Flexible anterior chamber lens

An anterior chamber lens implant is provided which is designed to be implanted in the eye after the natural lens of the eye has been surgically removed. In each of the three embodiments disclosed herein, the implants include a disc-shaped lens having four flexible holding members extending therefrom so as to be completely independently flexible of the other holding members. Each of the holding members of the lens implants includes leg portions and foot portions. The holding members are flexibly designed so as to be flexibly movable rearwardly, forwardly, inwardly and outwardly.

BACKGROUND OF THE INVENTION 
This invention relates to an anterior chamber lens. 
The human eye is a very complex organ comprising numerous interacting 
elements which gather, focus, and transmit light rays to nerve endings 
which eventually transmit the information to the brain for image 
perception. The eye includes a natural crystalline lens of avascular 
tissue, the transparency of which depends upon the critical regularity of 
its fibers and the balance of its chemical constituents. Obviously, there 
are enumerable factors which may interfere with lens makeup and thereby 
affect its transparent character. No matter what the reason, a condition 
of opacity in the lens, commonly called cataract, reduces the visual 
performance of the eye. When the visual performance is reduced to an 
unacceptable level, surgical cataract extraction becomes a necessity. 
An eye without a lens, a condition called aphakia, is obviously defective 
from an optical point of view in as much as it cannot properly refract 
incident light rays. Aphakic correction may be accomplished in three ways: 
(1) thick eye glasses worn in front of the eye; 
(2) contact lenses worn on the eye; or 
(3) artificial intraocular lens implant within the eye. 
It is this latter procedure with which the instant invention is concerned. 
The structure and procedure of installing an intraocular lens is very 
critical because the elements which make up the eye are extremely 
sensitive and subject to irreparable damage. Numerous experimental lens 
designs have been abandoned through the years because they caused corneal 
damage and other manifestations of intraocular irritation. For example, in 
the late 1940's and early 1950's, H. Ridley conducted clinical experiments 
with an artificial intraocular lens which included a lens portion having 
foot-like projections extending radially away therefrom. This device was 
placed in the posterior chamber with the feet extending between the 
ciliary processes and the base of the iris. The lens proved positionally 
unstable and resulted in unsatisfactory amounts of irritation. 
Logically, the anterior chamber of the eye was next investigated as a 
possible location for the implant. Here again, efforts have been less than 
satisfactory because of irritation and positional instability. 
The lens described in U.S. Pat. No. 3,673,616 comprises an anteriorly 
positioned lens with two supporting loops affixed thereto for arrangement 
behind the iris. A plurality of rods also project from the lens for 
arrangement in front of the iris. The iris expands and contracts between 
the rods and loops, but never completely expands beyond the space 
therebetween, thus holding the lens in position. The problems associated 
with a free-floating lens of this type are numerous. For example, the lens 
is not fixed in position and is therefore subject to a wide range of 
positional variation. Also, the iris is subjected in numerous locations to 
pressure necrosis caused by the rods rubbing against the iris. 
Another device similar to that described immediately above is shown in U.S. 
Pat. No. 3,906,551. This particular prosthetic lens includes a pair of 
closely spaced apertures through which suturing threads are inserted for 
transversely fixing the lens in position. 
U.S. Pat. No. 3,866,249 discloses a posteriorly positioned prosthetic lens 
which has a multiplicity of forwardly projecting prongs. During surgical 
implantation, the prongs are extended through the iris to anchor the lens 
in position. While this arrangement certainly maintains positional 
integrity, it, too, has distinct disadvantages. The great number of prongs 
extending through and over the iris promote undesirable irritational 
characteristics, and the numerous fixation points also have a tendency to 
distort the iris by pulling on it in numerous directions. 
Finally, attention is directed to the lenses disclosed in U.S. Pat. Nos. 
3,925,825; 3,913,148; and 3,922,728. Each of these patents teach a 
prosthetic lens structure which is, in one way or another, less than 
desirable in construction and use. 
In an effort to remedy the problems associated with the prior art lens 
implants, applicant previously has been granted U.S. Pat. Nos. 4,143,427; 
4,166,293 and 4,251,887. Other recent developments relating to implant 
lens may be found in U.S. Pat. Nos. 4,316,293 and 4,340,979. 
Although the prior art devices have been used with some success, it has 
been found that the closed loops such as described in U.S. Pat. No. 
4,316,293 do not provide the necessary stability due to the fact that 
pressure on one portion of the loop causes deflection of the entire loop. 
The same is also true for the "J" type loops such as illustrated in U.S. 
Pat. No. 4,340,979. 
Therefore, it is a principal object of this invention to provide an 
improved anterior chamber lens. 
