WO1991009575A1

WO1991009575A1 - Intraocular lens with scleral fixation and method

Info

Publication number: WO1991009575A1
Application number: PCT/US1990/007493
Authority: WO
Inventors: Milton Chu
Original assignee: Milton Chu
Priority date: 1989-12-26
Filing date: 1990-12-18
Publication date: 1991-07-11

Abstract

An intraocular lens (30) is provided with haptics (34, 36) that have at least one suture hole (40) for scleral fixation of the lens (30) to the eye (10). The suture hole (40) prevents relative movement between the suture (44) and the haptic (34, 36). Another embodiment provides tabs (86, 96) attached to the lens haptics (84, 94), the tabs having at least one suture hole (88, 98) extending through the tabs (86, 96). The suture holes (40) can be directed radially in the transverse plane of the lens optic (32). In that case, each suture hole (40) guides the needle (45) and suture (44) in the proper direction and orientation for proper scleral fixation of the lens (30). The suture holes (88) can also be directed axially, that is, substantially perpendicular to the transverse plane of the lens optic (82). In an alternative embodiment, the lens haptics (54, 56) are provided in a closed loop design with a smaller overall length to fit more easily in the ciliary sulcus (42).

Description

INRAOCULAR LENS WITH SCLERAL FIXATION AND METHOD

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to intraocular lenses and, more particularly, to intraocular lenses having haptics adapted for scleral fixation.

2. Description of the Related Art

FIG. 1 is a cross-sectional view of a typical, healthy human eye 100. The human eye is a generally spherical body defined by an outer wall called the sclera 110, having a transparent bulbous front portion called the cornea 112. The lens 114 of the human eye is located within the spherical body, behind the cornea. The iris 116 is located between the lens and the cornea, dividing the eye into an anterior chamber 120 in front of the iris and a posterior chamber 118 in back of the iris. A central opening in the iris, called the pupil 122, controls the amount of light that reaches the lens. Light is focused by the cornea and by the lens onto the retina 124 at the rear of the eye. The lens is a bi-convex, highly transparent structure surrounded by a thin lens capsule 126. The lens capsule is supported at its periphery by suspensory ligaments called zonules 128, which are continuous with the ciliary muscle 130. The focal length of the lens is changed by the ciliary muscle. Just in front of the zonules, between the ciliary muscle and iris, is a region referred to as the ciliary sulcus 132. A cataract condition results when the material within the lens 114 becomes clouded, thereby obstructing the passage of light. To correct this condition, three forms of surgery are used, known as intracapsular extraction, extracapsular extraction, and phacoemulsification. In intracapsular cataract extraction, the zonules 128 around the entire periphery of the lens capsule are severed; the entire lens structure, including the lens capsule 126 is then removed. In extracapsular cataract extraction and phacoemulsification, only the clouded material within the lens is removed, while the transparent posterior lens capsule wall with its peripheral portion, as well as the zonules, are left in place in the eye.

Intracapsular extraction, extracapsular extraction, and phacoemulsification eliminate the light blockage due to the cataract condition. The light entering the eye, however, is thereafter unfocused due to the lack of a lens. A contact lens can be placed on the exterior surface of the eye, but this approach has the disadvantage that the patient has virtually no useful sight when the contact lens is removed. A preferred alternative is to implant an artificial lens, known as an intraocular lens, directly within the eye. An intraocular lens generally comprises a disk-shaped, transparent lens optic and two smooth curved attachment arms referred to as haptics. The lens is implanted through an incision made near the periphery of the cornea, which may be the same incision used to remove the cataract. An intraocular lens may be implanted in either the anterior chamber of the eye, in front of the iris, or in the posterior chamber, behind the. iris. An anterior chamber lens is supported by contact of the haptics with a corner, or angle, of the anterior chamber 120 which is formed by the union of the iris 116 and the cornea _.112. In the case of a posterior chamber lens, there are two methods of support. In the first method, the intraocular lens and its haptics are placed in the sack-like structure formed by the intact posterior and peripheral walls of the lens capsule. The haptics are compressed slightly against the periphery of the lens capsule and thereby hold the intraocular lens in place. In the second method, the intraocular lens is placed in front and outside of the lens capsule. The haptics are sandwiched between the iris 116 and zonules 128 in the region of the ciliary sulcus 132 and thereby hold the lens in place. Anterior chamber lenses differ significantly in design from posterior chamber lenses. Accordingly, one cannot be used in substitution for the other.

