Intraocular Lens Construction

Said application discloses a variety of intraocular-lens constructions featuring different kinds of haptic for specific different types and locations of implantation in a human eye; and the present invention relates particularly to that variety which is adapted for trans-iris manipulation and installation.

Reference is made to said copending application for a more full statement of the background of the invention.

It is an object of the invention to provide an improved intraocular lens and associated haptic of the character indicated.

Another object is to provide such structure with improved features adapting the same for trans-iris manipulation and implantation.

A further object is to meet the above object with a configuration from which a uniquely identifiable orientation can be readily recognized by the surgeon making an intraocular implantation.

The foregoing and other objects and features are realized in a variety of flexible haptic structures wherein two asymmetrically defined, generally diametrically opposed stabilizing feet extend radially outward of the region of lens retention and which are each characterized by an arcuate peripheral band adapted for positioning engagement with structural features within the posterior chamber of the eye. Loop formations local to a single peripheral band and to the region of lens retention define localized openings adapted for reception of suture, pincer or other means.

The invention will be described in detail for various embodiments, in conjunction with the accompanying drawings, in which:

FIG. 1 is a view in elevation, showing an intraocular lens and haptic assembly of the invention;

FIG. 2 is a side view of the assembly of FIG. 1;

FIG. 3 is a plan view of the blank of one of the haptic parts of FIG. 1;

FIG. 4 is a plan view of the blank of the other of the haptic parts of FIG. 1; and

FIGS. 5, 6 and 7 are views similar to FIG. 3 to show different embodiments.

In FIGS. 1 and 2, the invention is shown in application to an intraocular-lens assembly wherein an optically finished circular lens 10 is retained at its periphery by haptic or mounting-adapter structure comprising two parts A and B, each of which is separately shown, at FIGS. 3 and 4, respectively. The lens 10 is preferably of optically finished glass, with a periphery of 5-mm diameter (D.sub.1); its maximum thickness T.sub.1 will vary with prescription power, but such thickness is typically about 0.3-mm. Each of the haptic parts A (B) is of flexible plastic sheet material and is characterized by an annular body 11 (11') of inside diameter D.sub.2 slightly less than D.sub.1, to permit circumferentially continuous retaining overlap with opposite axial sides of the periphery of lens 10, when in coaxial register. The outer diameter D.sub.3 of each annular body 11 (11') exceeds D.sub.1 by an amount which accommodates interlocking diametrically opposed pairs of arcuate hook formations, as at 12-13 (12'-13') on one part A (B) to interlockingly engage diametrically opposed arcuate slot formations, as at 14' (14) on the other part B (A), the slot formations in each case being in quadrant interlace with the pairs of hook formations. Such formations and their interlocking are not part of the present invention, and reference is made to said copending application for more complete description thereof. The material of the haptic parts is flexible and autoclavable, being suitably a polyimide of thickness T.sub.2 which may be in the range 0.05 to 0.10-mm.

In accordance with a feature of the invention, asymmetrical position-stabilizing feet 15-16 extend generally radially outward of the interlocked annular bodies 11-11' at generally diametrically opposed locations, and these feet 15-16 are integral formations of the part A alone. In the form of FIG. 1, the foot 15 is relatively stiff radially, while the foot 16 has relatively compliant radial connection to body 11. More specifically, the foot 15 is seen to comprise a generally arcuate band 17 of width W.sub.1 and conforming generally to a geometrical circle having the maximum diametral span D.sub.4 of part A; band 17 is integrally connected to body 11 via two outer-end legs 18-19 and via an intermediate radial leg 20. The foot 16 also comprises a generally arcuate band 21 which (when implanted) conforms generally and compliantly to the geometrical circle of diameter D.sub.4, but its width W.sub.2 is substantially less than W.sub.1 ; in its unstressed state, the outer band 21 projects slightly outside the circle of diameter D.sub.4 (as shown in solid outline in FIGS. 1 and 3), and when installed its compliantly deformed shape is as shown in phantom outline 21'. Radially compliant action derives from a single generally radial leg 22 (shown slotted for greater compliance) which integrally connects one end of band 21 to body 11, further radially compliant action being provided by a radially inward undulation 23 at the mid-section of band 21. A first loop formation 24 characterizes the connection of leg 20 to body 11; a second loop formation 25 is integrally formed with body 11 at a location diametrically opposed to formation 24, and a third such formation 26 is at the other angular end of the arcuate band 21. The loop formations 24-25-26 define localized circular openings of about 0.5-mm diameter, for reception of suture, pincer or other manipulating means.

