Anterior chamber intraocular lens with four point fixation

An intraocular lens for implant in the anterior chamber has four fixation members extending from a lens body with the lens body having curved, opposed end peripheral edges and curved side peripheral edges, the radius of curvature of the end peripheral edges being less than the radius of curvature of the side peripheral edges and the fixation members extending from the junctions of the end and side peripheral edges and having continuously curved proximal legs, junction portions and distal legs terminating at footplates to be received in the angle of intesection of the cornea and iris such that the fixation members flex along their entire length in response to forces applied to the footplates.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to artificial lenses for the eye and, more 
particularly, to intraocular lenses for implant in the anterior chamber of 
the eye. 
2. Discussion of the Prior Art 
The implantation of an artificial intraocular lens in an eye after removal 
of the natural lens due to a blindness-causing condition, such as 
cataract, has become an accepted practice. Such intraocular lenses are 
normally positioned in the posterior chamber of the eye, secured to the 
iris, or positioned in the anterior chamber of the eye. Many surgeons 
prefer anterior chamber intraocular lenses since implant in the anterior 
chamber is easier for the surgeon than implant in the posterior chamber; 
and, additionally, in many cases only anterior chamber intraocular lenses 
can be implanted due to medical considerations. Many intraocular lenses 
designed for implant in the anterior chamber have suffered the 
disadvantages of creating medical problems due to stiffness, requiring 
many sizes to be available for eyes of different sizes and causing too 
much pressure against the angle structure where the cornea and iris 
intersect inducing various elements of the UGH syndrome and unacceptably 
high incidence of cystoid macula edema. 
U.S. Pat. No. 4,575,374 to Anis discloses a four point fixation intraocular 
lens for implant in the anterior chamber; however, the embodiment 
illustrated in FIG. 1 is insufficiently flexible inwardly and outwardly 
while being too flexible rearwardly and forwardly thereby providing 
increased opportunity for iritis and/or cornea damage to occur. To this 
end, it is noted that the foot portions are designed to flex independently 
of the leg portions with the leg portions being insufficiently flexible by 
design. With respect to the embodiments of FIGS. 4 and 7, projections 
extend laterally from opposite sides of the lens body creating a structure 
difficult to implant through a minimal incision; and, additionally, the 
holding members are provided with intermediate portions such that the foot 
portions flex independently of the leg portions. Additionally, the 
intraocular lenses of both embodiments are designed to be positioned 
within the anterior chamber in contact with the forward portion of the 
iris. 
SUMMARY OF THE INVENTION 
Accordingly, it is a primary object of the present invention to overcome 
the above mentioned disadvantages of the prior art by providing an 
intraocular lens for positioning in the anterior chamber of the eye having 
four fixation members flexible along their entire lengths in response to 
forces applied to footplates at the ends of the fixation members for 
positioning in the angle of intersection of the cornea and the iris. 
Another object of the present invention is to construct an intraocular lens 
for implant in the anterior chamber of an eye having four fixation members 
having continuous curving configurations throughout the lengths thereof to 
provide maximum flexibility inwardly and outwardly. 
A further object of the present invention is to provide an anterior chamber 
intraocular lens having four fixation members flexibly independent of each 
other, the intraocular lens being positioned in the anterior chamber so as 
to be spaced from the iris with minimal forward and rearward flexing. 
The present invention has another object in that a four point fixation 
anterior chamber intraocular lens has four independently flexible fixation 
members and can be easily inserted in the anterior chamber through an 
incision having a length substantially the same a the width of the lens 
body of the intraocular lens. 
Yet another object of the present invention is to provide an anterior 
chamber intraocular lens having a lens body with curved end peripheral 
edges disposed at opposed positions along a longitudinal axis to permit 
the longitudinal axis to be aligned with tears or irregularities in the 
iris. 
