WO1991015166A1

WO1991015166A1 - Implantable intraocular lens

Info

Publication number: WO1991015166A1
Application number: PCT/NL1991/000055
Authority: WO
Inventors: Peter Jansen
Original assignee: Kabi Pharmacia Ab
Priority date: 1990-04-03
Filing date: 1991-04-02
Publication date: 1991-10-17
Also published as: NL9000779A; AU7684491A

Abstract

The invention relates to an implantable intraocular lens comprising an optical portion (2) and a plurality of fixation members connected to the optical portion (2) along the circumference thereof. The fixation members comprise a flexible anchoring ring extending around the optical portion (2) and a plurality of curved flexible fixation arms which connect the anchoring ring to the optical portion (2). According to the invention, the anchoring ring has a polygonal shape.

Description

Title: Implantable intraocular lens.

This invention relates .to an implantable intraocular lens comprising an optical portion and a plurality of fixation members connected to said optical portion along the circumference thereof. In a cataractic eye, the lens is opacified and is removed. The absence of the lens is then compensated for by introducing an artificial lens, the so-called intraocular lens . The intraocular lens is implanted by means of surgery, often together with the removal of the opacified natural lens . The intraocular lenses can be implanted in the anterior chamber, in the pupil, or in the posterior chamber. In the last case, which is preferred in the great majority of cases at present, the intraocular lens can be placed either within the so-called capsular bag or between the capsular bag and the iris. The capsular bag is a membrane surrounding the lens proper and is often left in the eye, at least in the case of extracapsular extraction, when the opacified lens is removed.

An artificial intraocular lens consists of a central optical portion and fixation members. These members may be made separately and then interconnected, or may be made of the same piece of material.

In the first case, the lens is sometimes referred to as a three-piece lens, at least if two fixation members are used. In the second case the lens would be called a one-piece lens . The fixation members provide for the suspension of the lens at a suitable position within the eye. The shape of these members, often referred to as loops, is partly determined by the position within the eye where the lens is implanted.

It is well known to form a lens, often of the one-piece type, with a flexible circular anchoring ring extending around the optical portion, which ring is connected to the optical portion by means of a plurality of curved, flexible fixation arms.

Such a lens is known, for example, from European patent application 0 289 449. An advantage of the use of a circular anchoring ring is that it can be formed such that the ring fits exactly into the lens capsule, so that the ring abuts the tissue of the capsule over a comparatively large area. The bearing forces per unit area will then be minimal, so that the chance of the tissue becoming irritated is small.

A practical problem, however, is that the dimensions of the lens capsule may vary from one person to another. Accordingly, there is a need for a lens with fixation members such that, on the one hand, the advantages of a circular anchoring ring are retained as much as possible and, on the other, the anchoring ring is capable of adjusting to a certain extent to the dimensions of a lens capsule.

It is an object of the invention to provide for the need outlined and generally to provide an effective intraocular lens adapted for simple and efficient implantation. To that effect, according to the invention, an implantable intraocular lens of the type described hereinabove is characterized in that the anchoring ring has a polygonal shape.

Hereinafter, the invention will be further described, by way of example, with reference to the accompanying drawings of some embodiments.

Fig. 1 schematically shows a first embodiment of a lens according to the invention;

Fig. 2 schematically shows a second embodiment of a lens according to the invention; Fig. 3 schematically shows a third embodiment of a lens according to the invention;

Figs . 4 and 5 schematically show two variants of the embodiment according to Fig. 1;

Fig. 6 schematically shows a fourth embodiment of a lens according to the invention; and

Fig. 7 schematically shows a fifth embodiment of a lens according to the invention.

Fig. 1 shows a first embodiment of an implantable intraocular lens 1 according to the invention with a central optical portion 2, which forms the lens proper, and an annular anchoring member 3. The annular anchoring member is connected to the optical portion by means of a plurality - three, in this embodiment - of flexible, approximately S-shaped arms 4, 5, 6. The arms 4, 5, 6 are disposed in substantially the same plane as the anchoring ring 3.

The anchoring ring is not circular, as is the case in the prior art, but is formed as a regular polygon. In the embodiment of Fig. 1, the anchoring ring is substantially shaped as an equilateral triangle with slightly outwardly curved sides 7 between the corners 8. Further, the corners have a rounded form. The polygonal form makes it possible to reduce to a certain extent the maximum external dimensions of the ring, without the ring elsewhere bulging out beyond the circumference of the circumscribed circle of the polygonal ring. When a circular anchoring ring is used, such bulging does occur, so that a lens with a circular anchoring ring must always be accurately adapted to a given patient .