A further object of the invention is to provide an anterior chamber lens 
wherein four holding or positioning members extend from the lens in such a 
manner so that each of the holding members provide independent suspension 
and support for the lens. 
Still another object of the invention is to provide an anterior chamber 
lens wherein the four holding members may flex rearwardly, forwardly, 
upwardly and downwardly independently of each other. 
Still another object of the invention is to provide an anterior chamber 
lens which will not cause irritation. 
Still another object of the invention is to provide an anterior chamber 
lens which will remain in place even if pressure or force is inadvertently 
applied to one portion of the lens. 
These and other objects will be apparent to those skilled in the art.

SUMMARY OF THE INVENTION 
An anterior chamber lens implant is described which may be implanted in the 
eye after the natural lens of the eye has been removed. Although there are 
three embodiments of the invention described herein, all of the 
embodiments include a disc-shaped lens having a front face, a rear face, 
an outer peripheral edge including upper and lower ends, and first and 
second sides. Four flexible holding members extend from the lens in such a 
manner so as to be completely independently flexible of the other holding 
members. In one form of the invention, a pair of the holding members are 
secured to the upper peripheral edge of the lens with a pair of the 
holding members being secured to the lower peripheral edge of the lens. 
The upper holding members include leg portions which extend upwardly and 
inwardly from the lens and foot portions extending laterally outwardly 
therefrom. Likewise, the lower holding members each include leg portions 
which extend downwardly and inwardly from the lens and foot portions at 
the lower ends thereof which extend laterally outwardly therefrom. In the 
other two embodiments of the invention, the leg portions of the holding 
members are arcuate and are equally spaced along their length from the 
peripheral edge of the lens. 
DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIGS. 3, 6 and 9, the numeral 10 refers to an eye, after cataract 
removal by surgical procedure. Eye 10 includes a cornea 12 which merges 
into an opaque protective covering 14 called sclera. Behind the cornea 12 
is the iris 16 which defines a central opening 18 known as the pupil. The 
iris 16 comprises a muscular diaphragm-like element capable of expansion 
and contraction to control the amount of light passed therethrough. The 
iris divides the internal chamber of the eye into two chambers, the 
anterior chamber 20 and the posterior chamber 22. The natural crystalline 
lens of the eye would be located in the posterior chamber 22 adjacent to 
pupil 18. 
The lens implant 24 of FIGS. 1 and 2, the lens implant 26 of FIGS. 4 and 5, 
and the lens implant 28 of FIGS. 7 and 8 are each designed to be 
positioned within the anterior chamber 20 in contact with the forward 
portion of the iris 16 with the holding or fixation members impacting 
against the sclera spur in the angle of the anterior chamber. 
Referring to FIGS. 1-3, lens implant 24 comprises a disc-shaped lens 30 
having a front face 32, rear face 34, and an outer peripheral edge 36. For 
purposes of description, lens 32 will be described as having an upper end 
38, lower end 40, and opposite sides 42 and 44. 
Lens 30 is provided with four holding or fixation members 46, 48, 50 and 52 
integrally formed therewith and which extend therefrom at approximately 
eleven o'clock, one o'clock, seven o'clock and five o'clock, respectively. 
Holding member 46 includes an elongated leg portion 54 extending inwardly 
and upwardly from peripheral edge 36 and a foot portion 56 which extends 
laterally outwardly from the upper end of leg portion 54. Similarly, 
holding member 48 includes leg portion 58 and foot portion 60. Holding 
member 50 is comprised of leg portion 62 and foot portion 64 while holding 
member 52 is comprised of leg portion 66 and foot portion 68. As seen in 
FIG. 1, the leg portions 54, 56, 62 and 66 extend from lens 32 
insubstantially a tangential relationship with respect to the outer 
peripheral edge of the lens 32. As also seen in the drawings, the outer 
ends of the foot portions are provided with openings formed therein 
referred to generally by the reference numeral 70. FIG. 2 illustrates the 
fact that the leg portions of the holding elements also extend rearwardly 
as they extend outwardly from lens 32. As seen in FIG. 1, the juncture of 
each of the leg portions and foot portions is curved at 72 to permit the 
foot portion to flex upwardly and downwardly as well as rearwardly and 
forwardly with respect to the associated leg portion. The connection of 
the leg portions with the lens also permits the leg portions to flex 
inwardly and outwardly as well as rearwardly and forwardly with respect to 
the lens 30. 
