommodating intraocular lens system within the capsular bag. The
capsular bag overlaps at least a portion of the anterior viewing
element and defines an overlap region with a width in a range
between approximately 0.1 millimeters and approximately 0.75
millimeters.
Inventors: |
Evans; Scott; (Santa Ana,
CA) ; Zadno; Reza; (Fremont, CA) ; Vargas;
Luis; (Irvine, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Visiogen, Inc.; |
Irvine |
CA |
US |
|
|
Assignee: |
VISIOGEN, INC.
Irvine
CA
|
Family ID: |
36317352 |
Appl. No.: |
13/760782 |
Filed: |
February 6, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10985854 |
Nov 10, 2004 |
8377123 |
|
|
13760782 |
|
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|
|
Current U.S.
Class: |
623/6.37 |
Current CPC
Class: |
B29D 11/023 20130101;
A61F 2/1648 20130101; A61F 2/1601 20150401; A61F 2/1627 20130101;
A61F 2/1629 20130101; A61F 2/1613 20130101 |
Class at
Publication: |
623/6.37 |
International
Class: |
A61F 2/16 20060101
A61F002/16 |
Claims
1. A method of implanting an accommodating intraocular lens system
in a capsular bag of an eye, the method comprising: providing an
accommodating intraocular lens, the accommodating intraocular lens
having a central region and a peripheral region, at least a portion
of the central region being optically transmissive; forming an
opening in an anterior region of the capsular bag; and placing the
accommodating intraocular lens within the capsular bag such that
the capsular bag extends inwardly from the peripheral region of the
intraocular lens towards the central region so that the capsular
bag overlaps with at least a portion of the central region and
defines an overlap region having a width AW, the width AW of the
overlap region having a size such that the intraocular lens is
properly positioned in the capsular bag.
2. The method of claim 1, wherein the width of the overlap region
is constant over the overlap region.
3. The method of claim 1, wherein the width of the overlap region
varies over the overlap region.
4. The method of claim 1, wherein the portion of the central region
that overlaps the capsular bag includes a plurality of fluid
conduits.
5. The method of claim 1, wherein the intraocular lens includes an
anterior viewing element and a posterior viewing element and the
central region includes a portion of the anterior viewing
element.
6. The method of claim 5, wherein the peripheral region includes an
anterior biasing element connected to the anterior viewing element
and a posterior biasing element connected to the posterior viewing
element, the anterior and posterior biasing elements meeting at
first and second apices.
7. The method of claim 6, wherein the anterior biasing element
includes a first anterior translation member extending from the
anterior viewing element to the first apex and a second anterior
translation member extending from the anterior viewing element to
the second apex.
8. The method of claim 1, wherein the accommodating intraocular
lens comprises at least one retention member configured to contact
at least a portion of the capsular bag and to space the portion of
the capsular bag from the central region.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is related to U.S. patent
application Ser. No. 10/207,701, filed Jul. 25, 2002 and U.S.
patent application Ser. No. 10/020,853, filed Dec. 11, 2001, each
of which is hereby incorporated by reference herein and made a part
of this specification. This application is a continuation of U.S.
Application No. 10/985,854, filed on Nov. 10, 2004, which is
incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to intraocular lenses and, more
particularly, to methods of implanting intraocular lenses that
alter the refractive power of the eye in response to changes in the
tension of the ciliary muscle of the eye.
[0004] 2. Description of the Related Art
[0005] The vast majority of cataract operations involve the
implantation of an artificial lens following cataract removal.
Typically these lenses have a fixed focal length or, in the case of
bifocal or multifocal lenses, have several different fixed
focal-lengths. Such fixed focal-length lenses lack the ability of
the natural lens to dynamically change the refractive power of the
eye. The various embodiments of the intraocular lens disclosed
herein provide an accommodating lens system which alters the
refractive power of the eye in response to changes in tension of
the ciliary muscle, thereby allowing the lens system to bring into
focus on the retina images of objects that are both near and far
from the eye.
SUMMARY OF THE INVENTION
[0006] In certain embodiments, a method is provided for implanting
an accommodating intraocular lens system in a capsular bag of an
eye. The method comprises providing the accommodating intraocular
lens. The accommodating intraocular lens has an anterior viewing
element and a posterior viewing element. The anterior viewing
element has a width in a range between approximately 4.5
millimeters and approximately 6.5 millimeters. The method further
comprises forming an opening in an anterior portion of the capsular
bag. The opening has a minimum width not less than approximately 4
millimeters and has a maximum width not greater than approximately
6.0 millimeters.
[0007] The method further comprises placing the accommodating
intraocular lens system within the capsular bag. The capsular bag
overlaps at least a portion of the anterior viewing element and
defines an overlap region with a width in a range between
approximately 0.1 millimeters and approximately 0.75
millimeters.
[0008] In certain embodiments, a method is provided for implanting
an intraocular lens system in a capsular bag of an eye. The method
comprises providing an accommodating intraocular lens system having
an anterior viewing element and a posterior viewing element. The
anterior viewing element has a first width. The method further
comprises forming an opening in an anterior portion of the capsular
bag. The opening has a second width. The second width is in a range
between approximately 0.2 millimeters less than the first width and
approximately 1.5 millimeters less than the first width.
[0009] In certain embodiments, a method is provided for implanting
an accommodating intraocular lens system in a capsular bag of an
eye. The method comprises placing an accommodating intraocular lens
system within the capsular bag. The intraocular lens system has an
anterior viewing element. The intraocular lens system is placed so
that at least a portion of the capsular bag overlaps at least a
portion of the anterior viewing element and defines an overlap
region. The overlap region has a width in a range between
approximately 0.1 millimeter and approximately 0.75 millimeter.
[0010] In certain embodiments, a method is provided for implanting
an intraocular lens in an eye. The method comprises providing an
accommodating intraocular lens having anterior and posterior
viewing elements. The anterior viewing element has a diameter in a
range between approximately 4.5 millimeters and approximately 6.5
millimeters. A portion of the anterior viewing element has
refractive power. The refractive anterior portion has a diameter in
a range between approximately 4 millimeters and approximately 5.5
millimeters. The anterior viewing element comprises a retention
member extending anterior of the anterior viewing element. The
method further comprises forming an opening in the anterior portion
of the capsular bag of the eye. The opening is sized so that (i) a
portion of the capsular bag contacts the retention member and
spaces the capsular bag from the anterior viewing element, and (ii)
the capsular bag extends inward from the retention member towards
the optical axis by no more than 1.25 millimeters.
[0011] For purposes of summarizing the invention, certain aspects,
advantages and novel features of the invention have been described
herein above. It is to be understood, however, that not necessarily
all such advantages may be achieved in accordance with any
particular embodiment of the invention. Thus, the invention may be
embodied or carried out in a manner that achieves or optimizes one
advantage or group of advantages as taught herein without
necessarily achieving other advantages as may be taught or
suggested herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Having thus summarized the general nature of the invention,
certain preferred embodiments and modifications thereof will become
apparent to those skilled in the art from the detailed description
herein having reference to the figures that follow, of which:
[0013] FIG. 1 is a sectional view of the human eye, with the lens
in the unaccommodated state.
[0014] FIG. 2 is a sectional view of the human eye, with the lens
in the accommodated state.
[0015] FIG. 3 is a perspective view of one embodiment of an
intraocular lens system.
[0016] FIG. 4 is a side view of the lens system.
[0017] FIG. 5 is a rear perspective view of the lens system.
[0018] FIG. 6 is a front view of the lens system.
[0019] FIG. 7 is a rear view of the lens system.
[0020] FIG. 8 is a top view of the lens system.
[0021] FIG. 9 is a side sectional view of the lens system.
[0022] FIG. 10 is a top sectional view of the lens system.
[0023] FIG. 11 is a second perspective view of the lens system.
[0024] FIG. 12 is a third perspective view of the lens system.
[0025] FIG. 13 is a side view of the lens system in the
unaccommodated state.
[0026] FIG. 14 is a side sectional view of the lens system in the
unaccommodated state.
[0027] FIG. 15 is a top sectional view of the lens system in the
unaccommodated state.
[0028] FIG. 16 is a sectional view of the human eye with the lens
system implanted in the capsular bag and the lens system in the
accommodated state.
[0029] FIG. 17 is a sectional view of the human eye with the lens
system implanted in the capsular bag and the lens system in the
unaccommodated state.
[0030] FIG. 17A is a sectional view of an arm of the lens
system.
[0031] FIG. 17B is a sectional view of another embodiment of the
arm of the lens system.
[0032] FIGS. 17C-17L are sectional views of other embodiments of
the arm of the lens system.
[0033] FIG. 17M is a side sectional view of another embodiment of
the lens system.
[0034] FIG. 17N is a side sectional view of another embodiment of
the lens system.
[0035] FIG. 18 is a side view of another embodiment of the lens
system.
[0036] FIG. 19 is a side sectional view of another embodiment of
the lens system.
[0037] FIG. 20 is a rear perspective view of another embodiment of
the lens system.
[0038] FIG. 21 is a partial top sectional view of another
embodiment of the lens system, implanted in the capsular bag.
[0039] FIG. 21A is a front view of another embodiment of the lens
system.
[0040] FIG. 21B is a front view of another embodiment of the lens
system.
[0041] FIG. 21C is a front view of another embodiment of the lens
system.
[0042] FIG. 22 is a partial side sectional view of another
embodiment of the lens system, implanted in the capsular bag.
[0043] FIG. 22A is a side view of a stop member system employed in
one embodiment of the lens system.
[0044] FIG. 23 is a side view of a mold system for forming the lens
system.
[0045] FIG. 24 is a side sectional view of the mold system.
[0046] FIG. 25 is a perspective view of a first mold portion.
[0047] FIG. 26 is a perspective view of a second mold portion.
[0048] FIG. 27 is a top view of the second mold portion.
[0049] FIG. 28 is a side sectional view of the second mold
portion.
[0050] FIG. 29 is another side sectional view of the second mold
portion.
[0051] FIG. 30 is a bottom view of a center mold portion.
[0052] FIG. 31 is a top view of the center mold portion.
[0053] FIG. 32 is a sectional view of the center mold portion.
[0054] FIG. 33 is another sectional view of the center mold
portion.
[0055] FIG. 34 is a perspective view of the center mold
portion.
[0056] FIG. 34A is a partial cross sectional view of an apex of the
lens system, showing a set of expansion grooves formed therein.
[0057] FIG. 35 is a schematic view of another embodiment of the
lens system.
[0058] FIG. 36 is a schematic view of another embodiment of the
lens system.
[0059] FIG. 37 is a perspective view of another embodiment of the
lens system.
[0060] FIG. 38 is a top view of another embodiment of the lens
system.
[0061] FIG. 38A is a schematic view of another embodiment of the
lens system, as implanted in the capsular bag.
[0062] FIG. 38B is a schematic view of the embodiment of FIG. 38A,
in the accommodated state.
[0063] FIG. 38C is a schematic view of biasers installed in the
lens system.
[0064] FIG. 38D is a schematic view of another type of biasers
installed in the lens system.
[0065] FIG. 38E is a perspective view of another embodiment of the
lens system.
[0066] FIGS. 39A-39B are a series of schematic views of an
insertion technique for use in connection with the lens system.
[0067] FIG. 40 is a schematic view of fluid-flow openings formed in
the anterior aspect of the capsular bag.
[0068] FIG. 40A is a front view of the lens system, illustrating
one stage of a folding technique for use with the lens system.
[0069] FIG. 40B is a front view of the lens system, illustrating
another stage of the folding technique.
[0070] FIG. 40C illustrates another stage of the folding
technique.
[0071] FIG. 40D illustrates another stage of the folding
technique.
[0072] FIG. 40E illustrates another stage of the folding
technique.
[0073] FIG. 40F illustrates another stage of the folding
technique.
[0074] FIG. 40G is a perspective view of a folding tool for use
with the lens system.
[0075] FIG. 41 is a sectional view of an aspheric optic for use
with the lens system.
[0076] FIG. 42 is a sectional view of an optic having a diffractive
surface for use with the lens system.
[0077] FIG. 43 is a sectional view of a low-index optic for use
with the lens system.
[0078] FIG. 44 is a side elevation view of another embodiment of
the lens system with a number of separation members.
[0079] FIG. 45 is a front elevation view of the lens system of FIG.
44.
[0080] FIG. 46 is an overhead sectional view of the lens system of
FIG. 44.
[0081] FIG. 47 is an overhead sectional view of the lens system of
FIG. 44, with the viewing elements at a minimum separation
distance.
[0082] FIG. 48 is a closeup view of the contact between a
separation member and an opposing surface.
[0083] FIG. 49 is a side sectional view of an apparatus and method
for manufacturing a center mold.
[0084] FIG. 50 is another side sectional view of the apparatus and
method of FIG. 49.
[0085] FIG. 51 is another side sectional view of the apparatus and
method of FIG. 49.
[0086] FIG. 52 is another side sectional view of the apparatus and
method of FIG. 49.
[0087] FIG. 53 is another side sectional view of the apparatus and
method of FIG. 49.
[0088] FIG. 54 is a side sectional view of the lens system in
position on the center mold.
[0089] FIG. 55 is a flow diagram of an exemplary method of
implanting an accommodating intraocular lens system in a capsular
bag of an eye in accordance with embodiments described herein.
[0090] FIGS. 56A-56F schematically illustrate various
configurations of an exemplary intraocular lens system oriented
within the capsular bag in a manner compatible with the method of
FIG. 55.
[0091] FIG. 57 schematically illustrates an exemplary intraocular
lens system, at least a portion of which contacts the capsular bag
58 in accordance with embodiments described herein.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
I. The Human Eye and Accommodation
[0092] FIGS. 1 and 2 show the human eye 50 in section. Of
particular relevance to the present disclosure are the cornea 52,
the iris 54 and the lens 56, which is situated within the elastic,
membranous capsular bag or lens capsule 58. The capsular bag 58 is
surrounded by and suspended within the ciliary muscle 60 by
ligament-like structures called zonules 62.
[0093] As light enters the eye 50, the cornea 52 and the lens 56
cooperate to focus the incoming light and form an image on the
retina 64 at the rear of the eye, thus facilitating vision. In the
process known as accommodation, the shape of the lens 56 is altered
(and its refractive properties thereby adjusted) to allow the eye
50 to focus on objects at varying distances. A typical healthy eye
has sufficient accommodation to enable focused vision of objects
ranging in distance from infinity (generally defined as over 20
feet from the eye) to very near (closer than 10 inches).