Experience has shown that intraocular lenses implanted in the anterior chamber dramatically increase the risk of significant complications. Anterior chamber lenses have been known to cause hyphema, uveitis, iris chaffing, glaucoma, cystoid macular edema, persistent ocular pain and redness, and pseudophakic bullous keratopathy. As a result of treating these conditions and other complications, anterior chamber lenses need to be explanted, or removed, approximately twenty times more often than posterior chamber lenses. For these reasons, when adequate zonular or capsular support is present, the posterior chamber lens remains the surgeon's first choice. Unfortunately, adequate zonular or capsular support is not always present. Certain abnormalities of the eye, traumatic injury to the eye, previous intracapsular surgery, or an intra-operative complication during extracapsular or phacoemulsification surgery, all may result in loss of the capsular or zonular support for a posterior chamber lens. Until now, the surgeon has had no choice but to implant an anterior chamber lens.

However, surgeons have recently succeeded in 5 implanting intraocular lenses in the posterior chamber in the absence of capsular and zonular support by suturing the lens to the sclera of the eye. The lens haptics are usually sutured to the sclera at or near the ciliary sulcus. The small number of surgeons who have

10 experimented with scleral fixation have reported promising results. Early reports show that intraocular lenses attached to the eye by scleral fixation are well tolerated, provide good vision, and bear significantly fewer complications than anterior chamber lenses. If

15. these promising results continue to be confirmed and if present trends continue, scleral-fixated posterior chamber lenses could make anterior chamber lenses obsolete.

Standing in the way of rapid adoption of scleral fixation for posterior chamber lenses is the fact that

20 specialized lenses and materials to perform the procedure are not yet available. Most ophthalmic surgeons can easily acquire the surgical skills needed for scleral fixation. Suitable sutures and needles are presently available for the procedure, such as the 10-prolene suture

25 and the Ethiσon CIF-4 or STC-6 needles. There is, however, no presently available intraocular lens designed specifically for scleral fixation.

At present, ophthalmic surgeons use conventional posterior chamber lenses and simply tie the fixation

30 sutures to the lens haptics. There are several drawbacks to this technique. First, because the fixation suture is tied to the smooth haptic, migration of the haptic and lens optic relative to the suture is possible. Such migration could lead to lens decentration, lens tilt, or even complete loss of lens fixation. Second, the process of tying the suture to the lens haptic (generally with a double knot or a clove hitch) is a difficult, time consuming, and often frustrating procedure. If the suture is tied to the haptic with a double knot, the end of the suture may irritate the inside of the eye. These problems are amplified by the need to repeat the procedure for each haptic. Third, current posterior chamber lenses are considered too large for scleral-fixated placement in the typical posterior chamber. The diameter of the typical ciliary sulcus measures about 11 millimeters, while the typical posterior chamber lens measures 14 millimeters across. Finally, the haptics of current posterior chamber lenses do not provide optimal stability of the lens optic in the absence of the lens capsule. Such instability can lead to lens tilting and can introduce uncorrectable optical problems after scleral fixation.

It should therefore be appreciated that there is a need for a new type of intraocular lens, and a new procedure for implanting it, for implantation in the eye by scleral fixation. The present invention fulfills this need.

SUMMARY OF THE INVENTION

In accordance with the present invention, an intraocular lens is provided with at least one suture hole located near the mid-point of each lens haptic for suturing the lens to the sclera. As with conventional intraocular lenses, the haptics are attached to, and project outwardly from, opposite points on the lens optic's circumference, substantially in the transverse plane of the lens. In one embodiment, the haptics each have at least one suture hole extending in the transverse plane of the lens optic and directed radially toward the sclera. When the .lens is implanted in the eye, a suture is fastened to the haptic through the suture hole, while the free end of the suture is attached to a needle. The radial direction of the haptic suture hole directs the needle and suture in the proper orientation for being passed through the sclera so the suture can be fastened to the eye with a knot, holding the intraocular lens in the correct position. In another embodiment, each haptic is provided with a tab at approximately its midpoint, the tab having at least one suture hole for use in suturing the lens to the sclera.

