High myopia anterior chamber lens with anti-glare mask

A two piece anterior chamber artificial intraocular lens for treating high myopia conditions by implantation in an eye after extracapsular removal of the natural eye lens is disclosed. The two-piece assembly is inserted through a minimum size incision in the eye. The lens includes a lens body or optic and a separate ring-shaped tension frame therefor containing light masking means for inhibiting light rays directed toward the outer edge portions of the lens body from being scattered thereby toward the retina after the assembled lens has been inserted into the eye. The lens body or optic is generally circular and conveniently made of shape retaining plastic. The optic is generally smaller than the diameter of a pupil dilated for night vision, and is surrounded by a snugly fitting annular opaque or semi-opaque ring or frame having a C-shaped cross section and a peripherally extending fin of the same material. The fin is preferably formed of flexible material which is bent during insertion to allow insertion of the two-piece assembly through a minimal size corneal incision. The lens is also provided with position fixation means, such as haptics, which are integrally formed with the lens body and extend outward in the generally horizontal plane of the lens body for seating the lens in the eye. The ring-shaped frame is preferably mated with the lens during manufacturing.

FIELD OF THE INVENTION 
The present invention generally relates to the field of intraocular lenses. 
More specifically, the present invention is for an anterior chamber 
intraocular lens which is capable of being inserted through a small 
incision in the eye and which does not cause any appreciable glare. 
BACKGROUND OF THE INVENTION 
For treating conditions such as natural eye lens cataracts, a known eye 
surgery procedure is to remove the cataracted lens through a minimum size 
incision in the wall of the cornea of the eye, and replace it with an 
implanted artificial intraocular lens. The implantation of an intraocular 
lens is a well known and widely used technique for restoring vision after 
cataract surgery. The natural structure of the eye furnishes a variety of 
locations for fixing the position of the intraocular lens in the eye. For 
example, the intraocular lens can be supported anteriorly of the iris, 
between the scleral spur and the iris. Alternatively, an intraocular lens 
can be supported posteriorly of the iris. In practice, anterior chamber 
lenses are simpler to implant because the anterior chamber angle can be 
viewed by the surgeon while he seats the lens within the eye. Conversely, 
posterior chamber lenses are more difficult to implant, since they are 
seated behind the iris. 
To minimize the possibility of injury to the eye, it is important that the 
incision be made as small as possible. However, the size of the incision 
is generally dictated by the size of the artificial lens which is to be 
implanted. To allow for proper nighttime vision, the artificial lens must 
be sufficiently large to cover the pupil when it is dilated. 
Additionally, the artificial lens should not cause any glare. Glare is 
caused when light passes through an edge or boundary between regions which 
are both substantially transparent. Conversely, there is no glare when 
light passes through an edge or boundary between two regions where at 
least one of the regions is substantially opaque. One example of this 
latter situation is the boundary formed by the iris at its inner edge 
defining the pupil. The iris surrounding the pupil is substantially 
opaque, while the pupil is substantially transparent to allow the passage 
of light to the retina. 
Glare may be eliminated by making the artificial lens, which is 
substantially transparent to light, larger than the size of the dilated 
pupil. In this way, there are no edges or boundaries visible when the 
pupil is dilated. However, this results in a fairly large artificial lens 
requiring a correspondingly large incision in the cornea wall. 
One approach to reducing glare while at the same time reducing the size of 
the incision in the cornea is to construct the artificial lens from 
several pieces which are joined together after the individual pieces are 
inserted through the corneal incision. In this way, the corneal incision 
may be made relatively small, while the resulting artificial lens is 
sufficiently large to properly perform its intended function. One example 
of a multi-piece intraocular lens is disclosed in my earlier U.S. Pat. No. 
4,911,715 issued Mar. 27, 1990, which is incorporated herein by reference. 
The disclosed intraocular lens is implanted in the posterior chamber and 
includes a lens body and a separate ring-shaped collapsible filament and 
tension frame. The frame further includes light masking material. The lens 
and frame are inserted separately into the corneal incision and then 
joined together by inserting tabs on the lens body into opposite receiving 
slits located on the frame. After insertion of the lens body into the 
frame, the light masking material on the frame is positioned over the 
edges of the lens body so as to inhibit light rays directed toward the 
lens body outer edge portions from being scattered thereby. 
