WO1992017132A1

WO1992017132A1 - Artificial eye-lens

Info

Publication number: WO1992017132A1
Application number: PCT/AT1992/000036
Authority: WO
Inventors: Albert Daxer
Original assignee: Albert Daxer
Priority date: 1991-03-25
Filing date: 1992-03-19
Publication date: 1992-10-15

Abstract

The invention concerns an artificial lens intended for implantation in the eye, the lens having an optically operative main body (7, 17) and, located substantially the circumference of this main body (7, 17), a holding device. Implantation is facilitated and good optical properties ensured by virtue of the fact that the holding device is a hollow, flexible body (6, 16a, 16c) designed to be filled with a fluid after implantation.

Description

ARTIFICIAL LENS

The invention relates to an artificial lens for implantation in an eye with an optically effective lens body and a clamping device arranged essentially along the circumference of this lens body.

In cataract (cataract) the natural lens of the eye is clouded, which means that there is often a massive impairment of vision. During the surgical operation, the cloudy, natural eye lens is removed. In order to correct the resulting reduction in the total refractive power of the respective eye, artificial intraocular lenses are implanted. It is essential that the surgical opening through which the lens is implanted is kept as small as possible in order to avoid as much as possible an astigmatism caused by the surgical wound.

The aim today is to implant the intraocular lens anatomically exactly at the location of the removed natural eye lens. The natural eye lens is surrounded by a lens capsule which remains during the cataract operation with the exception of a hole on the front surface. The intraocular lens is then implanted in this capsular bag.

A few remaining lenticular epithelium residues in the capsular bag can in many cases lead to proliferation and fibrosis processes and subsequently to the so-called post-star, i.e. a clouding and warping of the capsular bag.

The currently most frequently implanted intraocular lenses consist of the optically improving lens body made of polymethyl methacrylate (PMMA), to which thin, flexible plastic brackets are attached as a holding device. These intraocular lenses have the disadvantage that the opening of the eye for implanting the lens must be at least as large as the PMMA lens body of the intraocular lens. It follows from this that this cut must be closed by sutures, which leads to postoperative astigmatism as an undesirable side effect due to the pull on the cornea. Furthermore, decentrations between the optical axis of the eye and the intraocular lens can occur as a result of the capsular fibrosis mentioned above.

Surgical techniques are also known in which the natural lens body is first removed in a suction-rinsing process by means of a cannula. A highly flexible, folded artificial lens is then inserted through the same channel. This lens unfolds after it is released. However, since this lens is so flexible, it is unable to resist distortion forces caused by fibrosis, which leads to irregular astigmatism that is difficult to control. Furthermore, so-called injectable lenses are known, which consist of a dense filling sack that is implanted in the eye. The actual lens material is injected into the cavity of the filling sack after implantation. A disadvantage of such lenses is that only the volume of the lens is precisely defined by the construction. The curvature and thus the refractive power cannot be precisely predetermined.

From DE-A 31 19 002 synthetic lenses are known which consist of a lens body and a holding body. Openings are provided between these elements to allow the passage of aqueous humor. However, the problem of implantation remains. If the lens is made soft and flexible in order to allow an implantation through a small surgical opening, the stability is later too low, which means that an optically favorable position cannot be guaranteed. It is therefore also necessary to adjust the density of the lens precisely in order to keep hydrostatic forces as small as possible. In the case of a stiffer design, however, the problem of the large surgical wound arises.

DE-A 37 24 123 describes a hydrogel lens which is characterized in that the calculation index between an intraocular lens nucleus and its homogeneous environment shows a continuous transition with an essentially homogeneous and swellable lens construction. Due to the automatic swelling of the material, it changes its shape and volume during or after implantation, but there is no indication of a construction with a perilenticular filling bag.

EP-A 348 005 shows an intraocular lens filled homogeneously with optically refractive material, in which a distinction can be made between the lens body and the lens holder at most by the specific shape of the lens. There is no component that could correspond to a perilenticular filling sack.

WO-A 89/00032 is based on a lens body, along the circumference of which a holding device made of porous material is attached in accordance with a sandwich construction. It is not evident that a perilenticular filling sack is present. Rather, an ingrowth of fibrous eye tissue in the pores of the sponge-like holding body after the introduction of these substances into the lens body is mentioned. However, this appears to be incomplete and only serves to improve the connections between the lens body and the holder surrounding it. There is obviously a permeable connection for polymerizing substances between the lens body cavity formed by two hemispherical lens body walls pressed against one another and the porous holding sponge pressed in at its circumference. A somewhat stiff bracket cannot be achieved with this version.

