Bifocal Intraocular Lens Structure and Spectacle Actuation Frame

The invention relates to intraocular lens structures, that is, to structures designed and adapted for surgical implantation in an eye, in place of a cataracted natural lens.

Surgical implantation of an artificial lens, in place of a cataracted natural lens, is rapidly becoming an accepted procedure, offering the user the advantage of wide-angle vision and avoidance of the cumbersome strong-lens spectacles that have traditionally been the burden for those who have had a cataract removed. The surgeon has a great variety of lens-implant styles from which to chose, but to my knowledge all such lens-implants to date contemplate but a single focal length of the implant. It is therefore necessary for the user to provide himself with such spectacles as may enable him to correct his vision for any range outside the capability of his fixed-focus implant.

It is an object of the invention to provide improved intraocular lens structure enabling multiple-focus operation within the eye.

A specific object is to provide structure enabling implantation of at least two lenses within a given eye, with selective availability of one to the exclusion of the other of said lenses, to achieve different focal circumstances appropriate to different ranges of desired-object viewing.

Another specific object is to provide structure enabling implantation of an intraocular optical element which is selectively movable into and out of the viewing or pupillary axis of the eye.

A further specific object is to provide externally operable actuator means for selectively positioning an installed intraocular lens into and out of the optical axis of the eye.

A general object is to achieve the above object with relatively simple and low-mass structure which can be surgically manipulated and correctly installed, using present techniques.

The invention achieves the foregoing objects and certain further features by providing haptic-supported frame structure for stabilized mounting in one of the chambers of an eye, and an auxiliary lens or other optical element has movably guided coaction with the frame structure, whereby in one selectively available position the auxiliary element is substantially aligned with the viewing axis of the eye, and in another selectively available position the auxiliary element is substantially out of the bundle of rays used for normal viewing. In the forms to be described, the movable auxiliary element is pivotally suspended and is magnetically actuable from one to the other of its two possible positions. And the forms to be described illustrate various combinations with posterior-chamber mounting, anterior-chamber mounting and trans-iris mounting of the movable element.

The invention will be illustratively described in detail, in conjunction with the accompanying drawings, in which:

FIG. 1 is a front-elevation view of intraocular lens structure of the invention;

FIG. 2 is a side-elevation view of the structure of FIG. 1, certain parts being partly broken-away and in vertical section, generally along the line 2-2 of FIG. 1;

FIGS. 3, 4 and 5 are views taken at successive optical-axis locations in the structure of FIGS. 1 and 2, namely, as indicated at 3-3, 4-4 and 5-5, respectively, in FIG. 2;

FIGS. 6 and 7 are views corresponding to FIGS. 1 and 2 to illustrate another embodiment, the section plane of FIG. 7 being generally at the line 7-7 of FIG. 6;

FIGS. 8 and 9 are views also corresponding to FIGS. 1 and 2, but illustrating a third embodiment, the section plane of FIG. 9 being generally at the line 9-9 of FIG. 8;

FIGS. 10 and 11 are further views corresponding to FIGS. 1 and 2, to illustrate a fourth embodiment, the section plane of FIG. 11 being generally at the line 11-11 of FIG. 10; and

FIGS. 12 and 13 are simplified views in perspective to illustrate a non-invasive actuating means for intraocular implants as described for the various embodiments.

Referring initially to FIGS. 1 to 5, the invention is shown in application to a conventional intraocular lens 10 having compliant haptic formations 11-11' adapted particularly for stabilizing contact with the inner wall of the posterior chamber of an eye. The lens 10 may be molded, turned and polished plastic, inert to body fluids, methyl methacrylate being acceptably usable, and the haptic elements may suitably be of polypropylene. Surgical implantation procedure for posterior lens 10 and its haptics may be conventional, via a dilated iris, as will be understood.

In accordance with a feature of the invention, a second optical element, such as another lens 12, is movably supported with respect to the relatively fixed structure of posterior lens 10 and its haptics. More specifically, a frame member 13, which provides pivotal reference for movable lens 12, has a central opening 14 deriving axially forward cantilevered support from the posterior lens 10 via plural trans-iris posts 15, equally spaced about the optical axis Y of lens 10. The forward offset provided by posts 15 will be understood to be sufficient to position frame member 13 within the anterior chamber and with sufficient relief from the iris to allow normal mobility of the iris, i.e., normal dilation with respect to its constricted condition, suggested by phantom outline 16 in FIG. 3.

The movable lens element 12 may be of material and finish as described for lens 10, and it is shown with an integrally formed pivot arm 17 and with a pivot pin 18 engaged in a suitable bearing aperture in frame member 13. A second frame member 20 with a central aperture 21 is connected to frame member 13 via spaced lugs 22-23-24, and in such forwardly offset relation to member 13 as to establish positively guided retention of movable lens 12 by and between frame members 13-20, the opposite ends of pivot pin 18 being located in bearing apertures, as at 25 in frame member 20. It is convenient to provide a laterally extending formation 26 in frame member 13, and 27 in frame member 20, so that lugs 23-24 may connect members 13-20 on opposite sides of the pivot axis and so that lug 24 may serve as a stop, to locate the off-axis position of movable lens 12, as best seen in FIG. 4.