Referring to FIGS. 4-6, lens implant 26 includes a disc-shaped lens 74 
having mounting projections 76 and 78 extending laterally therefrom at the 
opposite sides thereof. Lens 74 is identical to lens 32 except for the 
manner in which the holding elements are affixed thereto. Holding member 
80 extends from projection 76 and comprises an arcuate leg portion 82 
which extends upwardly and inwardly from projection 76. Intermediate 
portion 84 of holding member 80 extends upwardly from the upper end of leg 
portion 82. It can be seen in FIG. 4 that foot portion 86 extends upwardly 
and outwardly from the upper end of intermediate portion 84. It can also 
be seen in FIG. 4 that leg portion 82 is spaced from the outer peripheral 
edge of the lens element 74 and is generally arranged in a concentric 
fashion with respect thereto. Similarly, holding member 88 extends 
upwardly from projection 78 while holding members 90 and 92 extend 
downwardly from projections 76 and 78, respectively. The connection of the 
foot portions with the intermediate portions permit the foot portions to 
flex upwardly, downwardly, rearwardly or forwardly. Likewise, the leg 
portions of the holding members may also flex inwardly, outwardly, 
rearwardly or forwardly due to their connection with the projections 76 or 
78. 
The lens implant 28 of FIGS. 7-9 is substantially identical to lens implant 
26 except that the mounting projections 94 and 96 in lens implant 28 have 
a vertical height slightly less than that of the mounting projections 76 
and 78 in lens implant 26. Another difference between the lens implants 26 
and 28 is that the outer portions of the projections 94 and 96 are arcuate 
or curved and dwell in substantially the same plane as the outside 
surfaces of the leg portions of the holding members. 
Referring to the lens implant 24 of FIGS. 1-3, the lens 12 may be of any 
suitable diameter, but generally falls somewhere in the range of 6 
millimeters. It should be realized that the parameters and ranges given 
herein are merely exemplary and that actual optical and surgical variables 
are subjectively determined by the opthamologic surgeon in charge of the 
patient. The lens 30 may be of any suitable material which may be made to 
exhibit the proper optical characteristics, and which is biologically 
inert. The most suitable material known for such lens implants is 
substantially polymethylmethacrylate, a compound commonly used in contact 
lens manufacture. Other suitable materials include quartz, opthalmic glass 
and polymeric materials. The overall length/diameter of the implant 24 is 
preferably 13.0 millimeters. The preferred width of the leg portions and 
foot portions of the implant 24 is 0.17 millimeters while the preferred 
thickness of the foot portions and leg portions is preferably 0.24 
millimeters. The overall width of the implant 24 is preferably 8.0 to 8.5 
millimeters. 
Referring to the lens implant 26 of FIGS. 4-6, the overall length/diameter 
of the same is preferably 13.0 to 13.5 millimeters with the lens 74 
preferably having a diameter of 5.5 millimeters. The preferred distance 
between the outer edges of the projections 76 and 78 is 7.0 millimeters 
thereby providing a width to the projections 76 and 78 of 0.75 
millimeters. The preferred distance between the intermediate portions on 
the implant is 1.0 millimeters. The foot portions and leg portions of the 
lens implant 26 preferably have the same widths and thicknesses as that of 
lens implant 24. 
Referring to the lens implant 28 of FIGS. 7-9, the dimensions thereof are 
substantially the same as the embodiment of FIGS. 4-6 with a few 
exceptions. In lens implant 28, the lens 74 preferably has a diameter of 
5.0 millimeters with the distance between the outer edges of the 
projections 94 and 96 being preferably 7.0 millimeters which results in 
the width of the projections 94 and 96 being 1.0 millimeters. 
In each of the lens implant embodiments, the lens thereof may generally 
have any suitable cross-sectional configuration; however, it has been 
found that a flat rear surface more easily accommodates an expanding and 
contracting pupil, and that the front surface thereof may be modified to 
provide the desired optical characteristics. 
The lens implants of this invention are positioned in the anterior chamber 
of the eye through acceptable surgical procedures. When the implants are 
in position such as illustrated in FIGS. 3, 6 and 9, the foot portions 
thereof impact against the sclera spur in the angle of the anterior 
chamber. When the lens implants have been implanted, the foot portions 
thereof will exert sufficient force on the sclera spur to aid in 
maintaining the implant in position. Each of the holding members 
independently supports and suspends the implant in position to achieve the 
desirable positional stability. In the event that inadvertent pressure is 
applied to one of the holding members of the implant, that particular 
holding member will flex or deflect without adversely affecting the 
positional stability of the remaining holding members. Inadvertent 
pressure imposed on the lens itself will not cause objectionable movement 
of the holding members due to their flexible attachment to the lenses. 
Thus it can be seen that the lens implant of this invention accomplishes at 
least all of its stated objectives.