The object of the invention is. to avoid these drawbacks and to create an artificial lens. which is both easily implantable and has good stability in the eye and thus has favorable optical properties. It is therefore provided according to the invention that the clamping device consists of a flexible hollow body which can be filled with a medium after the implantation.

It is essential to the invention that a sack construction is provided which serves as a holding device and clamping device. This clamping device can serve on the one hand to give a small lens body made of stiff material after the implantation a precisely defined position and on the other hand the Specify the exact shape of a flexible lens In the first case, the bag construction essentially serves as a holding body, which spreads the artificial lens in the eye, In the second case, the function of stabilizing the lens itself is used.

When filled, the hollow body preferably has an essentially toric shape and is arranged in the region of the circumference of the lens. As a result, both the holding function and the function of the shaping can be performed well.

It is advantageous if the optically active lens body consists of an at least temporarily flexible medium and is surrounded by a dense shell. The introduction of the lens is thereby facilitated.

In a preferred embodiment of the invention it is provided that the hollow body is arranged inside the shell. Alternatively or additionally, it can be provided that the hollow body is attached to the outside of the lens body. Depending on the application, there are advantages for the individual variants.

It is advantageous if the flexible medium can be filled into the envelope of the lens body after the implantation of the lens in the eye. As a result, a particularly small operation opening can be realized.

The interior of the envelope of the lens body is preferably closed off from the interior of the hollow body. This allows the geometrical shape of the implanted lens to be precisely defined.

Furthermore, the invention relates to a device for changing the refractive power of an artificial lens described above. This consists of a suction pump device, a device for measuring the refractive power of the artificial lens and a control device which controls the suction pump device as a function of the measured refractive power. As a result, the refractive power of the lens can be set exactly to the required value during the operation, whereby all uncertainty factors or sources of error of a preoperative calculation can be switched off.

A particularly simple implementation of the lens adjustment is possible if a further suction pump device is provided for connection to the envelope of the lens body.

The invention is explained in more detail below on the basis of the exemplary embodiments shown in the figures. The figures show: FIG. 1 a human eye in section, FIG. 2a a plan view of an artificial lens according to the invention, FIG. 2b a section along the line - in FIG. 2a, FIG. 3a a section through an embodiment variant 3b shows a section through a modification of the variant of FIG. 3a, FIG. 4 shows a further embodiment variant, FIG. 5 schematically shows a filling device and FIG. 6 shows a device for automatic emmetropization.

The natural eye lens of Fig. 1 is surrounded by a lens capsule 3, which remains during the cataract operation except for a hole 4 on the front surface. The intraocular lens 5 is then implanted into the capsular bag 3 through this hole 4. In principle, an implantation is also in the anterior chamber I and in the posterior chamber, e.g. possible in the Sulcus Ciliaris 2 outside the capsular bag.

The embodiment shown in FIGS. 2a and 2b with a filling bag construction 6 on a fixed, non-deformable lens body 7 (for example made of PMMA) is excellently suitable for implantation into an eye according to the ECCE, Method (Extra Capsular Cataract Extraction) as used for PMMA intraocular lenses with two flexible holding brackets. This requires a star cut, which must be at least the size of the solid lens body. The star cut is finally closed with sutures. Along the circumference 7a on the edge of the lens body 7, a toric, empty filling sack 6, which is arranged concentrically around the optical axis 9, is fastened. The filling bag 6 should be made of flexible, dense and biocompatible material (e.g. PVC, polyethylene, etc.). The connection and the filling bag 6 itself are sealed against the leakage of filling material from the environment. A fill hole 8 can be connected to a fill pipe. After implantation into the eye, filler material which polymerizes after insertion, preferably after additional irradiation from a cold light source, can be introduced via these structures. The attachment can be realized, for example, using adhesive or welded bonds. The filling bag 6 is empty before the implantation and folded in such a way that it causes practically no enlargement of the overall dimension compared to the bare lens body 7. The filling tube can be used as an implantation instrument. After introducing this intraocular lens into the capsular bag or into the rear eye chamber, the filling bag 6 is filled with a suitable filling material and clamps the lens centered. The filled filling bag 6 acts as a holding device. An additional advantage of such a lens is that, in contrast to constructions with flexible holding brackets, it can also be implanted in the rear chamber when the rear lens capsule is torn. Furthermore, in contrast to the intraocular lenses with a holding bracket, there is a holding pressure that remains constant around the entire circumference. After the filling material has polymerized, it hardens, which leads to a firm fit and considerable resistance to decentration of the implanted optics as a result of postoperative capsular fibrosis.