When the diametral span D.sub.4 is about 13-mm, depending upon internal dimensions of the posterior chamber of a particular human eye, the described lens 10 and haptic structure A-B assembled thereto is particularly suited for trans-iris operative implantation in the posterior chamber with the arcuate bands 17-21 deriving stabilizing support within the ciliary sulcus, thus placing lens 10 coaxial with the iris-to-fundus alignment and just posterior to the iris. In other words, there need be no reliance upon the iris for haptic or lens support or engagement, so that normal iris action is unimpeded, and the likelihood of related trauma is reduced to insignificance.

Various procedural options are available to the surgeon who elects to implant the assembly of FIG. 2, once he has removed all cataracted material. In one illustrative technique, he may employ a releasably tied suture filament between loops 24-26 to transiently deform foot 16 over a face of lens 10 while using a pincer hold on bodies 11-11' at the region 25, during trans-iris manipulation of foot 15 and then bodies 11-11' (and lens 10) through a dilated iris, to the point of initial band (17) contact with a local region of the ciliary sulcus. The pincer hold at region 25 is now also within the posterior chamber, and the suture retraction of foot 16 has enabled such placement with little or no interference via foot 16. The tie of suture is now released, and the suture withdrawn, thus enabling the compliant nature of foot 16 to restore itself to the phantom shape indicated in FIG. 1, namely, with posterior chamber contact and support diametrically opposed to the contact and support at 17. When satisfied that all is in desired position and angular orientation, the pincers are released and withdrawn, the operation otherwise proceeding to completion in normal fashion.

In an alternative procedure, no suture filament is required. A pincer-point insertion through loop 26 provides sufficient engagement to enable pincer-manipulated twisting of foot 16 back over a face of lens 10 prior to establishing further pincer engagement with bodies 11-11' at the region 25. Trans-iris manipulation to the point of initial band (17) contact within the ciliary sulcus is then as described above, again with little or no interference via foot 16. The pincer hold is released when the surgeon is satisfied with orientation of the initial placement, thus allowing compliant restoration of foot 16 to its stabilizing contact within the ciliary sulcus. Regardless of the technique used to achieve trans-iris posterior-chamber positioning, the loops 24-25 remain generally accessible for manipulative engagement, should further minor adjustment be deemed necessary, for correct implant positioning.

The embodiment of FIG. 5 will be seen to employ a haptic part A' in substitution of the part A of FIG. 2, lens 10 being then retained by the plural hook-and-slot engagements of part A' with those of part B. Part A' is again characterized by diametrically opposed asymmetrical feet 15-16', the arcuate band 27 of foot 16' having connection to body 11 via spaced parallel legs 28-29, and the geometric centerline 30 between legs 28-29 being radial and diametrically opposite the center leg 20 of foot 15. The third loop formation 26' is integral with the inner edge of arcuate band 27.

Manipulation and use of the FIG. 5 embodiment is as described for FIG. 2. In the event of a releasable suture filament, the tie is between loops 24-26', to hold a folded leg 16' across a face of lens 10, pincer grip and manipulation being again at the region 25. In the event of no suture filament, initial pincer engagement at loop 26' enables folded reversal of foot 16' across part of a face of lens 10, with subsequent further pincer grip at the region 25, and the pincer grip is released after the described trans-iris manipulative steps have been performed.

The arrangements of FIGS. 6 and 7 will be recognized for resemblance to FIGS. 1 (3) and 5, respectively, the difference being that the maximum diametral span D.sub.5 is less than D.sub.4. The lesser span D.sub.5 enables intraocular-lens assemblies utilizing parts A" (FIG. 6) and A''' (FIG. 7) to be implanted within and to have stabilizing contact with the inner surface of a lens capsule from which cataracted material has been removed.

Dimensional legends have been applied to show commonality of general dimensions, subject to small variations which are found to characterize particular individuals. The larger width W.sub.1 for the relatively stiff foot 15 (35) is preferably substantially the diametral extent D.sub.3 of bodies 11-11', namely 6 to 6.5-mm, and the smaller width W.sub.2 is substantially less (approximately 4.0-mm) so that when transiently folded, as described, there will assuredly be no accompanying projections of the folded foot 16 (16'-36-36') outside the outer limit of bodies 11-11'.

The described structures will be seen to have achieved all stated objects. In particular, the asymmetrical haptic configurations enable instant recognition of a reference orientation, for deliberate and correct orientation of the complete assembly in an eye, and depending upon the surgeon's predetermination of his desired ultimate orientation, whereby a lens 10 having a prescription grinding to correct for a diagnosed astigmatism error and correctly oriented for such correction in reference to the haptic asymmetry may be correctly implanted to achieve the desired correction; such techniques are explained in greater detail in my copending application Ser. No. 132,275, filed Mar. 20, 1980. The asymmetry is also seen to lend itself favorably to the mechanical problems of trans-iris implantation, whether or not releasable suture filament is employed.

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