Another example of a multi-piece intraocular lens is disclosed in my 
earlier U.S. Pat. No. 5,074,876 issued Dec. 24, 1991, which is 
incorporated herein by reference. The disclosed intraocular lens is 
implanted in the posterior chamber and includes an oblong lens body and a 
collapsible ring-shaped tension frame for receiving the lens body after 
both elements are inserted through the corneal incision. The tension frame 
includes a pair of light masking wing elements located along the longer 
dimension of the frame. The light masking elements are connected to each 
other at their ends by a pair of filaments, each filament connecting one 
corner of a light masking element to a corner of the other light masking 
element. The lens body is tensionally seated within the frame by way of 
grooves formed in the shorter sides of the lens body which engage the 
filaments interconnecting the light masking elements. The lens is also 
positionally maintained with respect to the light masking elements through 
a coacting seating arrangement. 
An alternative approach to intraocular lens design which results in a 
non-glare producing lens and which requires a small incision is to include 
a masking portion at the periphery of the lens. One example of this type 
of intraocular lens is described in my earlier U.S. Pat. No. 4,605,409 
issued Aug. 12, 1986, which is incorporated herein by reference. The 
intraocular lens described therein is implanted in the posterior chamber 
and includes a deformable or moveable pair of masking means integrally 
attached or connected to the lens body. Each member of the masking means 
is moveable between a contracted position which facilitates insertion 
through an incision in the eye, and an expanded position which is attained 
after insertion. In the contracted position, each member of the masking 
means is pivoted to a position underneath the lens body. In the expanded 
position, each member is pivoted out to a position adjacent to and 
overlapping slightly with the peripheral edge of the lens body, thereby 
functioning to reduce or eliminate glare. 
My earlier U.S. Pat. No. 4,833,890 issued May 30, 1989, which is 
incorporated herein by reference, discloses an intraocular lens which is 
implanted in the posterior chamber and has a lens body tensionally mounted 
within a ring-shaped frame. The frame includes contractible peripheral 
light masking wings which surround the lens body. To facilitate insertion 
into the eye through a relatively small corneal incision, the light 
masking wings, which are formed from a resilient material, are folded 
under the lens body. Once the intraocular lens has been inserted into the 
eye, the light masking wings are unfolded and assume their expanded shape 
whereby the light masking wings cover the peripheral edges of the lens 
body, thereby reducing or eliminating any glare. The intraocular lens also 
includes a pair of opposed position fixation means or haptics connected to 
the ring-shaped frame for properly seating the lens in the eye. 
Intraocular lenses for high myopia conditions generally have a thickened 
peripheral portion. However, as the diameter of the lens is increased so 
as to avoid glare conditions, there is a danger that the thickened 
peripheral portion will come in contact with the inner surface of the 
cornea, resulting in potential injury. Alternatively, the diameter of the 
optic or lens body may be reduced in order to avoid the above-mentioned 
peripheral contact. However, in this latter situation, the optic will be 
smaller than the pupil in its dilated condition, resulting in glare caused 
by the light being reflected from the edge of the smaller diameter optic. 
It would be desirable to provide a minimum size intraocular lens for 
implantation in the eye following extracapsular removal of the natural eye 
lens, permitting rapid and efficient lens insertion through the same 
minimum size corneal incision used to remove the natural lens. 
Additionally, it is desirable to provide light masking means for the lens 
body, while utilizing a structurally simple arrangement of parts which are 
readily fabricated at relatively low cost using widely available 
materials. Moreover, it would be desirable to provide a minimum size 
intraocular lens which does not touch the inner surface of the cornea, 
while at the same time not causing any glare. 
OBJECTS OF THE INVENTION 
One of the objects and advantages of the present invention is to overcome 
the drawbacks and inefficiencies of the prior art, and to provide a two 
piece artificial intraocular lens for insertion of the two-piece assembly 
through a minimum size incision into the eye for implantation, e.g., after 
extracapsular removal of the natural eye lens. 
It is an additional object of the present invention to provide an anterior 
chamber two piece intraocular lens of minimum insertion width and having 
individual pieces permitting maximum accommodation of a small size optic 
through a minimum size eye incision, in addition to a frame therefor which 
does not require an incision substantially larger than that which is 
needed for the optic. The two-piece assembly can be rapidly and 
efficiently inserted into the eye, and then implanted, and still provide 
light masking for the optic. 
It is a further object of the present invention to provide a two piece 
anterior chamber intraocular lens which is readily fabricated at 
relatively low cost from widely available materials having desired 
characteristics, and which utilizes a structurally simple arrangement of 
cooperating parts. 
It is yet another object of the present invention to provide a two piece 
anterior chamber intraocular lens for treating high myopia conditions, and 
which does not present the danger of contacting the inner surface of the 
cornea, while at the same time not causing any glare. 
SUMMARY OF THE INVENTION 
The present invention relates to a two piece anterior chamber intraocular 
lens, and more particularly to an artificial intraocular lens for treating 
high myopia conditions by implantation in an eye, such as in the anterior 
chamber, after extracapsular removal of the natural eye lens. The 
two-piece assembly is inserted through a minimum size incision in the eye. 
