ARTIFICIAL LENS

Abstract: Disclosed is an artifical lens adapted for implantation in the human eye and the method for implanting such lens. The lens (1) is of pliable material so that it may be folded or curled for insertion through a minimum length incision. It has a medial optic portion (2) having a posterior concave surface (2a) corresponding to the anterior surface (13c) of the natural lens (13) when the latter is in its flattest natural position and haptic portions (3, 4) for seating the lens in the eye such that the posterior concave surface of the medial optic portion of the artificial lens seats directly against the anterior surface of the natural lens of the eye which remains in and is not removed from the eye. The method according to the invention includes determining the shape of the anterior surface of the natural lens when the latter is in its flattest natural position, forming the posterior surface of the optic of the artificial lens such as to correspond substantially to that shape and seating the lens in the posterior chamber between the iris and the natural lens with the posterior concave surface of the artificial lens seated on the anterior convex surface of the natural lens.

Description: FIELD AND BACKGROUND OF THE INVENTION The present invention relates to an artificial lens for implanting in the eye to cooperate with the natural lens for correcting the eyesight of the eye in question. The natural lens in the human eye is deformable and attached at its periphery by zonules which allow the biconvex natural lens to be deformed from a first condition in which the lens is flattest (i.e., non-accommodating), to a second condition in which the natural lens is more convex than in said first condition. Thus, the normal, healthy natural lens can conform to the optical power which is required. In those cases where the natural lens does not properly accommodate to achieve the desired vision, or in other cases where the length of the eyeball is such that the image from a healthy lens falls short of, or behind the retina, spectacles or contact lenses are required to compensate for the deficiency of the natural lens or axial length. Such external devices are cumbersome, particularly in cases of high degree of myopia where the external lenses have to be quite thick in order to adequately compensate. Spectacles have the disadvantages that they are often uncomfortable to wear, can fall off and break and are frequently perceived as marring the appearance of the wearer. Contact lenses, on the other hand, cannot be tolerated by everyone and even those who can tolerate such lenses face well known problems associated therewith. For example, the necessity to maintain the lenses absolutely clean, difficulties in removing and inserting the lenses, occasional unpleasant irritation as a result of wearing the contact lenses, possible infection and, on occasion, losing a lens. US-A-4,585,456 discloses an artificial lens implant for correcting the eyesight of a human eye, comprising a medial optic portion of pliable material having a concave posterior face adapted to seat on the anterior surface of the natural lens in the eye, said optic portion having an anterior face of such shape that the combined effect of said anterior and posterior faces of said optic portion is to provide the appropriate optical power required for correcting the eyesight of the eye in question, and seating means comprising a pair of opposed seating portions extending in generally opposite directions from said medial optic portion, for seating the lens in the eye in such position that said medial optic portion will be seated on the natural lens in the eye, said seating portions of the lens being adapted to seat in opposite grooved portions, respectively, of the eye, formed between the iris and the zonules thereof. This US patent does not discuss the problem of slipping between the lens implant and the natural lens. The artificial lens implant of the present invention is characterised in that seating means are each inclined with respect to a plane perpendicular to the optical axis of the medial optic portion and passing centrally through that portion, the inclination being away from the concave posterior face of the medial optic portion. A lens implant is provided which may be inserted into the eye through a relatively small incision and will thereafter cooperate with the natural lens. Ready correction is possible of myopia of varying degree, including high degrees of myopia. By varying the shape of the anterior surface of the implant, such implant can also be used to correct hyperopia. The necessary surgical procedure does not involve removal of the natural lens or reshaping of the cornea, and can readily be adopted by surgeons experienced in the implantation of intraocular lenses. BRIEF DESCRIPTION OF THE DRAWINGS Other and further objects and advantages of the present invention will become apparent from the within specification and accompanying drawings, in which: Figure 1 is an enlarged front elevational view of the intraocular lens according to one embodiment of the present invention; Figure 2 is a cross-sectional view taken along the line 2-2 of figure 1; Figure 3 is an enlarged schematic cross-sectional partial view of a human eye showing the intraocular lens of figures 1 and 2 seated therein, with the pupil dilated and the natural lens in its flattest condition thereof; Figure 4 is an enlarged schematic cross-sectional partial view of a human eye showing the intraocular lens of figures 1 and 2 seated therein, with the pupil contracted and the natural lens in its most convex condition; Figure 5 is an enlarged cross-sectional view of a lens according to another embodiment of the present invention; and