[0094] The lens 56 has a natural elasticity, and in its relaxed
state assumes a shape that in cross-section resembles a football.
Accommodation occurs when the ciliary muscle 60 moves the lens from
its relaxed or "unaccommodated" state (shown in FIG. 1) to a
contracted or "accommodated" state (shown in FIG. 2). Movement of
the ciliary muscle 60 to the relaxed/unaccommodated state increases
tension in the zonules 62 and capsular bag 58, which in turn causes
the lens 56 to take on a thinner (as measured along the optical
axis) or taller shape as shown in FIG. 1. In contrast, when the
ciliary muscle 60 is in the contracted/accommodated state, tension
in the zonules 62 and capsular bag 58 is decreased and the lens 56
takes on the fatter or shorter shape shown in FIG. 2. When the
ciliary muscles 60 contract and the capsular bag 58 and zonules 62
slacken, some degree of tension is maintained in the capsular bag
58 and zonules 62.
II. The Lens System: Structure
[0095] FIGS. 3-17 depict one embodiment of an intraocular lens
system 100 which is configured for implantation into the capsular
bag 58 in place of the natural lens 56, and is further configured
to change the refractive properties of the eye in response to the
eye's natural process of accommodation. With reference to FIG. 3, a
set of axes is included to illustrate the sense of directional
terminology which will be used herein to describe various features
of the lens system 100. The terms "anterior" and "posterior" refer
to the depicted directions on the optical axis of the lens 100
shown in FIG. 3. When the lens 100 is implanted in an eye, the
anterior direction extends toward the cornea and the posterior
direction extends toward the retina, with the optical axis of the
lens substantially coincident with the optical axis of the eye
shown in FIGS. 1 and 2. The terms "left" and "right" refer to the
directions shown on the lateral axis, which is orthogonal to the
optical axis. In addition, the terms "upper" and "lower" refer to
the directions depicted on the transverse axis which is orthogonal
to both of the optical axis and the lateral axis.
[0096] This system of axes is depicted purely to facilitate
description herein; thus, it is not intended to limit the possible
orientations which the lens system 100 may assume during use. For
example, the lens system 100 may rotate about, or may be displaced
along, the optical axis during use without detracting from the
performance of the lens. It is clear that, should the lens system
100 be so rotated about the optical axis, the transverse axis may
no longer have an upper-lower orientation and the lateral axis may
no longer have a left-right orientation, but the lens system 100
will continue to function as it would when oriented as depicted in
FIG. 3. Accordingly, when the terms "upper," "lower," "left" or
"right" are used in describing features of the lens system 100,
such use should not be understood to require the described feature
to occupy the indicated position at any or all times during use of
the lens system 100. Similarly, such use should not be understood
to require the lens system 100 to maintain the indicated
orientation at any or all times during use.
[0097] As best seen in FIG. 4, the lens system 100 has an anterior
portion 102 which is anterior or forward of the line A-A (which
represents a plane substantially orthogonal to the optical axis and
intersecting first and second apices 112, 116) and a posterior
portion 104 which is posterior or rearward of the line A-A. The
anterior portion 102 comprises an anterior viewing element 106 and
an anterior biasing element 108. The anterior biasing element 108
in turn comprises a first anterior translation member 110 which
extends from the anterior viewing element 106 to the first apex 112
and a second anterior translation member 114 which extends from the
anterior viewing element 106 to the second apex 116. In the
illustrated embodiment the first anterior translation member 110
comprises a right arm 110a and a left arm 110b (see FIG. 3). In
addition, the depicted second anterior translation member 114
comprises a right arm 114a and a left arm 114b. However, in other
embodiments either or both of the first and second anterior
translation members 110, 114 may comprise a single arm or member,
or more than two arms or members.
[0098] As best seen in FIGS. 4, 5 and 7, the posterior portion 104
includes a posterior viewing element 118 and a posterior biasing
element 120. The posterior biasing element 120 includes a first
posterior translation member 122 extending from the posterior
viewing element 118 to the first apex 112 and a second posterior
translation member 124 extending from the posterior viewing element
118 to the second apex 116. In the illustrated embodiment, the
first posterior translation member comprises a right arm 122a and a
left arm 122b. Likewise, the depicted second posterior translation
member 124 comprises a right arm 124a and a left arm 124b. However,
in other embodiments either or both of the first and second
posterior translation members 122, 124 may comprise a single arm or
member, or more than two arms or members.
[0099] In the embodiment shown in FIG. 4, the anterior biasing
element 108 and the posterior biasing element are configured
symmetrically with respect to the plane A-A as the lens system 100
is viewed from the side. As used herein to describe the biasing
elements 108, 120, "symmetric" or "symmetrically" means that, as
the lens system 100 is viewed from the side, the first anterior
translation member 110 and the first posterior translation member
122 extend from the first apex 112 at substantially equal first
anterior and posterior biasing angles .theta..sub.1, .eta..sub.2
with respect to the line A-A (which, again, represents the edge of
a plane which is substantially orthogonal to the optical axis and
intersects the first and second apices 112, 116) and/or that the
second anterior translation member 114 and the second posterior
translation member 124 extend from the second apex 116 at
substantially equal second anterior and posterior biasing angles
.theta..sub.3, .theta..sub.4 with respect to the line A-A.
Alternative or asymmetric configurations of the biasing elements
are possible, as will be discussed in further detail below. It
should be further noted that a symmetric configuration of the
biasing elements 108, 120 does not dictate symmetric positioning of
the viewing elements with respect to the line A-A; in the
embodiment shown in FIG. 4 the anterior viewing element 106 is
closer to the line A-A than is the posterior viewing element.
[0100] Preferably, both the anterior viewing element 106 and the
posterior viewing element 118 comprise an optic or lens having
refractive power. (As used herein, the term "refractive" or
"refractive power" shall include "diffractive" or "diffractive
power".) The preferred power ranges for the optics are discussed in
detail below. In alternative embodiments one or both of the
anterior and posterior viewing elements 106, 118 may comprise an
optic with a surrounding or partially surrounding perimeter frame
member or members, with some or all of the biasing
elements/translation members attached to the frame member(s). As a
further alternative, one of the viewing elements 106, 118 may
comprise a perimeter frame with an open/empty central portion or
void located on the optical axis (see FIG. 20 and discussion
below), or a perimeter frame member or members with a zero-power
lens or transparent member therein. In still further variations,
one of the viewing elements 106, 118 may comprise only a zero-power
lens or transparent member.
[0101] In a presently preferred embodiment, a retention portion 126
is coupled to the anterior portion 102, preferably at the anterior
viewing element 106. The retention portion 126 preferably includes
a first retention member 128 and a second retention member 130,
although in alternative embodiments the retention portion 126 may
be omitted altogether, or may comprise only one retention member or
more than two retention members. The first retention member 128 is
coupled to the anterior viewing element 106 at a fixed end 128a and
also includes a free end 128b opposite the fixed end 128a.
Likewise, the second retention member 130 includes a fixed end 130a
and a free end 130b. The retention members 128, 130 are illustrated
as being coupled to the anterior viewing element 106 at the upper
and lower edges thereof; however, the retention members 128, 130
may alternatively be attached to the anterior viewing element 106
at other suitable edge locations.
[0102] In the preferred embodiment, the posterior portion 104
includes a distending portion 132, preferably attached to the
posterior viewing element 118. The preferred distending portion 132
includes a first distending member 134 which in turn includes a
fixed end 134a, a free end 134b opposite the fixed end 134a and
preferably also includes an opening 134c formed therein. The
preferred distending portion 132 also comprises a second distending
member 136 with a fixed end 136a, a free end 136b and preferably an
opening 136c formed therein. In alternative embodiments, the
distending portion 132 may be omitted altogether, or may comprise a
single distending member or more than two distending members. To
optimize their effectiveness, the preferred location for the
distending members 134, 136 is 90 degrees away (about the optical
axis) from the apices 112, 116 on the posterior portion 104. Where
the biasing elements form more than two apices (or where two apices
are not spaced 180 degrees apart about the optical axis), one or
more distending members may be positioned angularly midway between
the apices about the optical axis. Alternatively, the distending
member(s) may occupy other suitable positions relative to the
apices (besides the "angularly midway" positions disclosed above);
as further alternatives, the distending member(s) may be located on
the anterior portion 102 of the lens system 100, or even on the
apices themselves. The functions of the retention portion 126 and
the distending portion 132 will be described in greater detail
below.
III. The Lens System: Function/Optics
[0103] The anterior and posterior biasing elements 108, 120
function in a springlike manner to permit the anterior viewing
element 106 and posterior viewing element 118 to move relative to
each other generally along the optical axis. The biasing elements
108, 120 bias the viewing elements 106, 118 apart so that the
elements 106, 108 separate to the accommodated position or
accommodated state shown in FIG. 4. Thus, in the absence of any
external forces, the viewing elements are at their maximum
separation along the optical axis. The viewing elements 106, 118 of
the lens system 100 may be moved toward each other, in response to
a ciliary muscle force of up to 2 grams, to provide an
unaccommodated position by applying appropriate forces upon the
anterior and posterior portions 102, 104 and/or the apices 112,
116.
[0104] When the lens system 100 is implanted in the capsular bag 58
(FIGS. 16-17) the above described biasing forces cause the lens
system 100 to expand along the optical axis so as to interact with
both the posterior and anterior aspects of the capsular bag. Such
interaction occurs throughout the entire range of motion of the
ciliary muscle 60. At one extreme the ciliary muscle is relaxed and
the zonules 62 pull the capsular bag 58 radially so as to cause the
bag to become more disk shaped. The anterior and posterior sides of
the bag, in turn, apply force to the anterior and posterior
portions 102, 104 of the lens system 100, thereby forcing the
viewing elements 106, 118 toward each other into the accommodated
position. At the other extreme, the ciliary muscle contracts and
the zonules 62 move inwardly to provide slack in the capsular bag
58 and allow the bag to become more football-shaped. The slack in
the bag is taken up by the lens system due to the biasing-apart of
the anterior and posterior viewing elements 106, 118. As the radial
tension in the bag is reduced, the viewing elements 106, 118 move
away from each other into an accommodated position. Thus, the
distance between the viewing elements 106, 118 depends on the
degree of contraction or relaxation of the ciliary muscle 60. As
the distance between the anterior and posterior viewing elements
106, 118 is varied, the focal length of the lens system 100 changes
accordingly. Thus, when the lens system 100 is implanted into the
capsular bag (see FIGS. 16-17) the lens system 100 operates in
conjunction with the natural accommodation processes of the eye to
move between the accommodated (FIG. 16) and unaccommodated (FIG.
17) states in the same manner as would a healthy "natural" lens.
Preferably, the lens system 100 can move between the accommodated
and unaccommodated states in less than about one second.
[0105] The entire lens system 100, other than the optic(s), thus
comprises an articulated frame whose functions include holding the
optic(s) in position within the capsular bag and guiding and
causing movement of the optic(s) between the accommodated and
unaccommodated positions.
[0106] Advantageously, the entire lens system 100 may comprise a
single piece of material, i.e. one that is formed without need to
assemble two or more components by gluing, heat bonding, the use of
fasteners or interlocking elements, etc. This characteristic
increases the reliability of the lens system 100 by improving its
resistance to material fatigue effects which can arise as the lens
system experiences millions of accommodation cycles throughout its
service life. It will be readily appreciated that the molding
process and mold tooling discussed herein, lend themselves to the
molding of lens systems 100 that comprise a single piece of
material. However, any other suitable technique may be employed to
manufacture single-piece lens systems.
[0107] In those embodiments where the optic(s) are installed into
annular or other perimeter frame member(s) (see discussion below),
the articulated frame may comprise a single piece of material, to
obtain the performance advantages discussed above. It is believed
that the assembly of the optic(s) to the articulated frame will not
substantially detract from the achievement of these advantages.
[0108] The lens system 100 has sufficient dynamic range that the
anterior and posterior viewing elements 106, 118 move about 0.5-4
mm, preferably about 1-3 mm, more preferably about 1-2 mm, and most
preferably about 1.5 mm closer together when the lens system 100
moves from the accommodated state to the unaccommodated state. In
other words the separation distance X (see FIGS. 9-10, 14-15)
between the anterior and posterior viewing elements 106, 118, which
distance may for present purposes be defined as the distance along
the optical axis (or a parallel axis) between a point of axial
intersection with the posterior face of the anterior viewing
element 106 and a point of axial intersection with the anterior
face of the posterior viewing element 118, decreases by the
amount(s) disclosed above upon movement of the lens system 100 to
the unaccommodated state. Simultaneously, in the preferred mode the
total system thickness Y decreases from about 3.0-4.0 mm in the
accommodated state to about 1.5-2.5 mm in the unaccommodated
state.
[0109] As may be best seen in FIG. 6, the first anterior
translation member 110 connects to the anterior viewing element 106
via connection of the left and right arms 110a, 110b to first and
second transition members 138, 140 at attachment locations 142,
144. The second anterior translation member 114 connects to the
anterior viewing element 106 via connection of left and right arms
114a, 114b to the first and second transition members 138, 140 at
attachment locations 146, 148. This is a presently preferred
arrangement for the first and second anterior translation members
110, 114; alternatively, the first and second anterior translation
members 110, 114 could be connected directly to the anterior
viewing element 106, as is the case with the connection of the
first and second posterior translation members 122, 124 to the
posterior viewing element 118.
[0110] However the connection is established between the first and
second anterior translation members 110, 114 and the anterior
viewing element 106, it is preferred that the attachment locations
142, 144 corresponding to the first anterior translation member 110
be farther away from the first apex 112 than is the closest edge or
the periphery of the anterior viewing element 106. This
configuration increases the effective length of the first anterior
translation member 110/arms 110a, 110b, in comparison to a direct
or straight attachment between the apex 112 and the nearest/top
edge of the anterior viewing element 106. For the same reasons, it
is preferred that the attachment locations 146, 148 associated with
the second anterior translation member 114 be farther away from the
second apex 116 than is the closest/bottom edge of the anterior
viewing element 106.
