Intraocular Lens

This invention relates to structures for making an improved lens implant, as a replacement for a cataract-clouded or otherwise diseased natural lens. The invention represents improvement over structures described in my U.S. Pat. No. 4,122,556 and over my various other patent disclosures referred to in said patent. Reference is therefore made to said patent and disclosures for greater background detail as to structure, and manufacturing and manipulating technique.

Regardless of the structure of an intraocular lens and its mount, relatively great skill is required for installation at or through an iris opening, if post-operative trauma are to be avoided. The likelihood of such trauma is also reduced, to the extent that lens mounting structure imposes least restriction upon normal aperture responses of the iris.

It is an object of the invention to provide improved mounting structure for an intraocular lens.

Another object is to provide such structure lending itself to simplified installation through the iris.

It is a specific object to provide such structure with stabilizing means placing virtually no restriction upon the iris, as compared with prior constructions.

It is another specific object to provide such structure with stabilizing means adapted to provide lens-positioning support within and from the inner wall of the crystalline-lens sac, following invasive surgery to remove cataracted material from the sac.

It is also a specific object to provide such structure which lends itself to posterior implantation in a human eye and which is inherently resistive against such secondary membrane growth (i.e., corpuscular regrowth) as might otherwise obscure or degrade optical performance of the implanted lens.

Still another specific object is to achieve the above objects with structure which is inherently capable of securely and accurately positioning an optically finished glass lens element.

The foregoing and other objects and features of the invention are achieved in illustrative forms of an annular adapter which axially retains itself against both axial sides of the peripheral rim of the lens element to which it is assembled. And plural axially compliant stabilizing feet are provided as radially outward projections from the radially outer edge of the annular body of the adapter. Apertures in the feet enable a suture through all the apertures to temporarily hold all feet in radially retracted position, to facilitate operative insertion of the lens and its adapter via the pupil into the posterior chamber, and into the sac from which cataracted natural lens material has been removed. Upon withdrawal of the suture, the feet are released, to conform to the inner wall of the sac, for stabilized positioning of the lens.

Preferred embodiments of the invention are shown in the accompanying drawings, taken in conjunction with ensuing text. In said drawings;

FIG. 1 is a view in elevation of an intraocular lens of the invention, complete with assembled mounting structure;

FIGS. 2 and 3 are blank outlines of the respective mounting parts employed in the structure of FIG. 1;

FIGS. 4 and 5 are simplified and somewhat schematic sectional views to show alternative installed implantations of the lens and mount of FIGS. 1 to 3; and

FIGS. 6 and 7 are views similar to FIG. 1 to show modifications.

In FIGS. 1 to 3, the invention is shown in application to mounting structure for a finished optical lens element 10 to be surgically implanted in a human eye, relying upon posterior-chamber features for stabilized support of the implant. The mounting structure comprises two parts, a stabilizing-foot part 11 (FIG. 2) and a locking-ring part 12 (FIG. 3), which parts circumferentially continuously overlap opposite axial sides of the rim or peripheral region of lens 10 and which are connected to each other at angularly spaced locations adjacent the lens periphery. Each of these parts, such as the part 11, is characterized by a circumferentially continuous body portion 13 having a circular inner edge of diameter D.sub.1 less than the diameter D.sub.2 of lens 10 and otherwise in full radial overlap with the lens periphery; because of similarity of certain features of both the part 11 and the part 12, the same identifying numbers as used in FIG. 2 are adopted for corresponding features of FIG. 3, with primed notation. Thus, with the parts 11-12 assembled to each other and to lens element 10 in FIG. 1, the body portion 13 of the part 11 circumferentially continuously laps one side (e.g., the posterior side) of the peripheral region of the lens element, and the body portion 13' of the other part 12 similarly laps the corresponding peripheral region of the opposite side (e.g., the anterior side) of the lens element.

For connected assembly of parts 11-12 to each other, the peripheral regions of both body portions 13-13' are similarly formed with hook and slot formations having diametrically opposite symmetry in diametrically opposite quadrants about the central optical axis. Thus, within a first pair of diametrically opposed quadrants, first and second diametrically symmetrical extensive arcuate tab projections 14-15 are formed with arcuate slots 16-17, of substantial angular extent .alpha..sub.1 approaching but less than 90 degrees. And within the remaining or second pair of diametrically opposed quadrants, first and second pairs of diametrically symmetrical hook formations 18-19 and 20-21 project in the circumferentially outward direction with respect to the involved quadrant. The hook formations of member 11 are designed for interlocked engagement in the arcuate-slot formations 16'-17' of member 12, while the hook formations 18'-19' and 20'-21' of member 12 have interlocked engagement in the arcuate-slot formations 16-17 of member 11. To this end, the hook ends in a given quadrant are at an angular spread .alpha..sub.2 which exceeds the effective slot width .alpha..sub.1 , and the closed end of the hook openings in a given quadrant are at an angular spread .alpha..sub.3 which is less than the effective slot width .alpha..sub.1.

The fully assembled structure is seen in FIG. 1 to involve eight angularly spaced hook-to-slot interlocking engagements around the rim of lens element 10. The hook and slot patterns of the respective parts 11-12 are 90-degrees offset with respect to each other, to enable the described interlocking relation. And the lens element 10 is positively retained by and between circumferentially continuous body surfaces 13-13', with concentric mounting assured by the eight interlocking engagements. Finally, short radially outward integral tab formations 25-26 (25'-26'), between adjacent hook formations 18-19 and 20-21, radially overlap central regions of slotted projections 14'-15' (14-15) to provide additional mutuality of body-member support.