The lens includes a lens body or optic and a separate ring-shaped tension 
frame therefor containing light masking means for inhibiting light rays 
directed toward the outer edge portions of the lens body from being 
scattered thereby toward the retina after the assembled lens has been 
inserted into the eye. 
The lens body or optic is generally circular and has a maximum diameter of 
approximately 3.5 to 5.0 millimeters. The lens body, or optic, is 
conveniently made of shape retaining plastic. The optic is generally 
smaller than the diameter of a pupil dilated for night vision, and is 
surrounded by a snugly fitting annular opaque or semi-opaque ring or frame 
having a C-shaped cross section and a peripherally extending fin of the 
same material. The lens is also provided with position fixation means, 
such as haptics, which are integrally formed with the lens body and extend 
outward in the generally horizontal plane of the lens body for seating the 
lens in the eye. The haptics and lens body are preferably made of 
polymethylmethacrylate (PMMA). 
The frame is a generally circular shaped element having a C-shaped cross 
section member which provides a groove on the inner circumference of the 
frame for receiving the lens body. Integrally formed with the C-shaped 
cross section member of the frame is a thin, preferably annular fin 
extending radially outward of the C-shaped cross section member. The frame 
is also provided with radially extending notches or slots equal in number 
to the number of haptics used for seating the lens. The radial slots 
provide passageways for connecting the haptics to the lens body. The 
C-shaped cross section member and annular fin are preferably formed of 
optically opaque or translucent material in order to function as light 
masking means. The frame is preferably made of silicone and is preferably 
snapped onto the optic during manufacturing. During insertion into the 
eye, the flexible fin is folded or bent so as to facilitate insertion of 
the assembled two-piece assembly into the eye through a minimal size 
corneal incision. Once the two-piece assembly is inserted into the eye, 
the fin returns to its original radially outwardly extending position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, therein is shown an anterior chamber intraocular 
lens 1 having a central optic portion 2 with an optical axis 2a (shown in 
FIG. 3). Extending from a first peripheral portion 2b of the optic 2 is a 
first fixation element 3. The optic has a second peripheral portion 2c 
spaced from said first mentioned peripheral portion and generally at 
opposite sides of the optical axis 2a with respect to said first mentioned 
peripheral portion. Extending from said second peripheral portion 2c of 
optic 2 is a second position fixation element 4. The position fixation 
elements 3, 4 extend from the optic 2 generally tangentially and in 
generally opposite directions with respect to each other. 
According to the aforesaid construction, there is formed an anterior 
chamber lens 1 which exhibits three-point fixation capability. One or both 
of the position fixation elements, or legs, 3 and 4 is resilient i.e., 
springy, such that it will return to its original undeformed condition 
shown in FIG. 1 after compression of extension away from the illustrated 
configuration. The anterior chamber lens according to the instant 
invention has the important capability of being able to be deformed in 
such manner and to such an extent as to be safely and easily accommodated 
in anterior chamber angles having a wide range of diameters. Thus, 
according to the preferred embodiment of the instant invention, the optic 
2 and the haptics 3 and 4 are manufactured as a unit, of a single piece of 
polymethylmethacrylate (PMMA), or similar biologically inert plastic 
material. Alternatively, the elements 3, 4 may be connected by adhesive or 
ultrasonic welding or any other connection method known in the art. The 
cross-sectional shape, diameter and length of the position fixation 
elements 3 and 4 as well as the angles at which they project from optic 2 
and the amount of curvature of the legs 3a and 4a are all such as to 
facilitate a combined flexure of those elements sufficient to permit 
substantial relative movement between contact surfaces 4c' and 4d', on the 
one hand, and contact surface 3b' on the other hand. 
Referring now to FIG. 2, there is shown a cross section of the intraocular 
lens 1 according to the present invention. Lens 1 includes a lens body 2 
and a ring-shaped tension frame 12 surrounding and holding the lens body 
2. The lens body 2 is generally circular and has a maximum diameter of 
approximately 3.5 to 5.0 millimeters. Lens body 2 is advantageously suited 
for patients suffering from high myopia. Accordingly, lens body 2 has a 
generally flat face 21 (the posterior face) and a generally concave face 
22 (the anterior face). The lens body 2 may be made of shape retaining 
plastic. Frame 12 is generally circular and has a C-shaped cross section 
portion 12' which provides a groove on the inner circumference of the 
frame 12 for receiving and retaining the lens body 2. Integrally formed 
with the C-shaped cross section portion 12' is an annular shaped fin 12" 
extending radially outward. Fin 12" preferably extends 0.3 to 1.0 
millimeters radially outwardly and is typically not centered with respect 
to the cylindrical edge of the lens body 2. Rather, fin 12" is located at 
a horizontal plane which is perpendicular to the optical axis 2a, but 
which is located approximately 0.5 to 1.0 millimeters closer to the 
posterior face 21 than to the horizontal plane passing through the 
anterior peripheral edge of lens body 2. Frame 12 is preferably formed of 
silicone. 