[0111] As best seen in FIG. 7, the first posterior translation
member 122 is preferably connected directly to the posterior
viewing element 118 via attachment of the left and right arms 122a,
122b to the element 118 at attachment points 150, 152. Likewise,
the second posterior translation member 124 is preferably directly
connected to the posterior viewing element 118 via connection of
the left and right arms 124a, 124b to the element 118 at attachment
points 154, 156, respectively. In alternative embodiments, the
first and second posterior translation members 124, 122 can be
connected to the posterior viewing element via intervening members
as is done with the anterior viewing element 106. No matter how
these connections are made, it is preferred that the attachment
locations 150, 152 be spaced further away from the first apex 112
than is the nearest edge or the periphery of the posterior viewing
element 118. Similarly, it is preferred that the attachment
locations 154, 156 be spaced further away from the second apex 116
than is the closest edge of the posterior viewing element 118.
[0112] By increasing the effective length of some or all of the
translation members 110, 114, 122, 124 (and that of the arms 110a,
110b, 114a, 114b, 122a, 122b, 124a, 124b where such structure is
employed), the preferred configuration of the attachment locations
142, 144, 146, 148, 150, 152, 154, 156 relative to the first and
second apices 112, 116 enables the anterior and/or posterior
viewing elements 106, 118 to move with respect to one another a
greater distance along the optical axis, for a given angular
displacement of the anterior and/or posterior translation members.
This arrangement thus facilitates a more responsive spring system
for the lens system 100 and minimizes material fatigue effects
associated with prolonged exposure to repeated flexing.
[0113] In the illustrated embodiment, the attachment location 142
of the first anterior translation member 110 is spaced from the
corresponding attachment location 146 of the second anterior
translation member 114 along the periphery of the anterior viewing
element, and the same relationship exists between the other pairs
of attachment locations 144, 148; 150, 154; and 152, 156. This
arrangement advantageously broadens the support base for the
anterior and posterior viewing elements 106, 118 and prevents them
from twisting about an axis parallel to the lateral axis, as the
viewing elements move between the accommodated and unaccommodated
positions.
[0114] It is also preferred that the attachment locations 142, 144
of the first anterior translation member 110 be located equidistant
from the first apex 112, and that the right and left arms 110a,
110b of the member 110 be equal in length. Furthermore, the
arrangement of the attachment locations 146, 148, arms 114a, 114b
and second apex preferably mirrors that recited above regarding the
first anterior translation member 110, while the apices 112, 116
are preferably equidistant from the optical axis and are situated
180 degrees apart. This configuration maintains the anterior
viewing element 106 orthogonal to the optical axis as the viewing
element 106 moves back and forth and the anterior viewing element
flexes.
[0115] For the same reasons, a like combination of equidistance and
equal length is preferred for the first and second posterior
translation members 122, 124 and their constituent arms 122a, 122b,
124a, 124b and attachment points 150, 152, 154, 156, with respect
to the apices 112, 116. However, as shown the arms 122a, 122b,
124a, 124b need not be equal in length to their counterparts 110a,
110b, 114a, 114b in the first and second anterior translation
members 110, 114.
[0116] Where any member or element connects to the periphery of the
anterior or posterior viewing elements 106, 118, the member defines
a connection geometry or attachment area with a connection width W
and a connection thickness T (see FIG. 4 and the example
illustrated therein, of the connection of the second posterior
translation member 124 to the posterior viewing element 118). For
purposes of clarity, the connection width is defined as being
measured along a direction substantially parallel to the periphery
of the viewing element in question, and the connection thickness is
defined as measured along a direction substantially perpendicular
to the periphery of the viewing element. (The periphery itself is
deemed to be oriented generally perpendicular to the optical axis
as shown in FIG. 4.) Preferably, no attachment area employed in the
lens system 100 has a ratio of width to thickness less than 3. It
has been found that such a geometry reduces distortion of the
viewing element/optic due to localized forces. For the same
reasons, it is also preferred that each of the translation members
110, 114, 122, 124 be connected to the periphery of the respective
viewing elements at least two attachment areas, each having the
preferred geometry discussed above.
[0117] FIGS. 17A and 17B show two preferred cross-sectional
configurations which may be used along some or all of the length of
the translation members and/or arms 110a, 110b, 114a, 114b, 122a,
122b, 124a, 124b. The shape is defined by a relatively broad and
flat or slightly curved outer surface 182. It is intended that when
in use the outer surface faces away from the interior of the lens
system and/or toward the capsular bag 58. The remaining surfaces,
proportions and dimensions making up the cross-sectional shape can
vary widely but may advantageously be selected to facilitate
manufacture of the lens system 100 via molding or casting
techniques while minimizing stresses in the arms during use of the
lens system.
[0118] FIGS. 17C-17L depict a number of alternative cross-sectional
configurations which are suitable for the translation members
and/or arms 110a, 110b, 114a, 114b, 122a, 122b, 124a, 124b. As
shown, a wide variety of cross-sectional shapes may be used, but
preferably any shape includes the relatively broad and flat or
slightly curved outer surface 182.
[0119] It is further contemplated that the dimensions, shapes,
and/or proportions of the cross-sectional configuration of the
translation members and/or arms 110a, 110b, 114a, 114b, 122a, 122b,
124a, 124b may vary along the length of the members/arms. This may
be done in order to, for example, add strength to high-stress
regions of the arms, fine-tune their spring characteristics, add
rigidity or flexibility, etc.
[0120] As discussed above, each of the anterior viewing element 106
and the posterior viewing element 118 preferably comprises an optic
having refractive power. In one preferred embodiment, the anterior
viewing element 106 comprises a biconvex lens having positive
refractive power and the posterior viewing element 118 comprises a
convexo-concave lens having negative refractive power. The anterior
viewing element 106 may comprise a lens having a positive power
advantageously less than 55 diopters, preferably less than 40
diopters, more preferably less than 35 diopters, and most
preferably less than 30 diopters. The posterior viewing element 118
may comprise a lens having a power which is advantageously between
-25 and 0 diopters, and preferably between -25 and -15 diopters. In
other embodiments, the posterior viewing element 118 comprises a
lens having a power which is between -15 and 0 diopters, preferably
between -13 and -2 diopters, and most preferably between -10 and -5
diopters. Advantageously, the total power of the optic(s) employed
in the lens system 100 is about 5-35 diopters; preferably, the
total power is about 10-30 diopters; most preferably, the total
power is about 15-25 diopters. (As used herein, the term "diopter"
refers to lens or system power as measured when the lens system 100
has been implanted in the human eye in the usual manner.) It should
be noted that if materials having a high index of refraction (e.g.,
higher than that of silicone) are used, the optics may be made
thinner which facilitates a wider range of motion for the optics.
This in turn allows the use of lower-power optics than those
specified above. In addition, higher-index materials allow the
manufacture of a higher-power lens for a given lens thickness and
thereby reduce the range of motion needed to achieve a given range
of accommodation.
[0121] Some lens powers and radii of curvature presently preferred
for use with an embodiment of the lens system 100 with optic(s)
having a refractive index of about 1.432 are as follows: a +31
diopter, biconvex lens with an anterior radius of curvature of
5.944 mm and a posterior radius of curvature of 5.944 mm; a +28
diopter, biconvex lens with an anterior radius of curvature of
5.656 mm and a posterior radius of curvature of 7.788 mm; a +24
diopter, biconvex lens with an anterior radius of curvature of
6.961 mm and a posterior radius of curvature of 8.5 mm; a -10
diopter, biconcave lens with an anterior radius of curvature of
18.765 mm and a posterior radius of curvature of 18.765 mm; a -8
diopter, concavo-convex lens with an anterior radius of curvature
of between 9 mm and 9.534 mm and a posterior radius of curvature of
40 mm; and a -5 diopter, concavo-convex lens with an anterior
radius of curvature of between 9 mm and 9.534 mm and a posterior
radius of curvature of 20 mm. In one embodiment, the anterior
viewing element comprises the +31 diopter lens described above and
the posterior viewing element comprises the -10 diopter lens
described above. In another embodiment, the anterior viewing
element comprises the +28 diopter lens described above and the
posterior viewing element comprises the -8 diopter lens described
above. In another embodiment, the anterior viewing element
comprises the +24 diopter lens described above and the posterior
viewing element comprises the -5 diopter lens described above.
[0122] The combinations of lens powers and radii of curvature
specified herein advantageously minimize image magnification.
However, other designs and radii of curvature provide modified
magnification when desirable.
[0123] The lenses of the anterior viewing element 106 and the
posterior viewing element 118 are relatively moveable as discussed
above; advantageously, this movement is sufficient to produce an
accommodation of at least one diopter, preferably at least two
diopters and most preferably at least three diopters. In other
words, the movement of the optics relative to each other and/or to
the cornea is sufficient to create a difference between (i) the
refractive power of the user's eye in the accommodated state and
(ii) the refractive power of the user's eye in the unaccommodated
state, having a magnitude expressed in diopters as specified above.
Where the lens system 100 has a single optic, the movement of the
optic relative to the cornea is sufficient to create a difference
in focal power as specified above.
[0124] Advantageously, the lens system 100 can be customized for an
individual patient's needs by shaping or adjusting only one of the
four lens faces, and thereby altering the overall optical
characteristics of the system 100. This in turn facilitates easy
manufacture and maintenance of an inventory of lens systems with
lens powers which will fit a large population of patients, without
necessitating complex adjustment procedures at the time of
implantation. It is contemplated that all of the lens systems in
the inventory have a standard combination of lens powers, and that
a system is fitted to a particular patient by simply shaping only a
designated "variable" lens face. This custom-shaping procedure can
be performed to-order at a central manufacturing facility or
laboratory, or by a physician consulting with an individual
patient. In one embodiment, the anterior face of the anterior
viewing element is the designated sole variable lens face. In
another embodiment, the anterior face of the posterior viewing
element is the only variable face. However, any of the lens faces
is suitable for such designation. The result is minimal inventory
burden with respect to lens power (all of the lens systems in stock
have the same lens powers) without requiring complex adjustment for
individual patients (only one of the four lens faces is adjusted in
the fitting process).
IV. The Lens System: Alternative Embodiments
[0125] FIG. 17M depicts another embodiment of the lens system 100
in which the anterior viewing element 106 comprises an optic with a
smaller diameter than the posterior viewing element 118, which
comprises an optic with a peripheral positive-lens portion 170
surrounding a central negative portion 172. This arrangement
enables the user of the lens system 100 to focus on objects at
infinity, by allowing the (generally parallel) light rays incident
upon the eye from an object at infinity to bypass the anterior
viewing element 106. The peripheral positive-lens portion 170 of
the posterior viewing element 118 can then function alone in
refracting the light rays, providing the user with focused vision
at infinity (in addition to the range of visual distances
facilitated by the anterior and posterior viewing elements acting
in concert). In another embodiment, the anterior viewing element
106 comprises an optic having a diameter of approximately 3
millimeters or less. In yet another embodiment, the anterior
viewing element 106 comprises an optic having a diameter of
approximately 3 millimeters or less and a refractive power of less
than 55 diopters, more preferably less than 30 diopters. In still
another embodiment, the peripheral positive-lens portion 170 has a
refractive power of about 20 diopters.
[0126] FIG. 17N shows an alternative arrangement in which, the
anterior viewing element 106 comprises an optic having a central
portion 176 with refractive power, and a surrounding peripheral
region 174 having a refractive power of substantially zero, wherein
the central region 176 has a diameter smaller than the optic of the
posterior viewing element 118, and preferably has a diameter of
less than about 3 millimeters. This embodiment also allows some
incident light rays to pass the anterior viewing element (though
the zero-power peripheral region 174) without refraction, allowing
the peripheral positive-lens portion 170 posterior viewing element
118 to function alone as described above.
[0127] FIGS. 18 and 19 depict another embodiment 250 of the
intraocular lens. It is contemplated that, except as noted below,
this embodiment 250 is largely similar to the embodiment disclosed
in FIGS. 3-17. The lens 250 features an anterior biasing element
108 and posterior biasing element 120 which are arranged
asymmetrically as the lens system 100 is viewed from the side. As
used herein to describe the biasing elements 108, 120, "asymmetric"
or "asymmetrically" means that, as the lens system 100 is viewed
from the side, the first anterior translation member 110 and the
first posterior translation member 122 extend from the first apex
112 at unequal first anterior and posterior biasing angles
.delta..sub.1, .delta..sub.2 with respect to the line B-B (which
represents the edge of a plane which is substantially orthogonal to
the optical axis and intersects the first and second apices 112,
116) and/or that the second anterior translation member 114 and the
second posterior translation member 124 extend from the second apex
116 at substantially equal second anterior and posterior biasing
angles .delta..sub.3, .delta..sub.4 with respect to the line
B-B.
[0128] In the embodiment shown in FIGS. 18-19, the first and second
anterior biasing angles .delta..sub.1, .delta..sub.3 are greater
than the corresponding first and second posterior biasing angles
.delta..sub.2, .delta..sub.4. This arrangement advantageously
maintains the posterior viewing element 118 and apices 112, 116 in
a substantially stationary position. Consequently, the moving mass
of the lens system 250 is reduced, and the anterior viewing element
106 can move more quickly over a wider range along the optical axis
under a given motive force. (Note that even where the posterior
biasing element 120 and its constituent first and second posterior
translation members 122, 124 are substantially immobile, they are
nonetheless "biasing elements" and "translation members" as those
terms are used herein.) In another embodiment, the anterior biasing
element 108 and posterior biasing element 120 are arranged
asymmetrically in the opposite direction, i.e. such that the first
and second anterior biasing angles .delta..sub.1, .delta..sub.3 are
smaller than the corresponding first and second posterior biasing
angles .delta..sub.2, .delta..sub.4. This arrangement also provides
for a wider range of relative movement of the viewing elements, in
comparison to a "symmetric" system.
[0129] It should be further noted that the viewing elements 106,
118 shown in FIGS. 18-19 are asymmetrically positioned in that the
posterior viewing element 118 is closer to the line B-B than is the
anterior viewing element 106. It has been found that this
configuration yields desirable performance characteristics
irrespective of the configuration of the biasing elements 108, 120.
In alternative embodiments, the viewing elements 106, 118 may be
positioned symmetrically with respect to the line B-B, or they may
be positioned asymmetrically with the anterior viewing element 106
closer to the line B-B than the posterior viewing element 118 (see
FIG. 4 wherein the line in question is denoted A-A). Furthermore,
the symmetry or asymmetry of the biasing elements and viewing
elements can be selected independently of each other.