Figure 6 is an enlarged cross-sectional view of a lens according to still another embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, and initially to figures 1 and 2, an intraocular lens according to one embodiment of the present invention is shown, which is usable for implantation in the human eye between the iris and the natural lens in the eye, without removing the natural lens. Lens 1 comprises a central optic portion 2 and a pair of preferably generally flat haptic portions 3 and 4 extending in opposite directions from opposite peripheral portions of the optic 2. The haptic portions 3, 4 have distal seating portions 5 and 6, respectively, each having a pair of spaced rounded seating projections 5a, 5b and 6a, 6b, respectively separated preferably by intermediate concave portions 5c and 6c, respectively. Preferably, the flat haptic portions 3 and 4 are slightly inclined, as best seen in figure 2, with respect to a central plane P of the optic portion 2. Such inclination may be approximately of the order of 10 or 15 degrees. The rounded seating projections 5a, 5b and 6a, 6b provide four-point seating for the lens and are preferably formed so as to provide minimum contact surface with the eye tissue which the lens contacts when seated, and the aforesaid angle of inclination is preferably chosen such as to maintain the intraocular lens seated on the natural lens, as will be explained below, after the haptics 3 and 4 of the intraocular lens are seated in the eye. Optic portion 2 is formed with a concave posterior surface 2a and preferably has a convex anterior surface 2b, as best seen in figure 2. It will be noted, however, that the optic portion 2 may be, according to another embodiment of the present invention, formed with a planar anterior surface 2c, such as seen in figure 5, or a concave anterior surface 2d, as, for example, the embodiment illustrated in figure 6. In each instance, however, the concave configuration of the posterior surface will be such as to correspond substantially to the anterior surface of the natural lens in the eye when the latter is in its flattest, i.e, non-accommodating condition. Thus, as may be seen in figure 3, the lens 1 according to one embodiment of the present invention is seated in the ciliary sulcus 10 formed between the iris 11 and the zonules 12 which support the natural lens 13 of the eye 14. Preferably, the lens 1 according to the invention is formed of silicone or other similar pliable material and may be folded, for example, along its longitudinal center line C, seen in figure 1, or may be curled generally about said longitudinal center line, for forming a cylinder no more than about 3 mm in diameter, and approximately 13 mm in length (representing the longitudinal length of the lens 1). Optic 2 is preferably about 6 mm in diameter and has a maximum thickness, i.e., measured along the optical axis, of about 2 mm. The haptics 3 and 4 preferably have a width of about 6 mm and a thickness of about 1 mm. Inasmuch as the entire lens is formed of pliable material and because of the concave shape of the posterior surface 2a thereof and the relatively thin haptics, the lens 1 may be readily folded or curled along its longitudinal center line C into, for example, the aforesaid cylindrical shape which will fit through a minimum length incision 15 in the cornea 16 of the eye to minimize trauma associated with the required surgery surgery. Preferably, during such surgery, a visco-elastic substance, such as Healon (registered trade mark) is used to temporarily maintain the anterior chamber 17 in expanded condition. At such time, the artificial lens according to this invention is inserted in curled or folded condition, through the incision 15, into the anterior chamber and the inferior portion of the lens 1 is passed through the pupil 18 and seated behind the iris 11 in the inferior portion of groove 10 formed between the iris and the zonules supporting the natural lens 13, which remains in the eye Thereafter, the superior portion of the artificial lens is passed through the pupil 18 and seated in the superior portion of the same groove 10. Consequently, the artificial lens 1 will be positioned between the iris 11 and the natural lens 13 with the posterior concave surface 2a of the optic 2, in substantial surface-to-surface contact with the anterior surface 13a of the natural lens 13. Prior to such insertion and seating, the desired shape of the concave posterior surface 2a of the lens 1 is determined by measuring the shape of convex anterior surface 13a of the natural lens of the eye to determine the exact configuration thereof. Such determination may be made by means well-known to those skilled in the art as, for example, the use of ultra-sonography using a "B" scan or an "A" scan. Once that determination is made, the surgeon will either choose, from an inventory of lenses that lens which has a posterior concave surface configuration most closely resembling the mirror image of the convex anterior surface of the natural lens, or will have a lens ground, or otherwise formed, to the desired configuration. Such configuration will be determined with the natural lens in its flattest, ie., non-accommodating, condition. The anterior surface of the optic of the artificial lens will be formed to such configuration as will correct the eyesight desired to be corrected. This determination will be based on a measurement of the corrective power of the natural lens in the eye and determining the curvature of the anterior surface of the optic of the artificial lens which, when cooperating with the natural lens, will provide the proper corrective power for the eye in question. The seating of the artificial lens 1 on the natural lens 13 is such