The relatively small diameter of lens body 2 facilitates insertion into the 
eye via a comparatively smaller corneal incision. The addition of frame 12 
surrounding lens body 2 reduces glare associated with light passing 
through lens 1. To achieve this effect, frame 12 is preferably formed of 
optically opaque or translucent material, such as silicone, in order to 
function as a light masking means at the periphery of the lens body 2. 
Lens 1 is particularly suited for high myopia conditions, and as such, is 
greater in thickness at its peripheral portion than at its center portion. 
Normally, in order to avoid glare resulting from light impinging on the 
peripheral edge of the optic, the optic is formed slightly larger in 
diameter than the diameter of the fully dilated pupil. This type of 
construction, however, risks the possible scratching of the inner corneal 
surface due to the wide diameter and increased thickness of the high 
myopia lenses at the peripheral portion thereof. Unfortunately, the 
thickened peripheral portion must be positioned just in the region of the 
eye where the clearance is reduced due to the curvature of the cornea. 
However, the lens of the present invention substantially reduces these 
problems while at the same time still providing an intraocular lens 
suitable for high myopia conditions. The reduced diameter of the lens 
according to the present invention positions the increased peripherally 
thick portion of the lens closer to the center of the eye where there is 
substantially more clearance. Thus, the risk of scratching the inner 
corneal surface is reduced. Moreover, the addition of frame 12 
substantially eliminates any glare normally associated with a reduced 
diameter lens. 
FIGS. 4a--4c illustrate how the reduced diameter of the lens according to 
the present invention is used to substantially eliminate glare. Referring 
now to FIG. 4a, a conventional lens 2' is positioned in front of an iris 
32, which is in a constricted state. Because iris 32 is in a constricted 
state, the iris aperture 34 is smaller in diameter than the diameter of 
lens 2'. Accordingly, there is no glare effect since none of the impinging 
light rays 36 which pass through the aperture 34 pass through the 
peripheral edge of lens 2'. In contrast, FIG. 4b shows a conventional lens 
2' positioned in front of a dilated iris 32. Under these conditions, some 
of the incident light rays 36 which pass through the aperture 34 also pass 
near the peripheral edge of the lens 2', resulting in a perceived glare. 
FIG. 4c shows the lens 1 of the present invention positioned in front of a 
dilated iris 32. As shown in FIG. 4c, the incident light rays 36 which 
pass near the peripheral edge of the lens 1 are impeded from reaching the 
iris aperture 34 because of the presence of frame 12 which acts as a light 
masking means. In this way, although the diameter of lens 1 is smaller 
than the diameter of the aperture 34 caused by the dilated iris 32, 
nevertheless, there is no glare because of the light masking effect of the 
frame 12. 
Frame 12 is also provided with radially extending notches or slots 14 (FIG. 
3) for the haptics or position fixation members 3 and 4. The radial slots 
14 provide passageways for the haptics 3, 4, which are integral with the 
lens body 2. Alternatively, the haptics 3, 4 may be integrally formed with 
the frame 12. In this latter embodiment, the radial slots 14 would not be 
needed. 
Insertion of the lens 1 according to the present invention is accomplished 
by inserting the lens assembly 1, i.e., the lens body 2 and frame 12, via 
the corneal incision. During insertion into the eye, the thin, flexible 
fin 12" is folded or bent towards the lens body 2 so as to facilitate 
insertion of the two-piece lens assembly 1 into the eye through a minimal 
size corneal incision. Once the two-piece assembly 1 is inserted into the 
eye, the fin 12" returns to its original position extending radially 
outward of the lens body 2 and C-shaped cross section member 12'. In this 
way, the two-piece lens assembly 1 is inserted through a corneal incision 
which is only slightly larger than that needed for the lens body 2. The 
two piece construction of lens 1 having a resilient fin facilitates 
exploitation of the minimum size corneal incision used by the surgeon for 
extracapsular removal of the natural eye lens. This is particularly 
significant since, understandably, the smaller the corneal incision size 
the less trauma experienced by the patient, and in turn, the less the pain 
and discomfort endured then and thereafter, not only because of the 
incision itself but also because of the number and/or size of any needed 
sutures. 
While the invention has been particularly shown and described with 
reference to a preferred embodiment thereof, it will be understood by 
those skilled in the art that various changes in form and details may be 
made therein without departing from the spirit and scope of the invention.