[0130] FIG. 20 shows another embodiment 350 of an intraocular lens
in which the posterior viewing element 118 comprises an annular
frame member defining a void therein, while the anterior viewing
element 106 comprises an optic having refractive power.
Alternatively, the posterior viewing element 118 could comprise a
zero power lens or a simple transparent member. Likewise, in
another embodiment the anterior viewing element 106 could comprise
an annular frame member with a void therein or a simple zero power
lens or transparent member, with the posterior viewing element 118
comprising an optic having refractive power. As a further
alternative, one or both of the anterior and posterior viewing
elements 106, 118 may comprise an annular or other perimeter frame
member which can receive a removable optic (or a "one-time install"
optic) with an interference type fit and/or subsequent adhesive or
welding connections. Such a configuration facilitates assembly
and/or fine-tuning of the lens system during an implantation
procedure, as will be discussed in further detail below.
V. The Lens System: Additional Features
[0131] FIG. 21 depicts the function of the distending portion 132
in greater detail. The lens system 100 is shown situated in the
capsular bag 58 in the customary manner with the anterior viewing
element 106 and posterior viewing element 118 arranged along the
optical axis. The capsular bag 58 is shown with a generally
circular anterior opening 66 which may often be cut into the
capsular bag during installation of the lens system 100. The first
and second distending members 134, 136 of the distending portion
132 distend the capsular bag 58 so that intimate contact is created
between the posterior face of the posterior viewing element and/or
the posterior biasing element 120. In addition, intimate contact is
facilitated between the anterior face of the anterior viewing
element 106 and/or anterior biasing element 108. The distending
members 134, 136 thus remove any slack from the capsular bag 58 and
ensure optimum force coupling between the bag 58 and the lens
system 100 as the bag 58 is alternately stretched and released by
the action of the ciliary muscle.
[0132] Furthermore, the distending members 134, 136 reshape the
capsular bag 58 into a taller, thinner configuration along its
range of accommodation to provide a wider range of relative motion
of the viewing elements 106, 118. When the capsular bag 58 is in
the unaccommodated state, the distending members 134, 136 force the
capsular bag into a thinner configuration (as measured along the
optical axis) in comparison to the unaccommodated configuration of
the capsular bag 58 with the natural lens in place. Preferably, the
distending members 134, 136 cause the capsular bag 58 to taken on a
shape in the unaccommodated state which is about 1.0-2.0 mm
thinner, more preferably about 1.5 mm thinner, along the optical
axis than it is with the natural lens in place and in the
unaccommodated state.
[0133] With such a thin "starting point" provided by the distending
members 134, 136, the viewing elements 106, 118 of the lens system
can move a greater distance apart, and provide a greater range of
accommodation, without causing undesirable contact between the lens
system and the iris. Accordingly, by reshaping the bag as discussed
above the distending members 134, 136 facilitate a range of
relative motion of the anterior and posterior viewing elements 106,
118 of about 0.5-4 mm, preferably about 1-3 mm, more preferably
about 1-2 mm, and most preferably about 1.5 mm.
[0134] The distending portion 132/distending members 134, 136 are
preferably separate from the anterior and posterior biasing
elements 108, 120; the distending members 134, 136 thus, preferably
play no part in biasing the anterior and posterior viewing elements
106, 118 apart toward the accommodated position. This arrangement
is advantageous because the apices 112, 116 of the biasing elements
108, 120 reach their point of minimum protrusion from the optical
axis (and thus the biasing elements reach their minimum potential
effectiveness for radially distending the capsular bag) when the
lens system 100 is in the accommodated state (see FIG. 16), which
is precisely when the need is greatest for a taut capsular bag so
as to provide immediate response to relaxation of the ciliary
muscles. The preferred distending portion is "static" (as opposed
to the "dynamic" biasing members 108, 120 which move while urging
the viewing elements 106, 118 to the accommodated position or
carrying the viewing elements to the unaccommodated position) in
that its member(s) protrude a substantially constant distance from
the optical axis throughout the range of motion of the viewing
elements 106, 118. Although some degree of flexing may be observed
in the distending members 134, 136, they are most effective when
rigid. Furthermore, the thickness and/or cross-sectional profile of
the distending members 134/136 may be varied over the length of the
members as desired to provide a desired degree of rigidity
thereto.
[0135] The distending portion 132/distending members 132, 134
advantageously reshape the capsular bag 58 by stretching the bag 58
radially away from the optical axis and causing the bag 58 to take
on a thinner, taller shape throughout the range of accommodation by
the eye. This reshaping is believed to facilitate a broad (as
specified above) range of relative motion for the viewing elements
of the lens system 100, with appropriate endpoints (derived from
the total system thicknesses detailed above) to avoid the need for
unacceptably thick optic(s) in the lens system.
[0136] If desired, the distending members 134, 136 may also
function as haptics to stabilize and fixate the orientation of the
lens system 100 within the capsular bag. The openings 134c, 136c of
the preferred distending members 134,136 permit cellular ingrowth
from the capsular bag upon positioning of the lens system 100
therein. Finally, other methodologies, such as a separate capsular
tension ring or the use of adhesives to glue the capsular bag
together in selected regions, may be used instead of or in addition
to the distending portion 132, to reduce "slack" in the capsular
bag.
[0137] A tension ring can also act as a physical barrier to cell
growth on the inner surface of the capsular bag, and thus can
provide additional benefits in limiting posterior capsule
opacification, by preventing cellular growth from advancing
posteriorly on the inner surface of the bag. When implanted, the
tension ring firmly contacts the inner surface of the bag and
defines a circumferential barrier against cell growth on the inner
surface from one side of the barrier to another.
[0138] FIG. 21A shows an alternative configuration of the
distending portion 132, in which the distending members 134, 136
comprise first and second arcuate portions which connect at either
end to the apices 112, 116 to form therewith an integral perimeter
member. In this arrangement it is preferred that the distending
members and apices form an oval with height I smaller than width
J.
[0139] FIG. 21B shows another alternative configuration of the
distending portion 132, in which arcuate rim portions 137
interconnect the apices 112, 116 and the free ends 134b, 136b of
the distending members 134, 136. Thus is formed an integral
perimeter member with generally higher lateral rigidity than the
arrangement depicted in FIG. 21A.
[0140] FIG. 21C shows another alternative configuration of the
distending portion 132, in which the distending members 134, 136
are integrally formed with the first and second posterior
translation members 122, 124. The distending members 134, 136 and
translation members 122, 124 thus form common transition members
139 which connect to the periphery of the posterior viewing element
118.
[0141] FIG. 22 shows the function of the retention portion 126 in
greater detail. It is readily seen that the first and second
retention members 128, 130 facilitate a broad contact base between
the anterior portion of the lens system 100 and the anterior aspect
of the capsular bag 58. By appropriately spacing the first and
second retention members 128, 130, the members prevent extrusion of
the anterior viewing element 106 through the anterior opening 66.
It is also readily seen that where contact occurs between the
anterior aspect of the capsular bag 58 and one or both of the
retention members 128, 130, the retention members also participate
in force coupling between the bag 58 and the lens system 100 as the
bag is stretched and released by the action of the ciliary
muscles.
[0142] As best seen in FIGS. 21 and 22, the anterior portion 102 of
the lens system 100 forms a number of regions of contact with the
capsular bag 58, around the perimeter of the anterior viewing
element 106. In the illustrated embodiment, at least some of these
regions of contact are located on the anteriormost portions of the
anterior biasing element 108, specifically at the transition
members 138, 140, and at the retention members 128, 130. The
transition members and the retention members define spaces
therebetween at the edges of the anterior viewing element 106 to
permit fluid to flow between the interior of the capsular bag 58
and the portions of the eye anterior of the bag 58. In other words,
the anterior portion of the lens system 100 includes at least one
location which is spaced from and out of contact with the capsular
bag 58 to provide a fluid flow channel extending from the region
between the viewing elements 106, 118 to the exterior of the bag
58. Otherwise, if the anterior portion 102 of the lens system 100
seals the anterior opening 66 of the bag 58, the resulting
prevention of fluid flow can cause the aqueous humor in the
capsular bag to stagnate, leading to a clinically adverse event,
and can inhibit the movement of the lens system 100 between the
accommodated and unaccommodated states.
[0143] If desired, one or both of the retention members 128, 130
may have an opening 129 formed therein to permit fluid flow as
discussed above. (See FIG. 21A.)
[0144] The retention members 128, 130 and the transition members
138, 140 also prevent contact between the iris and the anterior
viewing element 106, by separating the anterior opening 66 from the
anterior face of the viewing element 106. In other words, the
retention members 128, 130 and the transition members 138, 140
displace the anterior aspect of the capsular bag 58, including the
anterior opening 66, anteriorly from the anterior viewing element
106, and maintain this separation throughout the range of
accommodation of the lens system. Thus, if contact occurs between
the iris and the lens system-capsular bag assembly, no part of the
lens system will touch the iris, only the capsular bag itself, in
particular those portions of the bag 58 overlying the retention
members 128, 130 and/or the transition members 138, 140. The
retention members 128, 130 and/or the transition members 138, 140
therefore maintain a separation between the iris and the lens
system, which can be clinically adverse if the contacting
portion(s) of the lens system are constructed from silicone.
[0145] As depicted in FIG. 22A, one or more stop members or
separation members 190 may be located where appropriate on the
anterior and/or posterior biasing elements 108, 120 to limit the
convergent motion of the anterior and posterior viewing elements
106, 118, and preferably prevent contact therebetween. As the lens
system 100 moves toward the unaccommodated position, the stop
member(s) located on the anterior biasing element 108 come into
contact with the posterior biasing element 120 (or with additional
stop member(s) located on thereon), and any stop member(s) located
on the posterior biasing element 120 come into contact with the
anterior biasing element 108 (or with additional stop member(s)
located thereon). The stop members 190 thus define a point or state
of maximum convergence (in other words, the unaccommodated state)
of the lens system 100/viewing elements 106, 118. Such definition
advantageously assists in setting one extreme of the range of focal
lengths which the lens system may take on (in those lens systems
which include two or more viewing elements having refractive power)
and/or one extreme of the range of motion of the lens system
100.
[0146] The stop members 190 shown in FIG. 22A are located on the
first and second anterior translation members 110, 114 of the
anterior biasing element 108 and extend posteriorly therefrom. When
the anterior and posterior viewing elements 106, 118 move together,
one or more of the stop members 190 will contact the posterior
translation member(s) 122, 124, thereby preventing further
convergent motion of the viewing elements 106, 118. Of course, in
other embodiments the stop member(s) 190 can be in any suitable
location on the lens system 100.
[0147] FIGS. 44-48 depict another embodiment of the lens system 100
having a number of stop members or separation members 190. In this
embodiment the stop members 190 include posts 190a and tabs 190b,
although it will be apparent that any number or combination of
suitable shapes may be employed for the stop members 190. Each of
the stop members 190 has at least one contact surface 191, one or
more of which abuts an opposing surface of the lens system 100 when
the anterior and posterior viewing elements 106, 118 converge to a
minimum separation distance SD (see FIG. 47). In the embodiment
shown, one or more of the contact surfaces 191 of the posts 190a
are configured to abut an opposing surface defined by a
substantially flat anterior perimeter portion 193 of the posterior
viewing element 118, when the viewing elements 106, 118 are at the
minimum separation distance SD. One or more of the contact surfaces
191 of the tabs 190b are configured to abut opposing surfaces
defined by substantially flat anterior faces 195 of the distending
members 134, 136, only if the viewing elements 106, 118 are urged
together beyond the minimum separation distance SD. This
arrangement permits the tabs 190b to function as secondary stop
members should the posts 190a fail to maintain separation of the
viewing elements.
[0148] In other embodiments all of the contact surfaces 191 of the
posts 190a and tabs 190b may be configured to contact their
respective opposing surfaces when the viewing elements 106, 118 are
at the minimum separation distance SD. In still further
embodiments, the contact surfaces 191 of the tabs 190b may be
configured to contact the opposing surfaces when the viewing
elements 106, 118 are at the minimum separation distance SD and the
contact surfaces 191 of the posts 190a configured to contact the
opposing surfaces only if the viewing elements 106, 118 are urged
together beyond the minimum separation distance SD. In one
embodiment, the minimum separation distance SD is about 0.1-1.0 mm;
in another embodiment the minimum separation distance SD is about
0.5 mm.
[0149] When one of the contact surfaces abuts one of the opposing
surfaces, the two surfaces define a contact area CA (see FIG. 48,
depicting an example of a contact area CA defined when the contact
surface 191 of a post 190a contacts an opposing surface defined by
the perimeter portion 193 of the posterior viewing element 118).
Preferably, the contact surface and opposing surface are shaped to
cooperatively minimize the size of the contact area, to prevent
adhesion between the contact surface and the opposing surface,
which is often a concern when one or both of these surfaces has an
adhesive affinity for the other. In the embodiment shown, this
non-adhesive characteristic is achieved by employing a
substantially hemispherical contact surface 191 and a substantially
flat opposing surface (perimeter portion 193). Of course, other
configurations can be selected for the contact surface(s) 191,
including conical, frustoconical, hemicylindrical, pyramidal, or
other rounded, tapered or pointed shapes. All of these
configurations minimize the contact area CA while permitting the
cross-sectional area CS of the stop member 190 (such as the post
190a depicted) to be made larger than the contact area CA, to
impart sufficient strength to the stop member despite the
relatively small contact area CA. Indeed, when constructing the
contact surface(s) 191 any configuration may be employed which
defines a contact area CA which is smaller than the cross-sectional
area CS of the stop member 190. As further alternatives, the
contact surface(s) 191 may be substantially flat and the opposing
surface(s) may have a shape which defines, upon contact with the
opposing surface, a contact area CA which is smaller than the
cross-sectional area CS of the stop member. Thus, the opposing
surface(s) may have, for example, a hemispherical, conical,
frustoconical, hemicylindrical, pyramidal, or other rounded,
tapered or pointed shape.
[0150] Other design features of the stop members 190 can be
selected to maximize their ability to prevent adhesion of the
contact surface(s) to the corresponding opposing surface(s), or
adhesion to each other of any part of the anterior and posterior
portions 102, 104 of the lens system 100. For example, the contact
and opposing surfaces may be formed from dissimilar materials to
reduce the effect of any self-adhesive materials employed in
forming the lens system 100. In addition the shape and/or material
employed in constructing one or more of the stop members 190 can be
selected to impart a spring-like quality to the stop member(s) in
question, so that when the stop member is loaded in compression as
the viewing elements are urged together at the minimum separation
distance, the stop member tends to exert a resisting spring force,
due to either bending or axial compression (or both) of the stop
member, which in turn derive from the elasticity of the material(s)
from which the stop member is constructed, or the shape of the stop
member, or both. This springlike quality is particularly effective
for inhibiting adhesion of areas of the anterior and posterior
portions 102, 104 other than the contact surface(s) and opposing
surface(s).