Some of the advantages of the present invention over the prior art are that 
the anterior chamber intraocular lens of the present invention is 
extremely stable in the anterior chamber while permitting independent 
flexing of the fixation members, the anterior chamber intraocular lens can 
be easily implanted using simple maneuvers and an incision for implant of 
the lens need have a length only substantially the same as the width of 
the lens body. 
The present invention is generally characterized in an intraocular lens for 
implant in the anterior chamber of an eye including a lens body having a 
configuration to define first and second opposed end peripheral edges, 
first and second opposed side peripheral edges connecting the first and 
second end peripheral edges and a longitudinal axis extending centrally 
through the first and second end peripheral edges, the first and second 
end peripheral edges being curved and the first and second side peripheral 
edges being curved with the radius of curvature of the first and second 
end peripheral edges being less than the radius of curvature of the first 
and second side peripheral edges; a first fixation member connected with 
the first side peripheral edge including a continuously curving proximal 
leg extending toward and beyond the first end peripheral edge and toward 
the longitudinal axis, a continuously curving junction portion connected 
with the proximal leg, and a continuously curving distal leg connected 
with the junction portion to extend in a direction substantially 
transverse to and away from the longitudinal axis to terminate at a 
footplate adapted to be received in the angle of intersection of the 
cornea and the iris in the anterior chamber of an eye; a second fixation 
member connected with the first side peripheral edge including a 
continuously curving proximal leg extending toward and beyond the second 
end peripheral edge and toward the longitudinal axis, a continuously 
curving junction leg connected with the proximal leg, and a continuously 
curving distal portion connected with the junction portion to extend in a 
direction substantially transverse to and away from the longitudinal axis 
to terminate at a footplate adapted to be received in the angle of 
intersection of the cornea and the iris in the anterior chamber of an eye; 
a third fixation member connected with the second side peripheral edge 
including a continuously curving proximal leg extending toward and beyond 
the first end peripheral edge and toward the longitudinal axis, a 
continuously curving junction portion connected with the proximal leg, and 
a continuously curving distal leg connected with the junction portion to 
extend in a direction substantially transverse to and away from the 
longitudinal axis to terminate at a footplate adapted to be received in 
the angle of intersection of the cornea and the iris in the anterior 
chamber of an eye; and a fourth fixation member connected with the second 
side peripheral edge including a continuously curving proximal leg 
extending toward and beyond the second end peripheral edge and toward the 
longitudinal axis, a continuously curving junction portion connected with 
the proximal leg, and a continuously curving distal leg connected with the 
junction portion to extend in a direction substantially transverse to and 
away from the longitudinal axis to terminate at a footplate adapted to be 
received in the angle of intersection of the cornea and the iris in the 
anterior chamber of an eye, the junction portions of the first and third 
fixation members being disposed in laterally aligned spaced relation on 
opposite sides of the longitudinal axis at radial distances from the first 
end peripheral edge less than radial distances of the footplates of the 
first and third fixation members from the first end peripheral edge and 
the junction portions of the second and fourth fixation members being 
disposed in laterally aligned spaced relation on opposite sides of the 
longitudinal axis at radial distances from the second end peripheral edge 
less than the radial distances of the footplates of the second and fourth 
fixation members from the second end peripheral edge, and the lens body 
and the fixation members being integrally made of one piece of plastic 
material with the fixation members having continuous curving 
configurations throughout the lengths thereof to flex along the full 
lengths in response to forces radially applied to the footplates. 
Other objects and advantages of the present invention will become apparent 
from the following description of the preferred embodiment taken in 
conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
An intraocular lens 10 according to the present invention is shown in FIGS. 
1 and 2 and includes a lens body or optic 12 having a convex anterior 
surface 14 and a flat or planar posterior surface 16 such that the lens 
body serves to focus light on the retina in the manner of the natural lens 
of the eye. The lens body is symmetrical about a longitudinal axis shown 
in dashed lines at 18 and is also symmetrical about a lateral axis shown 
in dashed lines at 20. The lens body has curved, opposed end peripheral 
edges 22 and 24 interconnected by curved, opposed side peripheral edges 26 
and 28, and the end peripheral edges 22 and 24 are curved with a radius of 
curvature less than the radius of curvature of the side peripheral edges 
26 and 28. 