that surfaces 2a and 13a will be in substantial surface to surface contact with one another without a space therebetween, when the natural lens 13 is in its flattest, i.e., non-accommodating condition. As previously noted, the inclination of the haptic portions 3 and 4 is such that the optic 2 will be urged thereby toward and into such seating engagement with the surface 13a of the natural lens. Figure 4 illustrates the relationship between the artificial lens 1 and the natural lens 13 after the natural lens has assumed its most convex condition. It will be seen that in this condition of the natural lens only the central portion of the concave posterior surface of the optic 2 remains in seating contact with the surface 13a, while the peripheral portions of the concave posterior surface of the optic may be slightly spaced from the natural lens due to the more convex shape of natural lens surface 13a. Still, however, the arrangement is such that, even in this condition, the iris, (shown in figure 4 with the pupil contracted) will be able to function normally without substantial impediment. In this connection it should be noted that it has been found that eyes exhibiting a high degree of myopia, for example, are usually enlarged and have somewhat enlarged spaces between the elements thereof, such as between the natural lens and the iris so as to provide sufficient room for the optic 2 to be positioned therebetween. It will be seen that while the lens 1 of figures 1 to 4, is particularly suitable for correcting the eyesight of persons suffering from myopia, including those suffering from a high degree of myopia, the lens according to the embodiment generally illustrated in figure 6 is capable of correcting the eyesight of persons suffering from hyperopia. Thus, the plano-concave optic of the figure 5 embodiment and the concavo-concave optic of the figure 6 embodiment, represent variations of the lens according to the present invention. In each case, however, the optic will have a concave posterior surface for seating engagement with the anterior surface of the natural lens of the eye. It will be understood, of course, that any means may be employed to measure the shape of the convex anterior surface of the natural lens in the eye and similarly that any one of many well-known means may be used to measure the optical power required for correcting the eyesight of the eye in question. Those skilled in the art are familiar with apparatus and techniques for making these measurements. It will also be understood that the lens according to the present invention, while preferably formed of a single piece of silicone or similarly pliable material, may have its central optic portion formed of one such material and its haptic portions formed of another material suitably connected thereto.

Claims: An artificial lens implant (1) for correcting the eyesight of human eye, comprising: (a) a medial optic portion (2) of pliable material having a concave posterior face (2a) which is (i) adapted to seat on the anterior surface (13a) of the natural lens in the eye, and (ii) shaped to conform to, and to make face-to-face contact with, the convex shape of the anterior surface of the natural lens (13) when the natural lens is at or towards its flattest natural condition, so that face-to-face contact between central portions of the posterior face (2a) of the medial optic portion (2) and the anterior surface (13a) of the natural lens (13) is always maintained, the optic portion (2) having an anterior face (2b) of such shape that the combined effect of the anterior and posterior faces of the optic portion is to provide the appropriate optical power require for correcting the eyesight of the eye in question, and (b) seating means comprising a pair of opposed seating portions (3,4) extending in generally opposite directions from the medial optic portion, for seating the lens in the eye in such position that the medial optic portion will be seated on the natural lens in the eye, the seating portions of the lens being adapted to seat in opposite grooved portions (10), respectively, of the eye, formed between the iris (11) and the zonules (12) thereof. characterised in that the seating means (3,4) are each inclined with respect to a plane (P) perpendicular to the optical axis of the medial optic portion (2) and passing centrally through that portion, the inclination being away from the concave posterior face (2a) of the medial optic portion. A lens according to claim 1 or claim 2, characterised in that each seating portion (3,4) comprises a pair of spaced outwardly extending contact points (5a, 5b and 6a,6b respectively) for fixating the lens in the eye. A lens according to any one of the preceding claims characterised in that said lens is generally rectangular in shape and said seating means are a pair of sheet portions (3,4) extending in diametrically opposed directions from said medial optic portion. A lens according to any one of the preceding claims, characterised in that the material of said medial optic portion (2) is silicone. A lens according to claim 4 characterised in that said optic portion (2) and said seating means (3,4) are formed of a single piece of silicone. A lens according to any one of the preceding claims, characterised in that said anterior face (2b) of said medial optic portion is convex. A lens according to any one of claims 1 to 5, characterised in that said anterior face (2b) of said medial optic portion (2) is planar. A lens according to any one of claims 1 to 5, characterised in that said anterior face (2b) of said medial optic portion (2) is concave.

Inventors: kELMAN, CHARLES D.
Applicants: kELMAN, CHARLES D.
Application year: 1988
Main classification: A61F2
IPC codes: A61F2