[0151] As used herein, the term "adhesion" refers to attachment to
each other of (i) an area of the anterior portion 102 of the lens
system 100 and (ii) a corresponding area of the posterior portion
104 (other than the apices 112, 116), wherein such attachment is
sufficiently strong to prevent, other than momentarily, the
anterior and posterior viewing elements 106, 118 from moving apart
along the optical axis under the biasing force of the anterior
and/or posterior biasing elements 108, 120. If the areas in
question are formed of different materials, adhesion may occur
where at least one of the materials has an adhesive affinity for
the other material. If the areas in question are formed of the same
material, adhesion may occur where the material has an adhesive
affinity for itself
[0152] In the embodiment shown, four posts 190a are positioned near
the perimeter of the anterior viewing element 106, equally
angularly spaced around the optical axis. In addition, two tabs
190b are located on either side of the anterior viewing element,
midway between the apices 112, 116 of the lens system. Naturally,
the number, type and/or position of the stop members 190 can be
varied while preserving the advantageous function of maintaining
separation between the anterior and posterior portions of the lens
system.
[0153] The illustrated embodiment employs stop members 190 which
extend posteriorly from the anterior portion 102 of the lens system
100, so that the contact surfaces 191 are located on the posterior
extremities of the stop members 190 and are configured to abut
opposing surfaces formed on the posterior portion 104 of the lens
system 100. However, it will be appreciated that some or all of the
stop members 190 may extend anteriorly from the posterior portion
104 of the lens system 100, so that their contact surfaces 191 are
located on the anterior extremities of the stop members 190 and are
configured to abut opposing surfaces formed on the anterior portion
102 of the lens system 100.
VI. Mold Tooling
[0154] FIGS. 23-34 depict a mold system 500 which is suitable for
molding the lens system 100 depicted in FIG. 3-17. The mold system
500 generally comprises a first mold 502, a second mold 504 and a
center mold 506. The center mold 506 is adapted to be positioned
between the first mold 502 and the second mold 504 so as to define
a mold space for injection molding or compression molding the lens
system 100. The mold system 500 may be formed from suitable metals,
high-impact-resistant plastics or a combination thereof, and can be
produced by conventional machining techniques such as lathing or
milling, or by laser or electrical-discharge machining. The mold
surfaces can be finished or modified by sand blasting, etching or
other texturing techniques.
[0155] The first mold 502 includes a first mold cavity 508 with a
first anterior mold face 510 surrounded by an annular trough 512
and a first perimeter mold face 514. The first mold 502 also
includes a projection 516 which facilitates easier mating with the
second mold 504.
[0156] The center mold 506 includes a first center mold cavity 518
which cooperates with the first mold cavity 508 to define a mold
space for forming the anterior portion 102 of the lens system 100.
The first center mold cavity 518 includes a central anterior mold
face 520 which, upon placement of the center mold 506 in the first
mold cavity 508, cooperates with the first anterior mold face 510
to define a mold space for the anterior viewing element 106. In so
doing, the first anterior mold face 510 defines the anterior face
of the anterior viewing element 106 and the central anterior mold
face 520 defines the posterior face of the anterior viewing element
106. In fluid communication with the chamber formed by the first
anterior mold face 510 and the central anterior mold face 520 are
lateral channels 522, 524 (best seen in FIG. 31) which form spaces
for molding the first and second transition members 138, 140, along
with the arms 110a, 110b of the first anterior translation member
110 as well as the arms 114a, 114b of the second anterior
translation member 114. The first center mold cavity 518 also
includes retention member cavities 526, 528 which define spaces for
molding the first and second retention members 128, 130 to the
anterior viewing element 106.
[0157] The second mold 504 includes a second mold cavity 530 with a
second posterior mold space 532, a generally cylindrical transition
534 extending therefrom and connecting to a second perimeter mold
face 536. Lateral notches 538, 540 (best seen in FIGS. 26 and 27)
are formed in the second perimeter mold face 536. The second mold
504 also includes an input channel 542 connected to an input
channel opening 544 for introducing material into the mold system
500. Also formed in the second mold 504 is an output channel 546
and an output channel opening 548. A generally cylindrical rim 550
is included for mating with the projection 516 of the first mold
502.
[0158] The center mold 506 includes a second center mold cavity 552
which cooperates with the second mold cavity 530 to define a mold
space for the posterior portion 104 of the lens system 100. The
second center mold cavity 552 includes a central posterior mold
face 554 which, upon placement of the center mold 506 in engagement
with the second mold cavity 530, cooperates with the second
posterior mold face 532 and the transition 534 to define a chamber
for forming the posterior viewing element 118. In fluid
communication with the chamber formed by the central posterior mold
face 554 and the second posterior mold face 532 are lateral
channels 556, 558, 560, 562 which provide a mold space for forming
the arms 122a, 122b of the first posterior translation member 122
and the arms 124a, 124b of the second posterior translation member
124. The second center mold cavity 552 includes lateral projections
564, 566 which coact with the notches 538, 540 formed in the second
mold cavity 530. The chambers formed therebetween are in fluid
communication with the chamber defined by the central posterior
mold face 554 and the second posterior mold face 532 to form the
first and second distending members 134, 136 integrally with the
posterior viewing element 118.
[0159] The center mold 506 includes a first reduced-diameter
portion 568 and a second reduced-diameter portion 570 each of
which, upon assembly of the mold system 500, defines a mold space
for the apices 112, 116 of the lens system 100.
[0160] In use, the mold system 500 is assembled with the center
mold 506 positioned between the first mold 502 and the second mold
504. Once placed in this configuration, the mold system 500 is held
together under force by appropriate techniques, and lens material
is introduced into the mold system 500 via the input channel 542.
The lens material then fills the space defined by the first mold
502, second mold 504, and the center mold 506 to take on the shape
of the finished lens system 100.
[0161] The mold system 500 is then disassembled, and in one
embodiment the lens system 100 is left in position on the center
mold 506 after removal of the first and second molds 502, 504. This
technique has been found to improve the effectiveness of any
polishing/tumbling/deflashing procedures which may be performed
(see further discussion below). Whether or not these or any other
additional process steps are performed, the lens system 100 is
preferably removed from the center mold 506 while maintaining the
interconnection of the various components of the lens system
100.
[0162] In another embodiment, the lens system 100 or a portion
thereof is formed by a casting or liquid-casting procedure in which
one of the first or second molds is first filled with a liquid and
the center mold is placed then into engagement with the
liquid-filled mold. The exposed face of the center mold is then
filled with liquid and the other of the first and second molds is
placed into engagement with the rest of the mold system. The liquid
is allowed or caused to set/cure and a finished casting may then be
removed from the mold system.
[0163] The mold system 500 can advantageously be employed to
produce a lens system 100 as a single, integral unit (in other
words, as a single piece of material). Alternatively, various
portions of the lens system 100 can be separately molded, casted,
machined, etc. and subsequently assembled to create a finished lens
system. Assembly can be performed as a part of centralized
manufacturing operations; alternatively, a physician can perform
some or all of the assembly before or during the implantation
procedure, to select lens powers, biasing members, system sizes,
etc. which are appropriate for a particular patient.
[0164] The center mold 506 is depicted as comprising an integral
unit with first and second center mold cavities 518, 552.
Alternatively, the center mold 506 may have a modular configuration
whereby the first and second mold cavities 518, 552 may be
interchangeable to adapt the center mold 506 for manufacturing a
lens system 100 according to a desired prescription or
specification, or to otherwise change the power(s) of the lenses
made with the mold. In this manner the manufacture of a wide
variety of prescriptions may be facilitated by a set of mold
cavities which can be assembled back-to-back or to opposing sides
of a main mold structure.
[0165] FIGS. 49-53 depict one embodiment of a method for
manufacturing the center mold 506. First, a cylindrical blank 1500
formed from any material (such as Ultem) suitable for use in the
mold tooling, is loaded into a holder 1502 as shown in FIG. 49. The
holder 1502 has a main chamber 1504 which has an inner diameter
substantially similar to that of the blank 1500, a smaller-diameter
secondary chamber 1506 rearward of the main chamber 1504, and a
passage 1508 located rearward of the secondary chamber 1506 and
further defined by an annulus 1510. The holder also includes two or
more holder bores 1512 which facilitate attachment of the holder
1502 to a blocker (discussed in further detail below). The blank is
"blocked" in the holder by filling the secondary chamber 1506 and
passage 1508 with water-soluble wax 1514.
[0166] Once the blank 1500 has been loaded and blocked into the
holder 1502, the holder 1502 is secured to a blocker 1516 by bolts
or pins (not shown) which fit snugly into the holder bores 1512.
The holder bores 1512 align precisely with corresponding blocker
bores 1517, by virtue of a snug fit between the blocker bores 1517
and the bolts/pins. The blocker-holder assembly is then loaded into
a conventional machine tool, such as a lathe and/or a mill, and one
of the first and second center mold cavities 518, 552 (the second
cavity 552 is depicted in FIG. 51) is machined from the exposed
face of the blank 1500 using conventional machining techniques. The
holder 1502 and blank 1500, with the second center mold cavity 552
formed thereon, are then removed from the blocker 1516 as shown in
FIG. 51.
[0167] The main chamber 1504 is then filled with water-soluble wax
1520 forward of the second center mold cavity 552, and the wax 1514
is removed from the secondary chamber 1506 and the passage 1508.
Next the holder 1502 is fixed to the blocker 1516 with the as-yet
unmodified portion of the blank 1500 facing outward. Upon
re-loading the holder-blocker assembly into the machine tool, a
portion of the annulus 1510 is then cut away to facilitate tool
access to the blank 1500. A series of machining operations are then
performed on the blank 1500 until the remaining mold cavity (the
first center mold cavity 518 is depicted in FIG. 53) has been
formed. The completed center mold 506 may then be removed from the
holder 1502.
[0168] The machining technique depicted in FIGS. 49-53 is
advantageous in that it facilitates fabrication of the center mold
506 (with both the first and second center mold cavities 518, 552)
from a single piece of material. While it is possible to machine
the first and second center mold cavities 518, 552 from separate
pieces of material which are subsequently glued together, such
assembly creates a seam in the center mold which can retain
contaminants and introduce those contaminants into the mold when
forming the lens system 100. In addition, the assembly of the
center mold 506 from two halves introduces errors wherein the first
and second center mold cavities 518, 552 may be angularly shifted
with respect to each other about the optical axis, or wherein the
mold cavities 518, 552 are non-concentric (i.e., shifted with
respect to each other in a direction orthogonal to the optical
axis). The method depicted in FIGS. 49-53 eliminates these problems
by retaining the blank 1500 in the holder 1502 throughout the
fabrication process and by enforcing precise axial alignment, via
forced alignment of the bores 1512 with the blocker bores 1517,
when machining of both mold cavities.
[0169] In another embodiment, the center mold 506 is formed by a
molding process rather than by machining. The center mold 506 may
be molded from any of the materials disclosed herein as suitable
for forming the lens system 100 itself, including but not limited
to silicone, acrylics, polymethylmethacrylate (PMMA), block
copolymers of styrene-ethylene-butylene-styrene (C-FLEX) or other
styrene-base copolymers, polyvinyl alcohol (PVA), polyurethanes,
hydrogels or any other moldable polymers or monomers.
[0170] The lens system which is formed when employing the molded
center mold 506 may itself be molded from the same material as the
center mold 506. For example, the center mold 506 may be molded
from silicone, and then the lens system 100 may be molded from
silicone by using the mold system 500 with the molded silicone
center mold 506.
[0171] The center mold 506 can be molded by any suitable
conventional techniques. A polished, optical quality initial mold
set can be used to make center molds which in turn will produce
lens systems with optical quality surfaces on the posterior face of
the anterior optic, and the anterior face of the posterior optic.
Alternatively (or additionally), the molded center mold can be
polished and/or tumbled to produce an optically-accurate center
mold.
[0172] The molded center mold 506 offers several advantages over a
machined center mold. First, it is quicker, cheaper and easier to
produce the center mold in large quantities by molding instead of
machining. This in turn facilitates leaving the lens system in
position on the center mold (see FIG. 54) while the lens system is
tumbled, polished and/or deflashed, without incurring undue
expense. The presence of the center mold between the optics
increases the effectiveness of the tumbling/polishing/deflashing by
increasing the hoop strength of the lens system, so that the energy
of the impacting tumbling beads is not dissipated in macroscopic
deformation of the lens system. Molding also permits softer
materials to be employed in forming the center mold, and a softer
center mold is more resistant to damage from deflashing tools and
processes, resulting in fewer center molds lost to such
process-related damage.
VII. Materials/Surface Treatments
[0173] Preferred materials for forming the lens system 100 include
silicone, acrylics, polymethylmethacrylate (PMMA), block copolymers
of styrene-ethylene-butylene-styrene (C-FLEX) or other styrene-base
copolymers, polyvinyl alcohol (PVA), polyurethanes, hydrogels or
any other suitable polymers or monomers. In addition, any portion
of the lens system 100 other than the optic(s) may be formed from
stainless steel or a shape-memory alloy such as nitinol or any
iron-based shape-memory alloy. Metallic components may be coated
with gold to increase biocompatibility. Where feasible, material of
a lower Shore A hardness such as 15A may be used for the optic(s),
and material of higher hardness such as 35A may be used for the
balance of the lens system 100. Finally, the optic(s) may be formed
from a photosensitive silicone to facilitate post-implantation
power adjustment as taught in U.S. patent application Ser. No.
09/416,044, filed Oct. 8, 1999, titled LENSES CAPABLE OF
POST-FABRICATION POWER MODIFICATION, the entire contents of which
are hereby incorporated by reference herein.
[0174] Methyl-methylacrylate monomers may also be blended with any
of the non-metallic materials discussed above, to increase the
lubricity of the resulting lens system (making the lens system
easier to fold or roll for insertion, as discussed further below).
The addition of methyl-methylacrylate monomers also increases the
strength and transparency of the lens system.