A fixation member 30 is connected with side peripheral edge 26 and includes 
a proximal leg 32 extending tangentially from said peripheral edge 26 
toward and beyond end peripheral edge 22 and toward longitudinal axis 18, 
a junction portion 34 connected with proximal leg 32 and curving into a 
distal leg 36 extending substantially transversely away from longitudinal 
axis 18 to terminate at a footplate 38. 
A fixation member 40 is connected with side peripheral edge 26 and includes 
a proximal leg 42 tangentially from side peripheral edge 26 toward and 
beyond end peripheral edge 24 and toward longitudinal axis 18, a junction 
portion 46 connected with proximal leg 42 and curving into a distal leg 46 
extending substantially transversely away from longitudinal axis 18 to 
terminate at a footplate 48. 
A fixation member 50 is connected with side peripheral edge 28 and includes 
a proximal leg 52 tangentially from side peripheral edge 28 toward and 
beyond end peripheral edge 22 and toward longitudinal axis 18, a junction 
portion 54 connected with proximal leg 52 and curving into a distal leg 48 
extending substantially transversely away from longitudinal axis 18 to 
terminate at a footplate 48. 
A fixation member 60 is connected with side peripheral edge 28 and includes 
a proximal leg 62 tangentially from side peripheral edge 28 toward and 
beyond end peripheral edge 24 and toward longitudinal axis 18, a junction 
portion 64 connected with proximal leg 62 and curving into a distal leg 66 
extending substantially transversely away from longitudinal axis 18 to 
terminate at a footplate 68. 
Each of the fixation members 30, 40, 50 and 60 is continuously curving 
throughout the length thereof with each of the proximal and distal legs 
and the junction portion also continuously curving such that an extremely 
long fulcrum arm is created flexible along its entire length in response 
to forces applied to the footplates which are received in the angle of 
intersection of the cornea and the iris as will be described in more 
detail hereinafter. 
The entire intraocular lens 10 including the lens body 12 and the fixation 
members 30, 40, 50 and 60 is integrally made of one piece non-toxic 
plastic, such as polymethylmethacrylate, with the lens body having a 
desired prescription. The radius of curvature of the side peripheral edges 
26 and 28 is preferably 3.0 mm while the radius of curvature of the end 
peripheral edges 22 and 24 is preferably 2.0 mm such that recesses 70, 72, 
74 and 76 are formed between fixation members 30, 40, 50 and 60, 
respectively, and the edges of the lens body to increase flexibility of 
the fixation members inwardly and outwardly that is toward and away from 
the lens body. The distance between diametrically opposed recesses 70, 72, 
74 and 76 is preferably 5 mm while the distance between the opposed end 
peripheral edges 22 and 24 is 6.0 mm. The inside radius of curvature of 
the recesses 70, 72, 74 and 76 is preferably 0.45 mm and each of the 
proximal legs of the fixation members extends from the side peripheral 
edges at an initial curvature of 3.15 mm curving toward the longitudinal 
axis, the initial portion extending over approximately 65% of the length 
of the proximal leg, and thereafter curving away, slightly, from the 
longitudinal axis with a radius of curvature of 3.69 mm prior to 
connection with the junction portion which has an outside radius curvature 
of 0.70 mm smoothly curving into the distal leg which has a radius of 
curvature of 2.1 mm in a reverse direction to the curve of the junction 
portion. The footplate has a radius of curvature of 0.48 mm. The fixation 
members have a width of 0.24 mm and a depth or caliper of 0.32 mm with a 
rounded rectangular-like configuration in cross section. The distance 
between diametrically opposed footplates 38, 68 and 48, 58 is 13.5 mm to 
permit the intraocular lens to be received in anterior chambers having 
various diameters within the normal range. The fixation members extend 
from the lens body at an angle of about 10.degree. to space the posterior 
surface 16 of the lens body from the lower surface of the footplates by a 
distance of 0.50 mm, this angulation or vaulting of the fixation members 
being illustrated in FIG. 2. 