In its off-axis position, the optical axis X of movable lens 12 is preferably at the horizontal elevation of the optical axis Y of lens 10, and preferably also, the axis of pivot 18 is below and on the perpendicular bisector of the geometrical line between X and Y, as seen in FIG. 4. Further, the offset of pivot 18 below the line between X and Y may suitably be such that lens element 12 moves about 90 degrees between its off-axis position (FIG. 4) and its on-axis position of axial alignment with the optical axis Y of the fixed lens element 10. And it will be understood that lugs 22-23 cooperate with movable lens element 12 in its on-axis position, serving as limiting stops. By locating the pivot axis as indicated, and by installing the implant with X and Y on a horizontally oriented alignment, the stop 24 arrests normal gravitational descent of lens 12 to serve as a means of retaining the off-axis position (FIG. 4), while stop 23 arrests normal gravitational descent of lens 12 (on the other side of pivot 18) to serve as a means of retaining the on-axis position of axial alignment of the two lenses 10-12.

Description of the embodiment of FIGS. 1 to 5 is completed by identifying ear projections 28 at spaced locations around movable lens 12, to assure total axial capture of lens 12 by and between rims 14-21 of frame members 13-20 when in the on-axis position. Also, for remote-actuation purposes, a paramagnetic insert 30 is embedded in the material of lens element 12 at greatest radial offset from pivot 18. It will be understood that a permanent magnet (not shown) but embodied for example in a finger ring of the wearer of the structure of FIGS. 1 to 5 may serve to non-invasively actuate the movable lens element 12; he need only draw his magnetic ring across his eyebrow in a desired direction, in order to dislodge movable lens element 12 from one of its two positions and to move it to the other of its two positions.

The embodiment of FIGS. 6 and 7 illustrates application of the invention to an anterior-chamber mounting. In particular, an anterior-chamber "fixed", lens element 40 carries opposed haptic elements 41-11' , with suitably vaulted offset ends for minimal iris contact and allowing total freedom for normal mobility of the iris. Lens element 40 is plano-convex and is preferably oriented with its plane surface facing forward, in close adjacency with the plane surface of a movable lens element 42 having arm and pivot formations 17-18 as described for lens element 12 (FIGS. 1 to 5). A bearing aperture 43 in lens 40 mounts one end of pivot 18, and a bearing aperture in a frame member 44 mounts the other end of pivot 18. Spacer posts or lugs 45-46-47 retain the central opening 48 of frame member 44 in register with the optical axis of lens 49 and serve as limit stops for the respective off-axis and on-axis positions of movable lens element 42, analogous to similar functions described for the embodiment of FIGS. 1 to 5. Ears 28 on lens element 42 retain the axially-captured status when in the on-axis position, and magnetic element 30 in movable lens 42 enables selective surgically non-invasive actuation from one to the other of the two limiting positions of lens 42.

The embodiment of FIGS. 8 and 9 is very much like that of FIGS. 6 and 7, except that in place of the fixed lens 40 is a fixed frame member 49 which is equipped by haptic means 41-41' and which may otherwise be generally as described for frame member 13 of FIG. 4, i.e., with a central circular opening 14, with a lateral arm projection 26, and with spaced connecting lugs 22-23-24 for positioning a second frame member 20 of the nature shown in FIG. 5; for clarity, frame member 20 is shown in FIG. 9 but has been omitted from FIG. 8. The movable lens element 42 of FIGS. 8 and 9 is guided by and between frame members 20-49 and is non-invasively actuated via an imbedded magnetic element 30. It will be appreciated that the embodiment of FIGS. 8 and 9 may serve the patient who already has a posterior-chamber implanted lens (as, for example, shown in FIG. 3 but without posts 15) and for whom it is desired to provide selectably extendable focal range, by reason of anterior-chamber implantation of the device of FIGS. 8 and 9, with opening 14 centered on the pupillary axis Y.

The embodiment of FIGS. 10 and 11 exemplifies the invention in application to anterior-chamber mounting, of a frame member 60 via vaulted haptics 61-61' with reference to the stationary or scleral-ridge region of the anterior-chamber side of the iris. A movable lens element 62 includes a pivot pin 63 which derives bearing support from aligned apertures in frame member 60 and in an outer frame member 64, frame members 60-64 being held in axially spaced register by spacer posts or lugs 65-66-67. A "fixed" posterior lens element 68 derives axially aligned cantilevered support from frame member 60, via angularly spaced trans-iris positioning struts 69. Each of the struts will be understood to be L-shaped, with a radially inward leg portion anchored to frame member 60, and with an axially inward trans-iris portion anchored to lens element 68. Outward ear projections 70-71 on movable lens element 62 will be understood to axially restrain the on-axis position of element 62. The on-axis angular position is retained by a stop lug or pin 72 on one of the frame members 60-64, and the off-axis position is retained by lug 67, as will be understood.