The three corners 8 can be moved radially towards the optical portion without the sides 7 bulging out beyond the circumscribed circle C of the polygonal ring. This means that the lens is not only suitable for use in capsules whose internal diameter is equal to the diameter of the circumscribed circle of the polygonal anchoring ring, but also for capsules whose internal diameter is smaller. Since the corners 8 are rounded and acquire a yet further rounded shape when the anchoring ring is slightly compressed, the pretension under which the anchoring ring is disposed in the capsule will remain small per unit area in all practical situations.

The S-shaped arms do not impede the compression of the anchoring ring and are preferably connected to the anchoring ring halfway between the corners. In the embodiment of Fig. 1, three S-shaped arms are used. By way of example, Figs. 4 and 5 show a lens with a substantially triangular anchoring ring 3 and four S-shaped arms 11, 12, 13, 14 and 16, 17, 18, 19, respectively. In the embodiment of Fig. 4 the arms 13 and 14 have a common point of attachment 15 on the anchoring ring. The points of attachment of the arms 11 and 12 on the lens are located comparatively close to each other, but comparatively far from the points of attachment of the arms 13, 14 on the lens. In the embodiment of Fig. 5, the arms 18 and 19 have a common point of attachment 20 on one side of a triangular anchoring ring 3. The points of attachment of the arms 17 and 18 on the lens are located close to each other, as are the points of attachment of the arms 16 and 19 on the lens. In all cases shown, the arms are connected to the anchoring ring approximately halfway between the corners . By way of example, Fig. 2 shows a lens comprising a substantially square anchoring ring 30 with slightly outwardly curved sides 30 through 34 and rounded corners 35 through 38. In this embodiment, two S-shaped fixation arms 39, 40 are used, arranged oppositely and symmetrically, again connected to the central portions of two sides of the anchoring ring. In principle, it is also possible to use more fixation arms, for example one fixation arm for each side of the anchoring ring, or fixation arms with a common point of attachment on the ring, in a manner similar to that shown in Figs. 4 and 5. Fig. 3 schematically shows an embodiment of a lens according to the invention with an anchoring ring formed as a regular hexagon, which is connected to an optical portion 2 by means of two S-shaped fixation arms . In this case, too, variants with more and/or jointly attached fixation arms are possible.

It is observed that the number of corners may be different from that shown in the figures. Generally, in the case of a greater number of corners, the anchoring ring is disposed in the capsule under a smaller pretension, but, on the other hand, the area over which the anchoring ring can be compressed without bulging out beyond the circumscribed circle, is smaller. In this connection it is observed that it is expected that the embodiment shown in Fig. 3 will be particularly suitable.

It is noted that, after reading the foregoing, various modifications will readily occur to those skilled in the art. Thus, it is not strictly necessary for the anchoring ring to have a regular shape, i.e. the shape of an equilateral polygon. Further, as a borderline case, an elliptical shape could also be seen as a polygonal (biangular) shape within the meaning of the invention. Fig. 6 schematically shows one embodiment of a lens with an elliptical anchoring ring 60.

Fig. 7 schematically shows an embodiment of a lens with a pentagonal anchoring ring 70, which is connected to the lens by means of three fixation arms 71, 72, 73. Fig. 7 further shows, by means of broken lines, the circumscribed circle Cl of the pentagonal anchoring ring. Furthermore, C2 indicates the circumscribed circle such as it may apply to the anchoring ring 70 when it is arranged in a capsular bag in a slightly compressed position. These and similar modifications are to be understood to fall within the scope of the invention.

Claims

A I M S

1. An implantable intraocular lens comprising an optical portion and a plurality of fixation members connected to the optical portion along the circumference thereof, the fixation members comprising a flexible anchoring ring extending around the optical portion and a plurality of curved flexible fixation arms which connect the anchoring ring to said optical portion, characterized in that the anchoring ring has a polygonal shape.

2. An implantable intraocular lens according to claim 1, characterized in that the polygonal shape is an equilateral polygo .

3. An implantable intraocular lens according to claim 1 or 2, characterized in that the polygonal shape has rounded corners.

4. An implantable intraocular lens according to claim 1, 2 or 3, characterized in that the polygonal shape has sides curved slightly outwardly.

5. An implantable intraocular lens according to any one of the preceding claims, characterized in that the fixation arms are connected to the anchoring ring in the central area of at least two sides of the polygonal anchoring ring.

6. An implantable intraocular lens according to any one of the preceding claims, characterized in that the points of attachment of the fixation arms and the anchoring ring are uniformly spaced along the circumference of the anchoring ring.

7. An implantable intraocular lens according to any one of the preceding claims, characterized in that at least one pair of fixation arms are connected to the anchoring ring at a common point of attachmen .

8. An implantable intraocular lens according to any one of the preceding claims, characterized in that the anchoring ring is elliptically shaped.