The lens of the present invention ensures that the haptic will not migrate from the point of scleral fixation. The suture holes prevent relative movement between the suture and the haptic. The lens also facilitates the procedure of securing the fixation suture to the haptic and thereby makes the scleral fixation procedure easier and faster, because the process of attaching the suture to the haptic is easier. Preferably, each suture hole is oriented in a direction toward the ciliary sulcus. The suture is thereby guided in the most direct route possible to the point of scleral fixation .by the suture hole. This eliminates the problem of torsional forces on the haptic that can be generated by interaction between the suture and the haptic. Such torsional forces can bow the lens out and can lead to lens descentration or tilting. In addition, the lens eliminates the necessity of maintaining an inventory of anterior chamber lenses, because the present invention provides an intraocular lens that can be implanted in the posterior chamber of the eye even in the absence of capsular support. Furthermore, a lens in accordance with the present invention can also be used in the posterior chamber without scleral fixation but with conventional capsular or zonular support.

In another embodiment of the present invention, the lens is provided with two suture holes in each haptic, rather than just one. This doubles the points of suture attachment to the haptic and lens fixation to the sclera. This is important because recent studies have shown that sclera-fixated lenses are supported entirely by their fixation sutures in both early and late post-operative periods. Furthermore, each free end of the suture may be attached to a needle, eliminating the need for attaching the suture to the haptic by a knot. In this way, only smooth suture surfaces are presented to the eye tissue, reducing the chance of irritation in the eye.

In yet another embodiment of the present invention, the lens includes a haptic in a closed loop configuration, rather than the conventional "C" or "J" open-loop configuration. The closed loop design provides better stability against optic tilt and decentration, and the absence of haptic ends minimizes the potential for irritation or intraocular trauma.

Finally, the lens can be provided in a smaller transverse size, approximately 12.5 millimeters, which is more suited for the dimensions of the ciliary sulcus as compared with the 14-millimeter size of typical posterior chamber lenses.

Other features and advantages of the present invention should become apparent from the following description of the preferred embodiments, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a typical healthy human eye.

FIG. 2 is a cross-sectional, perspective view of an intraocular lens in accordance with the present invention, implanted in an eye.

FIG. 3 is a perspective view of the intraocular lens illustrated in FIG. 2.

FIG. 4 is a perspective view of a portion of a second intraocular lens embodiment of the present invention, with dotted lines indicating axially-aligned suture holes in tabs secured to one of its haptics.

FIG. 5 is a perspective view of a portion of a third intraocular lens embodiment of the present invention, with dotted lines indicating radially-aligned suture holes in tabs secured to one of its haptics.

FIG. 6 is a plan view of a fourth intraocular lens embodiment of the present invention, with dotted lines indicating suture holes in its haptics.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following descriptions of the present invention are not to be taken in a limiting sense but are made merely for the purpose of illustrating the general principles of the invention. The scope of the invention is best defined by the appended claims. The following detailed descriptions are of the best - presently contemplated modes of carrying out the present invention.

FIG. 2 shows a first preferred embodiment of an intraocular lens 30 in accordance with the present invention, as implanted within the posterior chamber of an eye 10. The spherical body of the eye is defined by the sclera 12, with the eye's forward end being a transparent bulbous segment referred to as the cornea 14. An iris 16 extends radially inwardly at the juncture of the sclera and the cornea. The iris is a pigmented, ring- shaped mass of tissue that controls the amount of light passing to the lens. The central opening in the iris is referred to as the pupil 18. The iris divides the eye into a front or anterior chamber 20 and a rear or posterior chamber 22. A ciliary muscle 24 is located around the inside of the eye, behind the iris, with suspensory ligaments called zonules ordinarily extending from the ciliary muscle radially inward to a lens capsule that supports the lens of the eye. In FIG. 2, the lens, lens capsule, and zonules have been surgically removed.

The intraocular lens 30 in accordance with the present invention is shown in FIG. 2 implanted in the eye 10 within the posterior chamber 22, while the lens .is shown in perspective in FIG. 3. The lens 30 includes a disk-shaped lens optic 32 and curved first and second haptics 34 and 36, respectively, attached to the lens optic at opposite points on the lens optic's circumference. The haptics project outwardly substantially in the transverse plane of the lens optic.