[0175] The optics and/or the balance of the lens system 100 can
also be formed from layers of differing materials. The layers may
be arranged in a simple sandwich fashion, or concentrically. In
addition, the layers may include a series of polymer layers, a mix
of polymer and metallic layers, or a mix of polymer and monomer
layers. In particular, a nitinol ribbon core with a surrounding
silicone jacket may be used for any portion of the lens system 100
except for the optics; an acrylic-over-silicone laminate may be
employed for the optics. A layered construction may be obtained by
pressing/bonding two or more layers together, or deposition or
coating processes may be employed.
[0176] Where desired, the anterior optic may be formed from a
material different from that used to form the posterior optic. This
may be done to take advantage of differences between the respective
materials in refractive index, mechanical properties or resistance
to posterior capsule opacification ("PCO"), or to achieve an
appropriate balance of mechanical and optical properties.
Additionally, the use of differing materials can increase
resistance to intra-lenticular opacification ("ILO"). For example,
the material forming the posterior optic may be selected for its
resistance to PCO, and/or for its rigidity (so as to form a
relatively rigid base for the biasing action of the biasing
elements 108, 120, thereby maximizing anterior displacement of the
anterior biasing element). Thus, the posterior optic may be formed
from acrylic; for example, a hydrophobic acrylic. The material
forming the anterior optic may be selected for its high index of
refraction, to keep to a minimum the size and weight of the
anterior optic (and the lens system as a whole), thereby maximizing
the range and speed of motion of the anterior optic in response to
a given biasing force. To achieve these properties the anterior
optic may be formed from silicone; for example,
high-refractive-index silicones (generally, silicones with a
refractive index greater than about 1.43, or silicones with a
refractive index of about 1.46).
[0177] In other embodiments, the anterior optic may be formed from
any suitable material (including those disclosed herein), and the
posterior optic may be formed from any suitable material (including
those disclosed herein) other than the material chosen to form the
anterior optic. In one embodiment the anterior optic is formed from
silicone and the posterior optic is formed from acrylic; in another
embodiment the anterior optic is formed from acrylic and the
posterior optic is formed from silicone.
[0178] The optics may be considered to be formed from different
polymeric materials where no more than about 10 mole percent of
recurring units of the polymer employed in the anterior optic are
the same as the primary recurring units of the polymer employed in
the posterior optic; and/or where no more than about 10 mole
percent of recurring units of the polymer employed in the posterior
optic are the same as the primary recurring units of the polymer
employed in the anterior optic. In general, these conditions are
desirable in order for the two materials to have sufficiently
different material properties. As used herein, a "primary"
recurring unit of a given polymer is the recurring unit which is
present in such polymer in the greatest quantity by mole
percentage.
[0179] In another embodiment, the optics may be considered to be
formed from different polymeric materials where no more than about
10 mole percent of recurring units of the polymer employed in the
anterior optic are of the same type as the primary recurring units
of the polymer employed in the posterior optic; and/or where no
more than about 10 mole percent of the recurring units of the
polymer employed in the posterior optic are of the same type as the
primary recurring units of the polymer employed in the anterior
optic. As used herein, recurring units of the same "type" are in
the same chemical family (i.e., having the same or similar
functionality) or where the backbone of the polymers formed by such
recurring units is essentially the same.
[0180] In one embodiment, portions of the lens system 100 other
than the optic(s) are formed from a shape-memory alloy. This
embodiment takes advantage of the exceptional mechanical properties
of shape-memory alloys and provides fast, consistent, highly
responsive movement of the optic(s) within the capsular bag while
minimizing material fatigue in the lens system 100. In one
embodiment, one or both of the biasing elements 108, 120 are formed
from a shape-memory alloy such as nitinol or any iron-based
shape-memory alloy. Due to the flat stress-strain curve of nitinol,
such biasing elements provide a highly consistent accommodation
force over a wide range of displacement. Furthermore, biasing
elements formed from a shape-memory alloy, especially nitinol,
retain their spring properties when exposed to heat (as occurs upon
implantation into a human eye) while polymeric biasing elements
tend to lose their spring properties, thus detracting from the
responsiveness of the lens system. For similar reasons, it is
advantageous to use shape-memory alloys such as those discussed
above in forming any portion of a conventional (non-accommodating)
intraocular lens, other than the optic.
[0181] Where desired, various coatings are suitable for components
of the lens system 100. A heparin coating may be applied to
appropriate locations on the lens system 100 to prevent
inflammatory cell attachment (ICA) and/or posterior capsule
opacification (PCO); naturally, possible locations for such a
coating include the posterior biasing element 120 and the posterior
face of the posterior viewing element 118. Coatings can also be
applied to the lens system 100 to improve biocompatibility; such
coatings include "active" coatings like P-15 peptides or RGD
peptides, and "passive" coatings such as heparin and other
mucopolysaccharides, collagen, fibronectin and laminin. Other
coatings, including hirudin, teflon, teflon-like coatings, PVDF,
fluorinated polymers, and other coatings which are inert relative
to the capsular bag may be employed to increase lubricity at
locations (such as the optics and distending members) on the lens
system which contact the bag, or Hema or silicone can be used to
impart hydrophilic or hydrophobic properties to the lens system
100.
[0182] It is also desirable subject the lens system 100 and/or the
mold surfaces to a surface passivation process to improve
biocompatibility. This may be done via conventional techniques such
as chemical etching or plasma treatment.
[0183] Furthermore, appropriate surfaces (such as the outer
edges/surfaces of the viewing elements, biasing elements,
distending members, retention members, etc.) of the lens system 100
can be textured or roughened to improve adhesion to the capsular
bag. This may be accomplished by using conventional procedures such
as plasma treatment, etching, dipping, vapor deposition, mold
surface modification, etc. As a further means of preventing
ICA/PCO, a posteriorly-extending perimeter wall (not shown) may be
added to the posterior viewing element 118 so as to surround the
posterior face of the posterior optic. The wall firmly engages the
posterior aspect of the capsular bag and acts as a physical barrier
to the progress of cellular ingrowth occurring on the interior
surface of the capsular bag. Finally, the relatively thick
cross-section of the preferred anterior viewing element 118 (see
FIGS. 9, 10) ensures that it will firmly abut the posterior capsule
with no localized flexing. Thus, with its relatively sharp rim, the
posterior face of the preferred posterior viewing element 118 can
itself serve as a barrier to cellular ingrowth and ICA/PCO. In
order to achieve this effect, the posterior viewing element 118 is
preferably made thicker than conventional intraocular lenses. As an
alternative or supplement to a thick posterior viewing element,
cell growth may be inhibited by forming a pronounced,
posteriorly-extending perimeter rim on the posterior face of the
posterior viewing element 118. Upon implantation of the lens system
100, the rim firmly abuts the inner surface of the capsular bag 58
and acts as a physical barrier to cell growth between the posterior
face of the posterior viewing element 118 and the capsular bag
58.
[0184] The selected material and lens configuration should be able
to withstand secondary operations after molding/casting such as
polishing, cleaning and sterilization processes involving the use
of an autoclave, or ethylene oxide or radiation. After the mold is
opened, the lens should undergo deflashing, polishing and cleaning
operations, which typically involve a chemical or mechanical
process, or a combination thereof. Suitable mechanical processes
include tumbling, shaking and vibration; a tumbling process may
involve the use of a barrel with varying grades of glass beads,
fluids such as alcohol or water and polishing compounds such as
aluminum oxides. Process rates are material dependent; for example,
a tumbling process for silicone should utilize a 6'' diameter
barrel moving at 30-100 RPM. It is contemplated that several
different steps of polishing and cleaning may be employed before
the final surface quality is achieved.
[0185] In one embodiment, the lens system 100 is held in a fixture
to provide increased separation between, and improved process
effect on, the anterior and posterior viewing elements during the
deflashing/polishing/cleaning operations. In another embodiment,
the lens system 100 is everted or turned "inside-out" so that the
inner faces of the viewing elements are better exposed during a
portion of the deflashing/polishing/cleaning. FIG. 34A shows a
number of expansion grooves 192 which may be formed in the
underside of the apices 112, 116 of the lens system 100 to
facilitate eversion of the lens system 100 without damaging or
tearing the apices or the anterior/posterior biasing elements 108,
120. For the same reasons similar expansion grooves may be formed
on the opposite sides (i.e., the outer surfaces) of the apices 112,
116 instead of or in addition to the location of grooves on the
underside.
[0186] A curing process may also be desirable in manufacturing the
lens system 100. If the lens system is produced from silicone
entirely at room temperature, the curing time can be as long as
several days. If the mold is maintained at about 50 degrees C., the
curing time is reduced to about 24 hours; if the mold is preheated
to 100-200 degrees C. the curing time can be as short as about 3-15
minutes. Of course, the time-temperature combinations vary for
other materials.
VIII. Multiple-Piece and Other Embodiments
[0187] FIG. 35 is a schematic view of a two-piece embodiment 600 of
the lens system. In this embodiment the anterior portion 102 and
the posterior portion 104 are formed as separate pieces which are
intended for separate insertion into the capsular bag and
subsequent assembly therein. In one embodiment, each of the
anterior and posterior portions 102, 104 is rolled or folded before
insertion into the capsular bag. (The insertion procedure is
discussed in further detail below.) The anterior portion 102 and
posterior portion 104 are represented schematically as they may
generally comprise any anterior-portion or posterior-portion
structure disclosed herein; for example, they may simply comprise
the lens system 100 shown in FIGS. 3-17, bisected along the
line/plane A-A shown in FIG. 4. The anterior portion 102 and
posterior portion 104 of the two-piece lens system 600 will include
first and second abutments 602, 604 which are intended to be placed
in abutting relation (thus forming the first and second apices of
the lens system) during the assembly procedure. The first and
second abutments 602, 604 may include engagement members (not
shown), such as matching projections and recesses, to facilitate
alignment and assembly of the anterior and posterior portions 102,
104.
[0188] As a further alternative, the anterior and posterior
portions 102, 104 of the lens system 600 may be hingedly connected
at one of the abutments 602, 604 and unconnected at the other, to
allow sequential (but nonetheless partially assembled) insertion of
the portions 102, 104 into the capsular bag. The individual
portions may be separately rolled or folded before insertion. The
two portions 102, 104 are "swung" together and joined at the
unconnected abutment to form the finished lens system after both
portions have been inserted and allowed to unfold/unroll as
needed.
[0189] FIG. 36 depicts schematically another embodiment 700 of a
two-piece lens system. The lens system 700 is desirably similar to
the lens system 600 shown in FIG. 35, except for the formation of
relatively larger, curled abutments 702, 704 which are assembled to
form the apices 112, 116 of the system 700.
[0190] FIGS. 37 and 38 show a further embodiment 800 of the lens
system, in which the anterior and posterior biasing elements 108,
120 comprise integral "band" like members forming, respectively,
the first and second anterior translation members 110, 114 and the
first and second posterior translation members 122, 124. The
biasing elements 108, 120 also form reduced-width portions 802, 804
which meet at the apices of the lens system 800 and provide regions
of high flexibility to facilitate sufficient accommodative
movement. The depicted distending portion 132 includes three pairs
of distending members 134, 136 which have a curved configuration
but nonetheless project generally away from the optical axis.
[0191] FIGS. 38A and 38B depict another embodiment 900 of the lens
system, as implanted in the capsular bag 58. The embodiment shown
in FIGS. 38A and 38B may be similar to any of the embodiments
described above, except that the biasing elements 108, 120 are
dimensioned so that the apices 112, 116 abut the zonules 62 and
ciliary muscles 60 when in the unaccommodated state as seen in FIG.
38A. In addition, the lens system 900 is configured such that it
will remain in the unaccommodated state in the absence of external
forces. Thus, when the ciliary muscles 60 contract, the muscles 60
push the apices 112, 116 closer together, causing the biasing
elements 108, 120 to bow out and the viewing elements 106, 118 to
separate and attain the accommodated state as shown in FIG. 38B.
When the ciliary muscles 60 relax and reduce/eliminate the force
applied to the apices 112, 116 the biasing elements 108, 120 move
the lens system 900 to the unaccommodated state depicted in FIG.
38A.
[0192] FIGS. 38C and 38D depict biasers 1000 which may be used bias
the lens system 100 toward the accommodated or unaccommodated
state, depending on the desired operating characteristics of the
lens system. It is therefore contemplated that the biasers 1000 may
be used with any of the embodiments of the lens system 100
disclosed herein. The bias provided by the biasers 1000 may be
employed instead of, or in addition to, any bias generated by the
biasing elements 108, 120. In one embodiment (see FIG. 38C), the
biasers 1000 may comprise U-shaped spring members having apices
1002 located adjacent the apices 112, 116 of the lens system 100.
In another embodiment (see FIG. 38D), the biasers 1000 may comprise
any suitable longitudinal-compression springs which span the apices
112, 116 and interconnect the anterior and posterior biasing
elements 108, 120. By appropriately selecting the spring constants
and dimensions of the biasers 1000 (in the case of U-shaped
springs, the apex angle and arm length; in the case of
longitudinal-compression springs, their overall length), the
biasers 1000 can impart to the lens system 100 a bias toward the
accommodated or unaccommodated state as desired.
[0193] The biasers 1000 may be formed from any of the materials
disclosed herein as suitable for constructing the lens system 100
itself. The material(s) selected for the biasers 1000 may be the
same as, or different from, the material(s) which are used to form
the remainder of the particular lens system 100 to which the
biasers 1000 are connected. The number of biasers 1000 used in a
particular lens system 100 may be equal to or less than the number
of apices formed by the biasing elements of the lens system
100.
[0194] FIG. 38E depicts a further embodiment of the lens system 100
in which the anterior translation members 110 and the posterior
translation members 120 are paired in a number (in the example
depicted, four) of separate positioners 1400 which are radially
spaced, preferably equally radially spaced, about the optical axis.
In the depicted embodiment, the anterior and posterior translation
members 110, 120 connect directly to the periphery of the viewing
elements 106, 118; however, in other embodiments any of the
connection techniques disclosed herein may be employed. As shown,
the anterior translation members 100 preferably extend anteriorly
from the periphery of the anterior viewing element before bending
and extending posteriorly toward the apex/apices 112. As discussed
above, this configuration is advantageous for promotion of fluid
flow through an opening formed in the anterior aspect of the
capsular bag 58. It has been found that the lens configuration
shown in FIG. 38E is well suited for the folding technique shown in
FIGS. 40A and 40B below. In additional embodiments, the lens system
100 shown in FIG. 38E may incorporate any other suitable features
of the other embodiments of the lens system 100 disclosed herein,
such as but not limited to the distending members and/or retention
members detailed above.
