Intraocular Lens

The present invention relates to an intraocular lens structure designed to be seated partly in the anterior and partly in the posterior chamber of the eye after the removal of a natural lens as a result of a cataract condition.

It has been found that the insertion of an intraocular lens is by far the best solution to correcting vision after cataract surgery. The proper placement of an intraocular lens always involves the risk of damage to the eye during the insertion process as well as at a later time period if the intraocular lens dislocates or must be removed and/or replaced.

Lenses are known which permit posterior chamber fixation. At least one design of the Shearing lens employs a pair of resilient legs attached to the lens. One resilient leg of the Shearing lens is placed through a chemically dilated pupil to the area of the ciliary sulcus. The second resilient leg is coiled and forced through the pupil with the lens to the posterior chamber. The second resilient leg is released and springs back behind the iris toward the ciliary sulcus at a position therein opposite to that of the first resilient leg. The Shearing lens is preferably used only with extra capsular surgery since additional support, by the remaining posterior wall of the capsule, is available if good fixation at the ciliary sulcus is not achieved. In addition, care must be exercised during insertion of the Shearing lens since otherwise there may result severence of the zonules which would allow the Shearing lens to travel into the vitreous humor behind the iris. While maximum pupil size is desirable to facilitate proper fixation of these known posterior chamber lenses, adequate dilation of the pupil is not possible in every case. Moreover, the releasing of the second resilient leg of a Shearing lens creates a whip-like action which can tear the iris, or the ciliary body, or the posterior capsule, resulting in bleeding and loss of capsular support. Moreover, forcefully retracting the iris with a forceps to allow the second resilient leg to pass behind it can also cause damage to the iris. All in all, suitable posterior fixation of the Shearing lenses is difficult to predict and visualization of the fixation is totally impossible since the ciliary sulcus is totally hidden by the iris and is, therefore, invisible to the surgeon. Furthermore, removal of such a lens, should such be indicated at some later date, is extremely difficult and sometimes dangerous.

There is a need for a lens which may be easily fixed into the posterior chamber of the eye, which offers a superior means of support without substantial damage to the eye during and after implantation, and which will facilitate removal of the lens at a later date should such removal be indicated.

In accordance with the invention, an intraocular lens suitable for use as an artificial lens implant comprises a medial, light-focusing, lens body intended to be positioned adjacent the pupil on one side of the iris and at least a pair of position fixation elements connected with the lens body. One of the position fixation elements has a first portion contiguous to and extending generally laterally outwardly from a first region of the periphery of said lens body and intended to extend to and seat adjacent the periphery of the iris on the aforesaid one side thereof. The other of the position fixation elements has a first portion extending from the lens body and intended to extend through the pupil of the eye from the aforesaid one side of the iris to the other side of the iris and another portion extending from the first portion generally laterally outwardly from a second region of the periphery of the lens body spaced from the aforesaid first region and in a direction generally opposite to that of the aforesaid first portion of the aforesaid one position fixation element and intended to extend to and seat adjacent the periphery of the iris on the aforesaid other side thereof.

Also in accordance with the invention, an intraocular lens suitable for use as an artificial lens implant having an optical zone positioned posteriorly of the iris comprises a medial, light-focusing lens body and at least a pair of position fixation elements connected with the lens body. At least one of the pair of position fixation elements has a first portion contiguous to and extending generally laterally outwardly from a first region of the periphery of the lens body for seating in the sulcus of the posterior chamber or the sulcus of the capsule. The other of the pair of position fixation elements has a first portion extending generally axially from the lens body and another portion extending from the first portion generally laterally outwardly from a second region of the periphery of the lens body spaced from the first region and in a direction generally opposite to that of the first portion of the aforesaid one position fixation element for extending to the periphery of the iris for seating in the anterior chamber angle of the eye.