The intraocular lens 10 can be very easily implanted in the anterior 
chamber of an eye as shown in FIGS. 3, 4, 5, 6 and 7 wherein an eye 78 is 
shown with an iris 79 and a incision 80 of a length from 6.0 to 6.5 mm. To 
implant the intraocular lens 10, the lens body 12 is held by a standard 
Shepard or Clayman type intraocular lens holder 81 at twelve o'clock and 
inferior fixation member 60 is introduced through the incision and moved 
to the side as shown by the arrow 82 to permit inferior fixation member 40 
to move through the incision such that the intraocular lens 10 is no in 
the position illustrated in FIG. 4 with inferior fixation members 40 and 
60 in the anterior chamber. The intraocular lens is now advanced directly 
radially into the anterior chamber to the six o'clock position as shown by 
the arrow 84; and, when the footplates 48 and 68 of the inferior fixation 
members are seated in the angle of intersection between the cornea and the 
iris as illustrated in FIG. 5, the inferior fixation members can be 
compressed sufficiently to allow the superior fixation members 30 and 50 
to move into the anterior chamber in a single movement such that, when the 
lens body is released, the footplates 38 and 58 of the superior fixation 
members will seat in the angle and the intraocular lens will center 
itself. Alternatively, the intraocular lens can be released once it is in 
the position illustrated in FIG. 5, and the superior fixation members 30 
and 50 grasped one at a time with a MacPherson type forceps 86 and 
introduced into the anterior chamber through the incision allowing the 
footplates 38 and 58 to be seated in the angle. During the maneuvers 
illustrated in FIGS. 6 and 7, the intraocular lens 10 will be moved 
slightly to the left and to the right respectively, and it will be 
appreciated that the inferior fixation members 40 and 50 flex along their 
entire lengths, as shown, to permit this movement. 
The intraocular lens 10 is shown in FIGS. 8 and 9 after implant in the 
anterior chamber; and, it will be appreciated that each fixation member 
contacts the angle only at its footplate to provide maximum stability by 
four point fixation with minimum drainage blockage in the angle. 
Additionally, it can be seen from FIG. 8, that the fixation members flex 
along their entire lengths due to the continuously curving configurations 
thereof. More particularly, the proximal legs flex inwardly toward the 
lens body as do the distal legs with the smooth continuous curve of the 
junctions allowing movement of the fixation members toward the 
longitudinal axis and towards the lens body while creating no stress 
points and minimizing the possibility of breakage. The vaulting or 
angulation of the fixation members spaces the posterior surface 16 of the 
lens body 12 from the iris 79, as shown in FIG. 9. 
With the proximal legs joining the distal legs via the smoothly curved 
junction portions, any radially applied force on a footplate of a fixation 
member flexes both the distal and proximal legs establishing each fixation 
member as a very long and flexible, single fulcrum member with all 
portions thereof acting in concert rather than being isolated from each 
other. The slight inward curvature of the distal legs increases the 
fulcrum length; and, since the distal legs extend substantially 
transversely to the longitudinal axis, the radial vector from any force 
applied to the footplates is minimized. 
The junction portions of the inferior fixation members 40 and 60 and the 
superior fixation members are laterally aligned in spaced relation on 
opposite sides of the longitudinal axis 18 and are located at distances 
less from the end peripheral edges less than the distance of the 
footplates from the end peripheral edges to permit maximum flexibility, 
and the fulcrum length of the fixation members is increased by curving the 
distal legs of the fixation members toward the end peripheral edges of the 
lens body. 
Inasmuch as the present invention is subject to many variations, 
modifications and changes in detail, it is intended that all subject 
matter discussed above or shown in the accompanying drawings be 
interpreted as illustrative only and not to be taken in a limiting sense.