IX. Implantation Methods
[0195] Various techniques may be employed in implanting the various
embodiments of the lens system in the eye of a patient. The
physician can first access the anterior aspect of the capsular bag
58 via any appropriate technique. Next, the physician incises the
anterior of the bag; this may involve making the circular opening
66 shown in FIGS. 21 and 22, or the physician may make a "dumbbell"
shaped incision by forming two small circular incisions or openings
and connecting them with a third, straight-line incision. The
natural lens is then removed from the capsular bag via any of
various known techniques, such as phacoemulsification, cryogenic
and/or radiative methods. To inhibit further cell growth, it is
desirable to remove or kill all remaining epithelial cells. This
can be achieved via cryogenic and/or radiative techniques,
antimetabolites, chemical and osmotic agents. It is also possible
to administer agents such as P15 to limit cell growth by
sequestering the cells.
[0196] In the next step, the physician implants the lens system
into the capsular bag. Where the lens system comprises separate
anterior and posterior portions, the physician first folds or rolls
the posterior portion and places it in the capsular bag through the
anterior opening. After allowing the posterior portion to
unroll/unfold, the physician adjusts the positioning of the
posterior portion until it is within satisfactory limits. Next the
physician rolls/folds and implants the anterior portion in a
similar manner, and aligns and assembles the anterior portion to
the posterior portion as needed, by causing engagement of mating
portions, etc. formed on the anterior and posterior portions.
[0197] Where the lens system comprises anterior and posterior
portions which are partially assembled or partially integral (see
discussion above in the section titled MULTIPLE-PIECE AND OTHER
EMBODIMENTS), the physician employs appropriate implantation
procedures, subsequently folding/rolling and inserting those
portions of the lens system that are separately foldable/rollable.
In one embodiment, the physician first rolls/folds one portion of
the partially assembled lens system and then inserts that portion.
The physician then rolls/folds another portion of the partially
assembled lens system and the inserts that portion. This is
repeated until the entire system is inside the capsular bag,
whereupon the physician completes the assembly of the portions and
aligns the lens system as needed. In another embodiment, the
physician first rolls/folds all of the separately rollable/foldable
portions of the partially assembled lens system and then inserts
the rolled/folded system into the capsular bag. Once the lens
system is in the capsular bag, the physician completes the assembly
of the portions and aligns the lens system as needed.
[0198] It is contemplated that conventional intraocular lens
folding devices, injectors, syringes and/or shooters can be used to
insert any of the lens systems disclosed herein. A preferred
folding/rolling technique is depicted in FIGS. 39A-39B, where the
lens system 100 is shown first in its normal condition (A). The
anterior and posterior viewing elements 106, 118 are manipulated to
place the lens system 100 in a low-profile condition (B), in which
the viewing elements 106, 118 are out of axial alignment and are
preferably situated so that no portion of the anterior viewing
element 106 overlaps any portion of the posterior viewing element
118, as viewed along the optical axis. In the low-profile position
(B), the thickness of the lens system 100 is minimized because the
viewing elements 106, 118 are not "stacked" on top of each other,
but instead have a side-by-side configuration. From the low-profile
condition (B) the viewing elements 106, 118 and/or other portions
of the lens system 100 can be folded or rolled generally about the
transverse axis, or an axis parallel thereto. Alternatively, the
lens system could be folded or rolled about the lateral axis or an
axis parallel thereto. Upon folding/rolling, the lens system 100 is
placed in a standard insertion tool as discussed above and is
inserted into the eye.
[0199] When the lens system 100 is in the low-profile condition
(B), the system may be temporarily held in that condition by the
use of dissolvable sutures, or a simple clip which is detachable or
manufactured from a dissolvable material. The sutures or clip hold
the lens system in the low-profile condition during insertion and
for a desired time after insertion. By temporarily holding the lens
system in the low-profile condition after insertion, the sutures or
clip provide time for fibrin formation on the edges of the lens
system which, after the lens system departs from the low-profile
condition, may advantageously bind the lens system to the inner
surface of the capsular bag.
[0200] The physician next performs any adjustment steps which are
facilitated by the particular lens system being implanted. Where
the lens system is configured to receive the optic(s) in "open"
frame members, the physician first observes/measures/determines the
post-implantation shape taken on by the capsular bag and lens
system in the accommodated and/or unaccommodated states and
select(s) the optics which will provide the proper lens-system
performance in light of the observed shape characteristics and/or
available information on the patient's optical disorder. The
physician then installs the optic(s) in the respective frame
member(s); the installation takes place either in the capsular bag
itself or upon temporary removal of the needed portion(s) of the
lens system from the bag. If any portion is removed, a final
installation and assembly is then performed with the optic(s) in
place in the frame member(s).
[0201] Where the optic(s) is/are formed from an appropriate
photosensitive silicone as discussed above, the physician
illuminates the optic(s) (either anterior or posterior or both)
with an energy source such as a laser until they attain the needed
physical dimensions or refractive index. The physician may perform
an intervening step of observing/measuring/determining the
post-implantation shape taken on by the capsular bag and lens
system in the accommodated and/or unaccommodated states, before
determining any needed changes in the physical dimensions or
refractive index of the optic(s) in question.
[0202] FIG. 40 depicts a technique which may be employed during
lens implantation to create a fluid flow path between the interior
of the capsular bag 58 and the region of the eye anterior of the
capsular bag 58. The physician forms a number of fluid-flow
openings 68 in the anterior aspect of the capsular bag 58, at any
desired location around the anterior opening 66. The fluid-flow
openings 68 ensure that the desired flow path exists, even if a
seal is created between the anterior opening 66 and a viewing
element of the lens system.
[0203] Where an accommodating lens system is implanted, the
openings 68 create a fluid flow path from the region between the
viewing elements of the implanted lens system, and the region of
the eye anterior of the capsular bag 58. However, the technique is
equally useful for use with conventional (non-accommodating)
intraocular lenses.
[0204] FIGS. 40A and 40B illustrate another embodiment of a method
of folding the lens system 100. In this method the anterior viewing
element 106 is rotated approximately 90 degrees about the optical
axis with respect to the posterior viewing element 118. This
rotation may be accomplished by applying rotational force to the
upper edge of the first transition member 138 and the lower edge of
the second transition member 140 (or vice versa), as indicated by
the dots and arrows in FIG. 40A, while holding the posterior
viewing element 118 stationary, preferably by gripping or clamping
the distending members 134, 136. Alternatively, rotational force
may be applied in a similar manner to a right edge of one of the
retention members 128, 130 and to a left edge of the other of the
retention members while holding the posterior viewing element 118
stationary. As still further alternatives, the anterior viewing
element 106 could be held stationary while rotational force is
applied to the posterior viewing element 118, at an upper edge of
one of the distending members 134, 136 and at a lower edge of the
other of the distending members; or both the anterior and posterior
viewing elements 106, 118 could be rotated with respect to each
other.
[0205] Preferably, the viewing elements 106, 118 are spread apart
somewhat as the rotation is applied to the lens system so that the
translation members and apices are drawn into the space between the
viewing elements 106, 118 in response to the rotational Lorcc. Once
the anterior viewing element 106 has been rotated approximately 90
degrees about the optical axis with respect to the posterior
viewing element 118, the lens system 100 takes on the configuration
shown in FIG. 40B, with the retention members 128, 130 generally
radially aligned with the distending members 134, 136 and the
translation members and apices disposed between the viewing
elements 106, 118. This configuration is advantageous for inserting
the lens system 100 into the capsular bag 58 because it reduces the
insertion profile of the lens system 100 while storing a large
amount of potential energy in the translation members. From the
folded configuration the translation members thus exert a high
"rebound" force when the lens system has been inserted to the
capsular bag 58, causing the lens system to overcome any
self-adhesion and spring back to the unfolded configuration shown
in FIG. 40A without need for additional manipulation by the
physician.
[0206] Once the lens system 100 is in the folded configuration
shown in FIG. 40B, it may be further folded and/or inserted into
the capsular bag 58 by any suitable methods presently known in the
art or hereafter developed. For example, as shown in FIG. 40C the
folding method may further comprise inserting the folded lens
system 100 between the prongs 1202, 1204 of a clip 1200, preferably
with the prongs 1202, 1204 oriented to extend along the transition
members 138, 140, or along the retention members 128, 130 and the
distending members 134, 136.
[0207] FIGS. 40D-40F illustrate the use of jaws 1250, 1252 of a
pliers or forceps to fold the lens system 100 as it is held in the
clip 1200. (FIGS. 40D-40F show an end view of the clip-lens system
assembly with the jaws 1250, 1252 shown in section for clarity.) As
shown in FIGS. 40D and 40E, the edges of the jaws 1250, 1252 are
urged against one of the anterior and posterior viewing elements
106, 118 while the jaws 1250, 1252 straddle the prong 1202 of the
clip 1200. The resulting three-point load on the lens system 1200
causes it to fold in half as shown in FIG. 40E. As the lens system
100 approaches the folded configuration shown in FIG. 40F, the jaws
1250, 1252 slide into a pincer orientation with respect to the lens
system 100, characterized by contact between the inner faces 1254,
1256 of the jaws 1250, 1252 and the anterior viewing element 106 or
posterior viewing element 118. With such a pincer orientation
established, the forceps may be used to grip and compress the lens
system with inward-directed pressure and the clip 1200 can be
withdrawn, as shown in FIG. 40F. With the lens system 100 thus
folded, it can be inserted to the capsular bag 58 by any suitable
method presently known in the art or hereafter developed.
[0208] FIG. 40G depicts a folding tool 1300 which may be employed
to fold the lens system 100 as discussed above in connection with
FIGS. 40A and 40B. The tool 1300 includes a base 1302 with brackets
1304 which hold the lens system 100 to the base 1302 by gripping
the distending members 134, 136. Formed within the base 1302 are
arcuate guides 1306. The tool further comprises a rotor 1308 which
in turn comprises a horizontal rod 1310 and integrally formed
vertical rods 1312. The vertical rods 1312 engage the arcuate
guides 1306, both of which have a geometric center on the optical
axis of the lens system 100. The vertical rods 1312 and the arcuate
guides 1306 thus coact to allow the horizontal rod to rotate at
least 90 degrees about the optical axis of the lens system 100. The
horizontal rod 1310 is fixed with respect to the anterior viewing
element 106 of the lens system 100 so as to prevent substantially
no relative angular movement between the rod 1310 and the anterior
viewing element 106 as the rod 1310 (and, in turn, the anterior
viewing element 106) rotates about the optical axis of the lens
system 100. This fixed relationship may be established by adhesives
and/or projections (not shown) which extend downward from the
horizontal rod 1308 and bear against the upper edge of one of the
transition members 138, 140 and against the lower edge of the other
of the transition members as shown in FIG. 40A. As an alternative
or as a supplement to this arrangement, the projections may bear
against the retention members 128, 130 in a similar manner as
discussed above.
[0209] Thus, when the rotor 1308 is advanced through its range of
angular motion about the optical axis of the lens system 100, it
forces the anterior viewing element 106 to rotate in concert
therewith about the optical axis, folding the lens system as
discussed above in connection with FIGS. 40A and 40B. It is further
contemplated that the folding tool 1300 may comprise the lower half
of a package in which the lens system is stored and/or shipped to a
customer, to minimize the labor involved in folding the lens system
at the point of use. Preferably, the lens system is stored in the
tool 1300 in the unfolded configuration, so as to avoid undesirable
deformation of the lens system.
[0210] FIG. 55 is a flow diagram of an exemplary method 1600 of
implanting an accommodating intraocular lens system 100 in a
capsular bag 58 of an eye 50 in accordance with embodiments
described herein. FIGS. 56A-56F schematically illustrate various
configurations of an exemplary intraocular lens system 100 oriented
within the capsular bag 58 in a manner compatible with the method
1600. FIG. 56A is a schematical cross-sectional view of the
intraocular lens system 100 within the capsular bag 58. FIGS.
56B-56F schematically illustrate various configurations of the
opening 66 in the capsular bag 58 as viewed from an anterior
position relative to the capsular bag 58. While the description of
the method 1600 below is made in reference to the lens structures
schematically illustrated by
[0211] FIGS. 56A-56F, other structures are compatible with the
method 1600, including, without limitation, the lens structures
schematically illustrated by FIGS. 3-17, 21, and 22.
[0212] In certain embodiments, in an operational block 1610, the
method 1600 comprises providing the accommodating intraocular lens
system 100 which has an anterior viewing element 106 and a
posterior viewing element 118. In certain embodiments, in an
operational block 1620, the method 1600 further comprises forming
an opening 66 (sometimes referred to as a "capsulorhexis") in an
anterior portion of the capsular bag 58. In certain embodiments, in
an operational block 1630, the method 1600 further comprises
placing the accommodating intraocular lens system 100 within the
capsular bag 58. The intraocular lens system 100 is placed so that
capsular bag 58 overlaps at least a portion of the anterior viewing
element 106.
[0213] In certain embodiments, the anterior viewing element 106 has
a width W.sub.1 in a range between approximately 4.5 millimeters
and approximately 6.5 millimeters. In other embodiments, the
anterior viewing element 106 has a width W.sub.1 in a range between
approximately 5 millimeters and approximately 5.5 millimeters. In
still other embodiments, the anterior viewing element 106 has a
width W.sub.1 approximately equal to 5 millimeters. In certain
embodiments, the anterior viewing element 106 has a refractive
anterior portion having a width or a diameter in a range between
approximately 4 millimeters and approximately 5.5 millimeters.
[0214] Where the anterior viewing element 106 is generally
circular, the width W.sub.1 may comprise a diameter of the anterior
viewing element 106. In certain embodiments, the width W.sub.1 may
comprise the largest dimension of the anterior viewing element 106
along a direction of measurement passing through the center or the
centroid of the anterior viewing element 106, when the viewing
element 106 is viewed as depicted in FIGS. 56B-56F.
[0215] In certain embodiments, forming the opening 66 in the
capsular bag 58 in the operational block 1620 is performed by the
physician as described above. In certain embodiments, the physician
accesses the anterior portion of the capsular bag 58 and incises
the anterior portion of the capsular bag 58 to cut the opening 66
and to remove the natural lens from the capsular bag 58.