Also in accordance with the invention, the method of inserting the optical zone of an intraocular lens into the posterior chamber of an eye comprises inserting a first position fixation element, extending generally laterally outwardly from the lens body, through the pupil into the ciliary sulcus of the posterior chamber or into the sulcus of the capsule. The method also includes inserting a second position fixation element, extending outwardly from the lens body, into the anterior chamber angle of the eye.

Means for urging engagement of the first and second position fixation elements to the periphery of the iris may take the form of a spring mechanism and the like. It has been found that simply forming at least a portion of the first and second position fixation elements of resilient material produces a spring-like effect. In addition, each position fixation element may be an elongated member having a curved end portion with a blunted tip or cap to prevent damage to the eye tissue during and after insertion of the lens structure.

It is an object of the present invention to provide an intraocular lens structure which may be employed to correct aphakia after cataract surgery accomplished by extra capsular cataract extraction.

It is yet another object of the present invention to provide an intraocular lens structure which may be inserted without the necessity of chemical dilation of the pupil.

It is a further object of the present invention to provide an intraocular lens structure which may be more easily inserted by the less experienced surgeon into the posterior chamber of the eye without tearing the iris tissue.

It is a still further object of the present invention to provide an intraocular lens structure, and method for inserting the same, for which the user is able to visually guide at least one means of fixation of the optical zone and to stabilize the lens structure during insertion thereof in the posterior chamber of the eye.

It is a concomitant object of the invention to provide an intraocular lens structure for implantation in the posterior chamber of the eye and which may be readily removed therefrom.

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

FIG. 1 is a plan view of an embodiment of the present invention intended for fixation partly in the posterior and partly in the anterior chamber of the eye.

FIG. 2 is a side elevational view of the intraocular lens structure of FIG. 1 fixed within an eye, shown in section.

FIG. 3 is a plan view of another embodiment of the present invention intended for fixation partly in the posterior and partly in the anterior chamber of an eye.

With reference to the drawings the invention as a whole is depicted on the figures illustrated thereupon and denoted by reference character 10. The intraocular lens structure 10 includes as one of its elements a medial, light-focusing lens body or optical zone 12, FIG. 1. The lens body 12 may be constructed of any biologically inert and transparent material suitable for optical correction such as methylmethacrylate, quartz, ophthalmic glass, and other materials known in the art.

At least a pair of position fixation elements 13, 17 are connected with the lens body 12. First position fixation element 13 has a first portion 14 contiguous to and extending generally laterally outwardly from a first region of the periphery of the lens body 12. First and second position fixation elements 13, 17 may be molded integrally with lens body 12 or connected by an adhesive, ultrasonic welding, fusion, or any other connection method known in the art. As may be seen from FIG. 1, first position fixation element 13 is an elongated member having a relatively straight portion 14 and a curved end portion 15. In other words, straight portion 14 connects to lens body 12 at the proximal end and to curved portion 15 at the distal end thereof. A knob 16 is fixed to the terminal portion 15 to prevent damage to human tissue within the eye. It should be noted that first position fixation element 13 is constructed of biologically inert and nonabsorbative material such as methylmethacrylate, polypropylene, platinum, and the like. The present embodiment anticipates that first element 13 is resilient or springy such that it will return to the position shown in FIG. 1 after compression or extension away from the illustrated configuration.

As seen in FIG. 2 lens structure 10 embraces a second position fixation element 17 as a necessary element thereof. Second element 17 includes a first portion 18 extending generally axially from the lens body, that is, generally parallel to the optical axis of the lens body. Second element 17 has another portion 19, 20, 22 extending from the first portion 18 generally transversely thereto and in a direction generally laterally outwardly from a second region of the periphery of the lens body 12 spaced from the first region and in a direction generally opposite to that of the first position fixation element 13 for extending to the periphery of the iris for seating in the anterior chamber angle of the eye in the vicinity of the scleral spur 50.

The first portion 18 of the second position fixation element 17 has a length of, for example, two millimeters. A second portion 19 of the second position fixation element 17 preferably extends at substantially a right angle from the first portion thereof. The second position fixation element 17 preferably has a third portion 20 extending obliquely from the second portion toward the plane of the lens body perpendicular to the optical axis 21 of the lens body.