While it has been indicated that actuating structure for the described movable-lens configurations may be as simple as a polarized magnet embodied in a finger ring, it may to some users be more convenient to embody magnetic control in a spectacle frame, whether or not there are optical lens elements fitted to the spectacle frame. Such structure and its operation are shown in the simplified views of FIGS. 12 and 13. In FIG. 12, a spectacle frame is seen to comprise a transverse member 80, with hinged ear pieces 81-81' at its ends; a suitably shaped central bridge formation 82 is comfortably adapted to the nose, and optional lens elements are suggested by phantom outlines 83-84. In accordance with a feature of the invention, polarized magnets 85-86 are reversibly mounted to the spectacle frame, being shown pivotally mounted near the ends of member 80, and preferably a third such magnet 87 is similarly mounted in the bridge region of member 80. These magnets may be of any suitable shape, for example pinion-shaped and polarized along a diameter, but for schematic purposes these magnets are shown as bars, with pinion teeth, and polarized as suggested by N-S symbolism. A shiftable member 88 with rack teeth engaged to magnet-pinion teeth has an exposed actuable element 89 for selecting either the polarity relation shown or a 180.degree.-reversed polarity configuration, as will be understood.

The described spectacle frame with reversible magnets is shown in FIG. 13 to effect desired actuation of movable-lens elements 12 (in one eye's intraocular implantation) and 12' (in the other eye's intraocular implantation). In the left-eye implantation, the on-axis position of movable-lens axis X registration with fixed-lens axis Y is inward, toward the nose, and the off-axis position is outward, toward the adjacent ear piece 81; and in the right-eye implantation, the on-axis position of movable-lens axis X' registration with fixed-lens axis Y' is inward, toward the nose, the off-axis position being outward toward ear piece 81' and, therefore, in the displacement direction away from off-axis displacement of lens axis X for the left eye. Magnet inserts 30 in the respective movable-lens elements 12-12' are polarized alike, as shown by N-S symbolism, the axis of polarization being transverse of the central line of symmetry of each element 12-12' , i.e., through its pivot center 18 and the center of its magnet insert 30.

For the described configuration of insert 30 polarization and of off-axis to on-axis displacements for movable lens elements 12-12' , the polarized orientation of outer magnets 85-86 should always be opposed to that of the central magnet 87. That being the case, for the relation shown in FIG. 13, the off-axis or outward-left position of lens element 12 is magnetically retained by proximity of the North-polarized end of magnet 85 and the South-polarized end of the involved insert 30. At the same time, the off-axis or outward-right position of lens element 12' is magnetically retained by proximity of the South-polarized end of magnet 86 and the North-polarized end of the involved insert 30. Also at the same time, the orientation of central magnet 87 is such as to present like poles to the nearest poles of elements 30, thus developing repel action for further assured retention of the off-axis positions of both movable lens elements 12-12' .

When it is desired to bring both movable lens elements into their on-axis positions of registration with the respective pupillary axes Y-Y' , the shift device 89 is manually displaced, causing magnets 85-86-87 to 180.degree.-reverse their polarized orientation. In this circumstance, like adjacent poles (the South poles of magnet 85 and the nearby insert 30) repel to develop clockwise torque about the pivot axis of movable element 12, resulting in its left-to-right displacement into the on-axis position of registration with axis Y; and upon reaching this on-axis position, the attraction of opposite poles at 30 and 87 serves to retain the on-axis position of element 12. In similar fashion and concurrently, like adjacent poles (the North poles of magnet 86 and of nearby insert 30) repel to develop counterclockwise torque about the pivot axis of movable element 12', resulting in its right-to-left displacement into the on-axis position of registration with axis Y'.

Subsequent return of actuator 89 to the position shown returns all rotatable magnets to their orientations shown, and resulting torques on the movable lens elements 12-12' effect concurrent return displacements to and magnetic retention of the respective off-axis positions.

The described invention will be seen to achieve all stated objects with basically simple and lightweight structure. And the principles of the invention are seen to be applicable to varied anterior, posterior, and trans-iris support, to suit the choice of the individual surgeon. The involved implantation technique need be no more difficult or complex than for conventional single-lens implantations. It will, of course, be understood that in the drawings it was necessary to show sizes, thicknesses and clearances with some exaggeration, in order to permit identification of parts; for example, the displacement sweep of lens element 12 from one to the other of its positions is under the continuous guidance not only of the described pivot (18) action but also of surfaces of frame members 13-20 (FIGS. 1 to 5), or of lens 40 and frame member 44 (FIGS. 6, 7), etc.

While the invention has been described in detail for preferred embodiments, it will be understood that modifications may be made without departure from the scope of the invention. For example, guided shifting of movable lens elements may be longitudinal and thus other than via a pivot suspension, and reversible magnet elements in the spectacles may be carried by the ear pieces and be individually shiftable to effect selective reversal of their horizontally polarized directions.