In accordance with the invention, an apex portion 38 of each haptic includes a pair of radially- oriented suture holes 40 directed toward the ciliary sulcus 42, just anterior to the ciliary muscle 16. A suture 44 is threaded through a first of the suture holes in one direction and through the other suture hole in the opposite direction, and each free end of the suture is passed through the sclera 12 using a needle 45. The free ends are then secured together in a knot 46. When the suture is passed through the suture holes 40, the suture is held in a fixed position relative to the haptic, and thus there can be no migration of the haptic and lens optic. The suture holes, being radially directed toward the ciliary sulcus, guide the needle and suture in the most direct route possible to the point of scleral fixation. Because two suture holes are provided, there is no need to fasten the suture to the haptic with a knot, which eliminates one potential cause of irritation to the sclera. In the embodiment illustrated, only smooth surfaces are located at the point of fixation.

FIG. 4 is an enlarged perspective view of a second embodiment of the present invention. An intraocular lens 80 is shown having a disk-shaped lens optic 82 with an open loop haptic 84 (only one haptic of a pair is shown) . At its apex portion 85, the haptic includes a disk-shaped tab 86. Several methods of creating the tab can be used. The tab can be punch-cut from the material used to form the haptic, thereby becoming an integral part of the haptic when it is being formed, or alternatively the tab can be separately formed- and then attached to the haptic, for example, by localized heating that fuses the tab to the haptic, or by chemical bonding. The tab could also be integrally formed by pinching or flattening the apex portion 85 when the haptic has been formed and is still somewhat soft and pliable. The tab includes two suture holes 88 extending axially through it, i.e., in a direction substantially perpendicular to the transverse plane of the lens optic. The tab is provided with rounded edges, and is attached to the haptic such that it is unnecessary to provide suture holes through the haptic itself. Rather, the suture holes in the tab are clear of the haptic and, therefore, a suture and needle may be passed through the suture, holes for scleral fixation of the lens 80 to the eye. When a suture is passed through the suture holes, the suture is held in a fixed position relative to the haptic. Because there are two suture holes, the suture can be attached to the haptic without a knot. Once again, only smooth surfaces are presented at the point of fixation.

FIG. 5 is an enlarged perspective view of a third embodiment of the present invention. Like the embodiment of FIG. 4, the intraocular lens 90 has a disk- shaped lens optic 92 and a pair of open-loop haptics 94 (only one of which is illustrated) , with an apex portion 95 of each haptic having a tab 96. In the FIG. 5 embodiment, each tab includes a pair of suture holes 98 extending radially through the tab, i.e., in a direction substantially parallel to the transverse plane of the lens optic. The suture holes in the tab are clear of the haptic and, therefore, a suture and needle may be passed through the suture holes for scleral fixation of the lens 90 to the eye. Again, the tab can be formed as an integral part of the haptic or can be separately formed and attached to the haptic, for example, by heat fusing or chemical bonding. The suture holes 98 are directed transversely to guide the suture and needle in the most direct route to the ciliary sulcus and the point of scleral fixation. When a suture is^' passed through the suture holes, the suture is held in a fixed position relative to the haptic. Only smooth surfaces are presented at the. point of fixation.

FIG. 6 shows yet another preferred embodiment of an intraocular lens in accordance with the present invention. The lens 50 includes a disk-shaped lens optic 52 and two closed loop haptics 54 and 56 oriented generally in the plane of the lens optic. The haptic 54 is attached to the lens optic at points 58 and 60, and the other haptic 56 is attached to the lens optic at points 62 and 64. The apex 66 of each closed loop haptic includes two suture holes 68 extending radially outwardly through the haptic, in the transverse plane of the lens optic 52.

The lens of FIG. 3 may be attached in the posterior chamber of the eye in the same manner as that illustrated in FIG. 2. In particular, a needle and suture are passed through the suture holes 68 and are then guided by the holes to the sclera. The closed loop haptic design provides better stability against tilting of the lens optic and resists decentration better than conventional open loop haptic designs for posterior chamber lenses, and can be made with a smaller overall length to fit more easily in the ciliary sulcus. In addition, the closed loop haptic design eliminates the free ends of the haptics that could potentially be a source of eye irritation or intraocular trauma.