The embodiment shown in FIG. 3a has a perilenticular filling bag 16a around a flexible lens body 7. The foldable, flexible lens body 7 is introduced into a thin-walled, transparent, flexible and biocompatible bag 16b (for example made of PVC, polycarbonate). polyethylene, etc.). A toric filling bag 16a is coaxially attached to this bag 16b. This filling bag 16a is attached to the bag 16b in a circular manner, preferably with a welded or adhesive connection along the entire circumference 18. This connection 18 as well as the filling bag 16a itself are sealed against leakage of filling material. The filling bag 16a has a small, round filling hole 8, to which a filling tube can be attached. The filling bag 16a is empty before the implantation. It is folded together with the flexible lens body 7 as small as is possible without plastic deformation of the lens body 7. After insertion into the posterior chamber of the eye, the flexible lens 7 unfolds due to the elastic forces occurring at the target location. The filling bag 16a is then filled via the filling hole 8, so that it fixes the intraocular lens in the capsular bag. After polymerization of the filling material, it is so hard that the main disadvantage of the flexible lenses used hitherto, distortion due to capsular fibrosis and the resulting postoperative astigmatism, can be prevented. The advantage of the flexible lenses, however, the compactness during implantation remains the same. A certain accommodation ability can be achieved by filling material that remains liquid.

In the modified embodiment variant according to FIG. 3b, a lens body is completely dispensed with before the implantation. The central sack 16b and the circular sack 16a are each empty before implantation in the eye. The lens body 17 is injected into the central sack 16b after implantation of this intraocular lens construction. Otherwise, this variant corresponds to that of FIG. 3a. Such an intraocular lens can of course be folded to minimal dimensions before implantations, which are even smaller than those of the flexible lens constructions. After implantations in the rear chamber, the circular sack 16a and the central sack 16b are filled with filling material. The filling material then polymerizes and hardens as a result. It must of course be transparent in the cured state. The advantage of this construction compared to previous injectable lenses is that a defined diameter of the lens body can be achieved by the circularly arranged filling bag 16a. This and the volume of the central sack 16b precisely define the radius of curvature of the lens body front surface 17a and the lens body rear surface 17b. The refractive power of the lens is precisely defined from the radii of curvature and the refractive index of the hardened filler material. This is not the case with the previously customary injectable single-chamber lenses, as a result of which relatively poorly reproducible optical results are achieved. Myopia up to 30 diopters postoperatively have been reported in the specialist literature. If the circular filling bag 16a is not made uniformly toric, but if the cross-section of the tonic is varied along the circumference, astigmatic ametropia can also be corrected. If only liquid filling material is used, the intraocular lens has an accommodative property, provided that it has been implanted in the capsular bag.

A further embodiment variant, in which the lens body circumference and the radius of curvature of the lens surfaces can be carried out independently of one another, is shown in FIG. 4. It consists of a central filling bag 16b and two further filling bags 16a and 10c arranged concentrically around the optical axis 9. an inner circular filling bag 16c and an outer circular filling bag 16a. The circular part thus corresponds to two separate chambers 26a and 26c, which are arranged coaxially concentrically and are each of a toric shape. The filling bags 16a and 16c forming these chambers 26a and 26c are connected to one another along the common circumferential line 18 by a welded or adhesive connection. In addition, as in the previously described embodiment variant, there is a central filling bag 16b with a chamber 26b. There are no direct connections between the chambers 26a, 26b and 26c. Before the implantation, they are empty and folded as small as possible. After the implantation, the filling bags 16a, 16b and 16c are filled individually with filling material. The inner circular filling bag 16c is to be arranged in relation to the central filling bag 16b in such a way that the inner circular filling bag 16c at least partially protrudes into the potential interior 26b of the central filling bag 16b. This enables all relevant parameters of an intraocular lens (external dimension of the entire intraocular lens, diameter of the lens body, radii of curvature of the front and rear surfaces of the lens body, refractive index of the lens body) to be changed independently of one another within relatively wide limits after implantation of the empty lens. After the intraocular lens has been folded into minimal dimensions in the posterior chamber of the eye, the filling material is introduced into the three filling bags 16a, 16b and 16c. In this case, the inner circular filling bag 16c is not completely filled. With the aid of objective refraction methods (refractometer, skiascopy, ..), the radius of curvature of the front surface 17a and the rear surface 17b of the lens body 17 can now be changed by changing the filling states in the inner circular filling bag 16b and in the inner circular filling bag 16c, regardless of the diameter of the final one Lens body, which is defined by the outer circular filling bag 16a, be changed intraoperatively until emmetropia is reached.