[0216] As schematically illustrated by FIG. 56B, in certain
embodiments, the opening 66 is generally circular and has a
diameter or width W.sub.2. As schematically illustrated by FIGS.
56C-56F, in certain embodiments, the opening 66 is generally
non-circular and has a width or diameter W.sub.2 which varies along
various directions of measurement. The openings 66 schematically
illustrated by FIGS. 56C and 56F are generally oval, the opening 66
schematically illustrated by FIG. 56D is generally
"dumbbell-shaped," the opening 66 schematically illustrated by FIG.
56E is generally non-symmetric. In certain embodiments, the width
W.sub.2 may comprise the largest dimension of the opening 66 along
a direction of measurement passing through the center or the
centroid of the opening 66, when the opening 66 is viewed as
depicted in FIGS. 56B-56F.
[0217] In certain embodiments, the width W.sub.2 of the opening 66
is in a range between approximately 0.2 millimeter less than the
width W.sub.1 of the anterior viewing element 106 and approximately
1.5 millimeters less than the width W.sub.1 of the anterior viewing
element 106. In certain embodiments, the width W.sub.2 of the
opening 66 is in a range between approximately 0.4 millimeter and
approximately 0.8 millimeter less than the width W.sub.1 of the
anterior viewing element 106. In certain embodiments, the width
W.sub.1 of the anterior viewing element 106 is approximately 5
millimeters and the width W.sub.2 of the opening 66 is not less
than 4.3 millimeters. In certain embodiments, the width W.sub.1 of
the anterior viewing element 106 is approximately 5 millimeters and
the width W.sub.2 of the opening 66 is not greater than 4.8
millimeters. In certain embodiments, the width W.sub.1 of the
anterior viewing element 106 is approximately 5 millimeters and the
width W.sub.2 of the opening 66 is approximately 4.75
millimeters.
[0218] In certain embodiments, the smallest diameter or width of
the opening 66 along various directions of measurement is referred
to as the minimum width and the largest diameter or width of the
opening 66 along various directions of measurement is referred to
as the maximum width. In certain embodiments, the opening 66 has an
average width between the minimum width and the maximum width. In
certain embodiments, the average width is equal to an average of
the minimum width and the maximum width. In other embodiments, the
average width is equal to an average of a plurality of diameters or
widths of the opening 66 along a plurality of directions. In
certain embodiments having a generally circular opening 66, such as
that schematically illustrated by FIG. 56B, the minimum width of
the opening 66, the maximum width of the opening 66, and the
average width of the opening 66 are equal to one another.
[0219] In certain embodiments, the opening 66 has a minimum width
not less than approximately 4 millimeters and has a maximum width
not greater than approximately 6.0 millimeters. In other
embodiments, the width W.sub.1 of the anterior viewing element 106
is approximately 5 millimeters and the opening 66 has a minimum
width that is not less than 4.3 millimeters. In still other
embodiments, the width W.sub.1 of the anterior viewing element 106
is approximately 5 millimeters and the opening 66 has a maximum
width that is not greater than 4.8 millimeters. In still other
embodiments, the width W.sub.1 of the anterior viewing element 106
is approximately 5 millimeters and the opening 66 has an average
width of approximately 4.75 millimeters.
[0220] In certain embodiments, the operational block 1630 comprises
placing the accommodating intraocular lens system 100 within the
capsular bag 58. The intraocular lens system 100 is placed so that
capsular bag 58 overlaps at least a portion of the anterior viewing
element 106 and defines an overlap region 1700 with a width
.DELTA.W. In certain embodiments, the width .DELTA.W of the overlap
region 1700 is in a range between approximately 0.1 millimeter and
approximately 0.75 millimeter. In certain embodiments, such as
those schematically illustrated by FIGS. 56A-56F, the width AW of
the overlap region 1700 is measured from a first point at the edge
of the anterior viewing element 106 to a corresponding second point
at the edge of the opening 66 of the capsular bag 58. The second
point of certain embodiments is a point at the edge of the opening
66 of the capsular bag 58 which is closest to the first point along
any direction. The second point of other embodiments is a point at
the edge of the opening of the capsular bag 58 which is closest to
the first point along a diameter direction of the anterior viewing
element 106.
[0221] In certain embodiments, the overlap region 1700
advantageously facilitates proper positioning of the intraocular
lens system 100 inside the capsular bag 58 and facilitates proper
functioning of the intraocular lens system 100. In certain
embodiments, the overlap region 1700 decreases the probability of
the incidence of posterior capsular opacification ("PCO") by
pushing the posterior viewing element 118 against the posterior
portion of the capsular bag 58.
[0222] As schematically illustrated by FIG. 56B, in certain
embodiments in which both the anterior viewing element 106 and the
opening 66 are both generally circular and are concentric with one
another, the width AW is substantially constant over the entire
overlap region 1700. For embodiments in which the anterior viewing
element 106 and the opening 66 are both generally circular but are
not concentric, the width AW varies at various portions of the
overlap region 1700.
[0223] As schematically illustrated by FIGS. 56C-56F, in other
embodiments with a generally circular anterior viewing element 106
and a non-circular opening 66, the width AW varies at various
portions of the overlap region 1700. FIGS. 56B-56F schematically
illustrate the opening 66 as being generally centered about the
center of the anterior viewing element 106. In other embodiments,
the opening 66 is offset from the center of the anterior viewing
element 106, thereby providing an additional variation to the width
AW at various portions of the overlap region 1700.
[0224] FIG. 56F schematically illustrates a non-circular opening 66
having a width W.sub.2 which is smaller than the width W.sub.1 of
the anterior viewing element 106 in the overlap region 1700 and a
width W.sub.2 which is larger than the width W.sub.1 outside the
overlap region 1700. In certain such embodiments, the overlap
region 1700 does not completely encircle the opening 66 and the
width AW of the overlap region 1700 is the maximum width of the
overlap region 1700, as indicated by FIG. 56F.
[0225] In certain embodiments, the width AW of the overlap region
1700 is in a range between approximately 0.1 millimeter and
approximately 0.75 millimeter. In other embodiments, the width AW
of the overlap region 1700 is in a range between approximately 0.1
millimeter and approximately 0.5 millimeter. In still other
embodiments, the width AW of the overlap region 1700 is in a range
between approximately 0.2 millimeter and approximately 0.4
millimeter.
[0226] In certain embodiments, the intraocular lens system 100 is
configured to allow fluid flow between a region of the eye 50
anterior to the anterior viewing element 106 and a region posterior
to the anterior viewing element 106. By allowing fluid flow between
the anterior and posterior regions relative to the anterior viewing
element 106, embodiments described herein advantageously prevent
stagnation of the aqueous humor in the capsular bag 58, as
described above. In addition, by allowing fluid flow, embodiments
described herein advantageously prevent inhibition of the movement
of the intraocular lens system 100 between the accommodated and
unaccommodated states, as described above.
[0227] In certain embodiments, the intraocular lens system 100
allows fluid flow by contacting at least a portion of the capsular
bag 58 and spacing the portion of the capsular bag 58 from the
anterior viewing element 106. In certain such embodiments, as
schematically illustrated by FIG. 21, at least a portion of the
anterior basing element 108 (e.g., first transition member 138
and/or second transition members 140) contacts a respective portion
of the capsular bag 58 and spaces it from the anterior viewing
element 106.
[0228] In other such embodiments, as schematically illustrated by
FIG. 22, at least a portion of the retention portion 126 (e.g.,
first retention member 128 and/or second retention member 130)
contacts a respective portion of the capsular bag 58 and spaces it
from the anterior viewing element 106. In certain such embodiments,
the capsular bag 58 extends inward from the retention member
towards the optical axis by no more than 1.25 millimeters. The
retention portion 126 in contact with the capsular bag 58 is
advantageously dimensioned in certain embodiments so that the
capsular bag 58 is spaced from the anterior viewing element 106
while neither the intraocular lens system 100 nor the capsular bag
58 contacts the iris of the eye.
[0229] In certain embodiments, the capsular bag 58 contacts at
least a portion of the anterior viewing element 106 upon insertion
of the intraocular lens system 100 into the capsular bag 58, as
schematically illustrated by FIG. 57. In certain such embodiments,
the width AW of the overlap region 1700 is sufficiently small to
allow the capsular bag 58 to move away from the portion of the
anterior viewing element 106 in response to fluid flow between the
region of the eye anterior to the anterior viewing element 106 and
the region of the eye posterior to the anterior viewing element
106. Thus, the portion of the capsular bag 58 in contact with the
anterior viewing element 106 acts as a movable "flap" which moves
in response to fluid flow. In such embodiments, the width W.sub.1
of the anterior viewing element 106 is sufficiently small to allow
the capsular bag 58 to move away from the portion of the anterior
viewing element 106 in response to the fluid flow between the
anterior region and the posterior region of the eye relative to the
anterior viewing element 106.
[0230] In certain embodiments, the anterior viewing element 106
comprises a plurality of conduits through which fluid can flow
between the region anterior to the anterior viewing element 106 and
the region posterior to the anterior viewing element 106. In this
way, the intraocular lens system 100 allows fluid flow between the
anterior region and the posterior region of the eye relative to the
anterior viewing element 106. In certain such embodiments, the
plurality of conduits comprises a plurality of holes through a
periphery portion of the anterior viewing element 106 in the
overlap region 1700.
[0231] In certain embodiments, while the capsular bag 58 is in
contact with the anterior viewing element 106, circumferential
sealing of the capsular bag 58 to the anterior viewing element 106
is avoided. In certain embodiments, movement of the intraocular
lens system 100 between an accommodating state and a
non-accommodating state results in a hydraulic pumping action which
moves aqueous fluid and inhibits adhesion of the capsular bag 58 to
the anterior viewing element 106. With repeated accommodative
response of certain such embodiments, aqueous fluid is moved in and
out of the capsular bag 58 and this fluid flow inhibits total
capsular block and attachment of the anterior viewing element 106
to the capsular bag 58 completely around the capsularhexis
diameter.
X. Thin Optic Configurations
[0232] In some circumstances it is advantageous to make one or more
of the optics of the lens system relatively thin, in order to
facilitate rolling or folding, or to reduce the overall size or
mass of the lens system. Discussed below are various optic
configurations which facilitate a thinner profile for the optic;
any one of these configurations may be employed as well as any
suitable combination of two or more of the disclosed
configurations.
[0233] One suitable technique is to employ a material having a
relatively high index of refraction to construct one or more of the
optics. In one embodiment, the optic material has an index of
refraction higher than that of silicone. In another embodiment, the
material has an index of refraction higher than about 1.43. In
further embodiments, the optic material has an index of refraction
of about 1.46, 1.49 or 1.55. In still further embodiments, the
optic material has an index of refraction of about 1.43 to 1.55. By
employing a material with a relatively high index of refraction,
the curvature of the optic can be reduced (in other words, the
radius/radii of curvature can be increased) thereby reducing the
thickness of the optic without loss of focal power.
[0234] A thinner optic can also be facilitated by forming one or
more of the surfaces of one or more of the optics as an aspheric
surface, while maintaining the focal power of the optic. As shown
in FIG. 41, an aspheric, convex optic surface 1100 can be formed
with the same radius of curvature (as a comparable-power spherical
surface) at the vertex 1102 of the surface 1100 and a longer radius
of curvature (with a common center point) at its periphery 1104,
creating a thinner optic without sacrificing focal power. This
contrasts with a spherical optic surface 1106, which is thicker at
its vertex 1108 than is the aspheric surface 1102. In one
embodiment, the thickness of the optic is reduced by about 19% at
the vertex relative to a comparable-power spherical optic. It is
contemplated that thinner, aspheric concave optic surfaces may be
used as well. A further advantage of an aspheric optic surface is
that it provides better image quality with fewer aberrations, and
facilitates a thinner optic, than a comparable spherical
surface.
[0235] FIG. 42 depicts a further strategy for providing a thinner
optic 1150. The optic 1150 has a curved (spherical or aspheric)
optic surface 1152 and a flat or planar (or otherwise less curved
than a comparable refractive surface) diffractive optic surface
1154 in place of a second curved surface 1156. The diffractive
optic surface 1154 can comprise any suitable diffraction grating,
including the grooved surface depicted or any other diffractive
surface presently known or hereafter developed, including
holographic optical elements. By appropriately configuring the
diffractive surface 1154 as is well known in the art, the optic
1150 can be made thinner than one having both curved surfaces 1152,
1154, while providing the same focal power. The use of the
diffractive surface 1154 not only facilitates a thinner optic, but
also reduces aberrations in the resulting image.
[0236] A further alternative for facilitating a thin, easy-to-fold
optic is to employ, in place of a biconvex optic of refractive
index greater than aqueous humor (i.e., greater than about 1.336),
a biconcave optic of refractive index less than about 1.336, which
is thinner at the optical axis than the biconvex optic. By
constructing the biconcave optic of material having a refractive
index less than about 1.336, the biconcave optic can be made to
have the same effective focal power, when immersed in aqueous
humor, as a given biconvex optic.
[0237] Still another alternative thin optic, shown in FIG. 43, is a
biconcave optic 1160 of low refactive index (for example, about
1.40 or less or about 1.336 or less) which is clad with first and
second cladding portions 1162, 1164 constructed of higher-index
material (for example, about 1.43 or greater). Such an optic can be
made to have the same effective focal power, when immersed in
aqueous humor, as a thicker biconvex optic.
[0238] As a further alternative, one or more of the surfaces of the
optics may be formed as a multifocal surface, with spherical and/or
aspheric focal regions. A multifocal surface can be made with less
curvature than a comparable-power single-focus surface and thus
allows the optic to be made thinner. The additional foci provide
added power which replaces or exceeds the power that is "lost" when
the surface is reduced in curvature. In one embodiment, the
multifocal optic is constructed as a concentric-ring, refractive
optic. In another embodiment, the multifocal optic is implemented
as a diffractive multifocal optic.
[0239] Although this invention has been disclosed in the context of
certain preferred embodiments and examples, it will be understood
by those skilled in the art that the present invention extends
beyond the specifically disclosed embodiments to other alternative
embodiments and/or uses of the invention and obvious modifications
and equivalents thereof. Thus, it is intended that the scope of the
present invention herein disclosed should not be limited by the
particular disclosed embodiments described above, but should be
determined only by a fair reading of the claims that follow.
* * * * *