The second position fixation element 17 has a fourth portion extending from the third portion parallel to the aforesaid plane and having a curved end portion 22 for seating in the anterior chamber angle 33' of the eye in the vicinity of scleral spur 50. The distance between the curved end portion 22 and a plane perpendicular to the optical axis and extending to the surface of the lens body closest to the curved end portion 22 is, for example, approximately one millimeter. The seating portion 22 is located in a plane perpendicular to the optical axis of the lens body intermediate the distal and proximal ends of the first portion 18 of the second position fixation element 17.

The second position fixation element 17 may be made of the same material as the first position fixation element 13 and preferably is resilient or springy such that it will return to the position shown in FIG. 1 after compression or extension away from the illustrated configuration.

Lens structure 10 is intended for insertion and fixation within an eye 30, after cataract removal by extra capsular surgical procedure. Eye 30 includes a cornea 31 having an endothelial layer 32. Anterior chamber 33 and posterior chamber 34 are defined by the position of iris 35. FIG. 2 shows eye 30 after an extra capsular surgical procedure in which, after the natural lens has been removed, a relatively flattened posterior capsule membrane 36, as well as a small part of anterior capsule 36a remains. The natural lens is normally connected to the ciliary body 36' by a plurality of zonules 37. Ciliary sulcus 38 of the posterior chamber is located between the sulcus of the capsule 36 and the iris 35. As used in this specification and in the claims, the term "adjacent the periphery of the iris", referring to seating, includes seating in the anterior chamber angle of the eye in the vicinity of the scleral spur 50, seating in the sulcus of the capsule 36, 36a, and seating in the ciliary sulcus 38.

As shown in FIG. 2, lens structure 10 may be placed in posterior chamber 34 through pupil 41, which may be chemically dilated. Initially, lens structure 10 is slipped through an opening 42 of cornea 31 above the end of endothelial layer 32 which aligns with pupil 41. A pair of tweezers is employed to stabilize and to steer optical zone 12 and first element 13 through pupil 41 and into seating engagement with the sulcus of capsule 36 and 36a or with ciliary sulcus 38. Second element 17 is then seated in the anterior chamber angle 33', and thus resists any tendency of the lens structure 10 decentering superiorly. Similarly, the seating of first element 13 in the capsule sulcus or ciliary sulcus, as the case may be, prevents the lens from decentering inferiorly. The iris behind element 17, as well as the posterior capsule 36 prevent the lens from falling backward into the vitreous cavity 40. Curved portion 15 of first element 13 fits within the ciliary sulcus at the periphery of the iris serving as a means for primary support of optical zone 12.

Second element 17 extends through the pupil 41 such that end portion 22 seats in the anterior chamber angle 33' to offer a positive means of secondary support for lens body 12 of lens structure 10.

FIG. 3 depicts another embodiment of the present invention wherein a resilient first position fixation element 13a has a first portion extending generally laterally from the lens body and a second portion extending from the end of the first portion generally transversely thereto and at least partly peripherally of the lens body to provide two points of support for the lens in the ciliary sulcus of the posterior chamber, or in the sulcus of the capsule 36. The remainder of the FIG. 2 lens structure is similar to the FIG. 1 structure.

From the foregoing description it will be apparent that a lens constructed in accordance with the invention has the advantage that its lens body may be readily inserted into the posterior chamber and yet have one of its position fixation elements seated in the anterior chamber angle where it can be seen both for implantation and for subsequent surgical removal, if necessary, thus facilitating both the implantation and any subsequent removal. Further, surgeons have nearly twenty years of experience with seating position fixation elements in the anterior chamber angle while they have only three or four years experience with positioning position fixation elements in the posterior chamber, thereby not only facilitating the surgical procedure but even more importantly providing a degree of confidence regarding the safety and efficiency of the procedure and of the resulting implant.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein whithout departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.