5, a filling device 32 with a filling agent reservoir 20 is present on each of the filling bags 16 described, which is connected via a filling tube 36 to a filling hole 18 in the filling bag 16.

The particular advantage of the last embodiment variant is that for the first time it is possible to automatically adjust the refractive power of the intraocular lens intraoperatively to the existing optical properties of the individual eye. A device which performs this intraoperative individual automatic emmetropization is shown in FIG. 6. The procedure is as follows:

First, the intraocular lens manufactured according to FIG. 4 is implanted in the collapsed state in the capsular bag of the eye 25 to be operated on. The three filling bags 16a, 16b, 16c are then pumped through the suction devices 32a, 32b and 32c via the filling tubes 36a, 36b. 36c filled with filling material so that the entire construction unfolds in the capsular bag 3. Then the deviation of the eye 25 from the emmetropic state is measured intraoperatively via the refractometer 30. Three cases can now be distinguished:

1. Emmetropia: If the eye is emmetropic, no manipulation of the filling status of the filling bags 16a, 161, 16c is required. The filling material is hardened by a cold light source and the eye 25 can be closed after the filling tubes 36a, 36b, 36c have been removed.

2. Myopia: If the refractive power of the intraocular lens is relatively high, the radius of curvature of the front surface 17a and rear surface 17b of the lens body 17 must be increased. The refractometer 30 forwards a signal suitable for the measured myopia to the control unit 31. This controls the two pump-suction devices 32b and 32c in such a way that a small amount of filling material is sucked out of the central filling bag 16b and a small amount is pumped into the inner circular filling bag 16c, so that the possible total volume of these two Filling bags 16b, 16c are filled again with filling material. Only the proportion of each of the two bags 16b, 16c in this total volume changes. This process is repeated until emmetropia is reached.

3. Hyperopia: If the refractive power of the intraocular lens is relatively too low, the radius of curvature of the front surface 17a and rear surface 17b of the lens body 17 must be reduced. The refractometer 30 transmits a signal suitable to the measured hyperopia to the control unit 31. This controls the two pump-suction devices 32b and 32c in such a way that a small amount of filling material is sucked out of the inner circular filling bag 16c and then a small amount of filling material is pumped into the central filling bag 16b, so that the possible total volume of these two filling bags 16b, 16c is filled again with filling material. This process is repeated until emmetropia is reached.

Any difference between the refractive index in the liquid (monomeric) state and the solid (polymeric) state of the filling material can be taken into account in the refractometer during the procedure described above.

Claims

PATENT CLAIMS

1. Artificial lens for implantation in an eye (25) with an optically effective lens body (7, 17) and a clamping device arranged essentially along the circumference of this lens body (7, 17), characterized in that the clamping device consists of at least one flexible hollow body (6, 16a, 16c) which can be filled with a medium after the implantation.

2. Artificial lens according to claim 1, characterized in that the hollow body (6, 16a, 16c) has a substantially toric shape in the filled state and is arranged in the region of the circumference of the lens.

3. Artificial lens according to one of claims 1 to 2, characterized in that the hollow body (6, 16a, 16c) has a filling hole (8) to which a filling tube (36a, 36c) can be attached.

4. Artificial lens according to one of claims 1 to 3, characterized in that the optically active lens body (7, 17) consists of an at least temporarily flexible medium and is surrounded by a dense shell (16b).

5. Artificial lens according to claim 4, characterized in that the hollow body (16c) is arranged in the interior of the envelope (16b).

6. Artificial lens according to one of claims 1 to 5, characterized in that the Hohl¬ body (6, 16a) on the outside of the lens body (7, 17) is attached.

7. Plastic lens according to one of claims 4 to 6, characterized in that the flexible medium after the implantation of the lens in the eye (25) in the envelope (16b) of the lens body (17) can be filled.

8. Plastic lens according to one of claims 4 to 7, characterized in that the inner space 26b) of the envelope (16b) of the lens body (17) is closed off from the inner space (26a, 26c) of the hollow body (16a, 16c) .

9. Device for changing the refractive power of an artificial lens according to one of claims 1 to 8, consisting of at least one suction pump device (32a, 32b, 32c). a device (30) for measuring the refractive power of the artificial lens and a control device (31). which controls the suction pump device (32a, 32b, 32c) as a function of the measured refractive power.

10. The device according to claim 9, characterized in that the Saug-Pumpeinrich¬ device (32a, 32c) via a filling tube (36a. 36c) with the hollow body (16a, 16c) can be connected.

11. The device according to claim 9 or 10, characterized in that a further suction pump device (32b) for connection to the sheath (16b) of the lens body (17) is seen vor¬.