The body member 11 is integrally formed with plural radial foot projections 111 which extend from angularly spaced locations on the basic body ring 13, to an overall diametral extent D.sub.3, say 10 to 11.5 mm, which exceeds the maximum available mounting diameter within an excavated lens capsule or sac. A slotted region 112 in each of the foot projections 111 renders them more bendable and hence more capable of gentle radially compliant suspension of the mounted lens 10, the radial extent R.sub.1 -R.sub.2 between inner and outer slot limits being selected to be primarily within (i.e., less than) but nevertheless preferably to include the available mounting radius R.sub.3 (about 5.5 mm) within the excavated sac 113 (see FIG. 4). In one illustrative operative procedure, a lens 10 mounted by assembled body members 11-12 is transported through the iris opening, using a single releasable filament through all slots, for transient overall size reduction, and using a manipulative tool having releasable engagement with the lens rim. Once past the iris, and suitably oriented, the filament is withdrawn, thereby releasing all feet to restore their FIG. 2 appearance, the feet 111 being then in a radial plane between the iris and the excavated sac 113. The assembly is then further inserted into the sac 113 until feet 111 become deflected and retained by sac-wall engagement, as schematically shown in FIG. 4. The lens 10 is then in a position which as faithfully as possible duplicates the position of the original natural lens, prior to its development of the cataract condition which dictated its removal. It follows that the patient will achieve maximum reinstatement of his original vision capabilities, including a wide angle of peripheral perception.

FIG. 5 illustrates that the described structure of FIGS. 1 to 3 may alternatively be used to implant lens 10 more forwardly of the position described for FIG. 4 but nevertheless fully contained within the sac 113, the difference being that the feet 111 compliantly engage the sac wall in the direction rearward of the plane of support of lens 10. To operatively achieve such mounting, a single releasable filament through all slots 112 again draws feet 111 inwardly to develop transient overall size reduction (overall size being then essentially the outer diameter D.sub.4 of body 13), but the manipulative tool so engages the lens that the in-drawn feet 111 are first to enter the sac 13. Once lens 10 enters the sac, the filament is withdrawn, to release feet 111 to their FIG. 5 positions of engagement with the sac wall.

FIGS. 6 and 7 illustrate mounting structure providing sac-engageable feet as in FIG. 1, but without the need for hook-and-slot formations. In the form of FIG. 6, the mount comprises two parts A-B, each having four equally spaced legs 111a-111b as described for the legs 111 of FIG. 2. The parts A-B may be identical and are differentiated in FIG. 6 by shading of part B to the exclusion of part A. Each of parts A and B has a circumferentially continuous annular body 30 which laps a different side of the rim of lens 10, and the bodies 30 are laminated to each other, as by suitable ultrasonic-welding, heat-bonding or cementing techniques, in the region of their registering overlap radially outside the rim of lens 10. The parts A-B are assembled with their bodies 10 in registration but with their feet 111a-111b in angularly staggered interlace. Plural registering spaced arcuate slots 31 outside the lens-rim diameter D.sub.2 are preferably located between regions of connection of feet 111a-111b to the registering bodies 30, to facilitate body lamination and enhance lens retention. The resulting product provides the security of a circumferentially continuous laminated body of double thickness, while avoiding the stiffness that would result from laminating feet 111a-111b to each other. In other words, the single-thickness nature of feet 111a-111b renders them weakly compliant, for the ready flexing which is required in the described operative procedures.

The arrangement of FIG. 7 will be recognized for its similarity to FIG. 6, except that the mounting parts A'-B' of FIG. 7 are expressly not duplicates of each other, in that all eight foot formations 111c (being shaded) are integrally formed with the part B', while the part A' is a simple body ring 30'. Registering body slots 31 again enable secure lamination of parts A'-B' and accurate retention of lens 10 by engagement with opposite sides of its rim.

The described body-member configurations and assemblies will be seen to utilize basic two-part lens-mounting structures which are to an extent modular, in that a wide variety of different anterior and posterior suspensions can be provided, to suit the professional preference or decision of the surgeon. Of course, the surgeon will have specified the lens properties appropriate to the ultimate axial location at which he intends to make his implant. In all cases, finish-ground optical quality glass is preferred at lenses 10, generally of 5 mm diameter and 0.3 mm thickness, although if tolerated by the body preformed plastic lenses may be used.

Reference has been made to thin-sheet compliant flexible material for the described mounting structure. This represents my preference, and I indicate my further preference to employ a stable, strong, flexible polyimide, selected for commercial availability and autoclavability. The precise formation of described blank configurations is preferably achieved through photolithographic techniques which are described in one or more of the patent disclosures referred to in my said patent. With all presently described forms, thickness of the flexible sheet material is desirably in the range 0.0005 to 0.002 inch, preferably 0.001 inch, at least for the part or parts which embody the compliant feet 111, 111a, 111b, 111c; for a plain ring, as at 12 or A', the 0.002-inch thickness is preferable.

The described structures will be seen to achieve all stated objects and to provide an improved product suited to particular needs, and especially adaptable to quantity production through use of identical lithographically fabricated body blanks on a single sheet. And, the ability to mount the lens independent of relying upon the iris for stabilization, is also expected to materially reduce the likelihood of trauma due to implantation.

While the invention has been described in detail for the preferred forms shown, it will be understood that modifications may be made without departing from the claimed invention.