The present invention has been described above in terms of several presently preferred embodiments so that an understanding of the present invention may be conveyed. There are, however, many configurations for lenses not specifically described herein, but with which the present invention is applicable. The present invention should therefore not been seen as limited to the particular embodiments described herein, but rather, it should be understood that the present invention has wide applicability with respect to lenses and haptics. Such other configurations may be achieved by those skilled in the art in view of the descriptions herein.

Claims

I claim:

1. An intraocular lens adapted for scleral fixation in the posterior chamber of an eye, the lens comprising: a disk-shaped lens optic having a transverse plane; and first and second curved position fixation haptics projecting outwardly substantially in the transverse plane of the lens optic from opposite points on the lens optic's circumference; wherein each haptic includes attachment means for receiving a suture that attaches the haptic to the surface of the eye's sclera and preventing relative movement between the suture and haptic.

2. The intraocular lens as recited in claim 1, wherein the attachment means comprises at least one suture hole extending radially through the haptic, substantially in the transverse plane of the lens optic.

3. The intraocular lens as recited in claim 1, wherein the attachment means comprises two parallel suture holes extending radially through the haptic, substantially in the transverse plane of. the lens optic.

4. The intraocular lens as recited in claim 1, wherein the attachment means comprises a tab attached to each haptic, with at least one suture hole extending through the tab.

5. The intraocular lens as recited in claim 4, wherein the suture holes extend axially through the tab, substantially perpendicular to the transverse plane of the lens optic.

6. The intraocular lens as recited claim 4, wherein the suture holes extend radially through the tab, substantially in the transverse plane of the lens optic.

7. The intraocular lens as recited in claim 4, wherein each tab includes two parallel suture holes extending through it.

8. The intraocular lens as recited in claim 7, wherein the parallel suture holes extend axially through the tab, substantially perpendicular to the transverse plane of the lens optic.

9. The intraocular lens as recited in claim 7, wherein the parallel suture holes extend radially through the tab, substantially in the transverse plane of the lens optic.

10. An intraocular lens adapted for scleral fixation in the posterior chamber of an eye, the lens comprising: a disk-shaped lens optic having a transverse plane; and first and second curved position fixation haptics attached to, and projecting outwardly substantially in the transverse plane of the lens optic from, opposite sides of the lens optic's circumference; wherein the apex of each haptic includes at least one suture hole extending radially through the haptic, substantially in the transverse plane of the lens optic, directed toward the eye's sclera and adapted to receive a suture for placement of the apex substantially adjacent the surface of the sclera.

11. An intraocular lens adapted for scleral fixation in the posterior chamber of an eye, the lens comprising: a disk-shaped lens optic having a transverse plane; first and second curved position fixation haptics attached to, and projecting outwardly substantially in the transverse plane of the lens optic from, opposite points on the lens optic's circumference; and a tab attached to the apex of each haptic, substantially in the transverse plane of the lens optic, with at least one suture hole extending through the tab and adapted to receive a suture that holds the tab substantially adjacent the eye's sclera.

12. A method of implanting an intraocular lens within an eye, the lens having a disk-shaped lens optic and first and second position fixation haptics attached to, and projecting outwardly substantially in the transverse plane of the lens optic from, opposite points on the lens optic's circumference, said method comprising the steps of: providing a lens with each haptic including a curved arm having at least one suture hole -at approximately the haptic's apex; passing a suture through the suture hole of each lens haptic, thereby attaching the suture to the haptic in a fixed position; inserting the intraocular lens into the posterior chamber of the eye for scleral fixation; passing each suture through the sclera of the eye to attach the haptic directly to the sclera; and fixing each suture by knotting the end of the suture against the sclera.

13. The method of claim 12, wherein the step of providing a lens includes a step of providing suture holes that extend radially through the haptic, substantially in the transverse plane of the lens optic.

14. The method of claim 12, wherein the step of providing a lens includes a step of providing suture holes that extend axially through the haptic, substantially perpendicular to the transverse plane of the lens optic.

15. The method of claim 12, wherein the step of providing a lens includes a step of attaching a tab to each haptic, each tab having at least one suture hole.

16. The method of claim 15, wherein the tab suture holes, provided in the step of attaching a tab extend radially through each tab, substantially in the, transverse plane of the lens optic.

17. The method of claim 15, wherein the tab suture holes, provided in the step of attaching a tab, extend axially through each tab, substantially perpendicular to the transverse plane of the lens optic.