US20030093132A1 - Retinal implant with improved implantation and working properties - Google Patents

Abstract

The invention relates to a retinal implant having at least one functional unit4positioned internally inside an eye and at least one functional unit (2) positioned externally outside the eve and at least one functional unit8position outside the eye, which are separably connected to one another via a signal path (5, 6, 7, 15, 16, 17; 10, 11, 12, 15, 16, 17) in a manner designed for signal or data transmission. The patient's residual vision which may still remain is preserved because the signal path extends through the sclera (9) of the eye and does not incorporate the anterior eye section.

Description

• The present invention relates to a retinal implant having the features of the precharacterising clause of claim 1.[0001]
• An implant according to the generic type is known from U.S. Pat. No. 5,935,155. This document proposes that a functional unit (IGF) positioned inside the vitreous chamber be connected to an externally positioned functional unit (EPF) via wireless coupling of two coils. The coil of the internal functional unit is in this case arranged in the lens behind the iris.[0002]
• In addition to the surgical intervention on the vitreous body for implanting the functional unit (IGF) positioned inside the vitreous chamber, a second surgical intervention is necessary in the anterior eye section for implanting the coil or a second functional unit (AGF) positioned outside the vitreous chamber (especially in the lenticular capsule in place of the intraocular lens (IOL), which needs to be removed before-hand).[0003]
• The second functional unit (AGF), which is implanted in the lenticular capsule and is provided, in particular, in the case of various retinal implants, is mechanically connected to the IGF via a microcable and, in currently available versions, cannot be temporarily separated and re-connected. Technical solutions for this are, however, available. This mechanical connection makes the surgical interventions significantly more difficult since, when implanting the AGF in the lenticular capsule envelope, it is also necessary to make an opening in the lenticular capsule wall and to transfer the IGF, with the microcable connection, through this opening into the vitreous chamber. This entails additional risk factors such as: mechanical destabilisation of the lenticular capsule envelope by the additional opening; mechanical stress on the implant components, including the microcable; lengthening of the implantation time; increase in the risk of future pathological tissue changes, which may make the implant function or further surgical interventions (such as e.g. re-explantation) difficult or impossible.[0004]
• Positioning the AGF in the anterior eye segment significantly restricts optical access to the retina and to the IGF. This can have a detrimental effect both on the function of the implant system and on sight, as well as on the medical inspectability of the vitreous chamber.[0005]
• Externally positioned functional units (EPF) located outside the body are positioned immediately in front of the eye, in the normal field of view of the eye, in place of a spectacle lens or a contact lens, and hence impede any partial sight which may still remain (e.g. in subjects with macular degeneration and remaining extrafoveal vision).[0006]
• As the signal processing effort rises, especially in the case of retinal implants, when the number of microcontacts increases, the mass and energy demand of the microelectronic components rises significantly, so that in this context a limit for intraocularly implantable functional units is rapidly reached and the desired functional quality of the implant is thereby substantially restricted.[0007]
• It is therefore an object or the present invention to provide a retinal implant in which the connection between the internal functional unit IGF and at least one external functional unit (AGF, EPF) does not interrupt the optical path between the lens and the extrafoveal region of the retina, and in which this connection is wireless or can be mechanically separated during implantation.[0008]
• This object is achieved by a retinal implant having the features of claim 1. Because the signal path extends through the sclera of the eye, inside the eye socket bounded by the conjunctiva, the optical path from the lens to the retina outside the foveal region remains free. The separability of the signal path permits separate implantability of the component implanted inside the eye and the component implanted outside the eye in the eye socket.[0009]
• Advantageous embodiments are given in the dependent claims.[0010]
• Two exemplary embodiments of the present invention will be described below with reference to the drawing, in which:[0011]
• FIG. 1 shows an implant with a wireless inductive connection between the internal functional unit and a second functional unit implanted outside the eye;[0012]
• FIG. 2 shows a similar implant to FIG. 1, with a separable plug connection between the internal functional unit and a second functional unit implanted outside the eye; and[0013]
• FIG. 3 shows a perspective representation of the implant according to FIG. 1[0014]
• FIG. 1 represents a retinal implant or patients having a degenerative disease of the retina[0015]1, in which the functional unit (EPF)2 present outside the body is positioned in the head region (e.g. on the side of a spectacle frame with normal spectacle function), in such a way that the optical beam path between viewed objects and the retina1 is impaired neither by functional units directly in front of the eye nor by functional units in the anterior eye segment, including the intraocular lens (IOL)3, and in such a way that, in particular, patients can thereby use their residual vision which may still remain (e.g. in the extrafoveal field of view in the case of macular degeneration), in addition to the implant function.
• In a retinal implant according to the invention, the functional unit IGF[0016]4 positioned inside the vitreous chamber is designed as a microcontact foil having associated microelectronics, amicrocable5 and at least one coil6, and is fastened close to the retina in a suitable way. Via this coil6 as part of the IGF4 and at least onecorresponding coil7 as part of the AGF8 inside the eye socket, a communication connection is made inductively through the sclera9. Since the signal path through the sclera9 of the eye extends inside the eye socket bounded by theconjunctiva19, the optical path from the lens to the retina outside the foveal region remains free. The separability of the signal path permits separate implantability of the component implanted inside the eye and the component implanted outside the eye in the eye socket.
• FIG. 2 illustrates another embodiment of a retinal implant according to the invention. In this case, the transscleral connection between the IGF[0017]4 and the AGF8 is made galvanically via amicrocable10, the microcable being mechanically separated at a plug connection11 during implantation, and the connection being made subsequently. Such amicrocable connection10 which can be made subsequently between the IGF4, which e.g. performs only retinal stimulation, and an AGF8 which undertakes decoder and/or demultiplexing functions, and which is implanted but located outside the eye, may preferably be configured in such a way that, according to the ophthalmological state of the art, a suitabletransscleral cannula12 is permanently implanted, themicrocable10 is fed through it, and the passage is sealed afterwards. The subsequentmicrocable connection10 may furthermore be designed in such a way that the two ends to be galvanically connected (corresponding to a male or female plug connector) carry an equal number of complementarily shaped metal contacts (e.g. as pins at one cable end and as sockets at the other cable end) which, during the separate implantation of the IGF4 and the AGF8, are covered with an insulating thin plastic film for protection against the effect of fluids.
• In a preferred embodiment, the microcable connection is established in that the pin part[0018]11 and the socket part11′ are positioned flat facing one another while aligning the rows of pins and corresponding sockets, and in that the pin part and the socket part can thereupon be pressed cleanly against one another in such a way that, on the one hand, the insulating film is pierced and, on the other hand, securely insulated galvanic connections of the correspondingmicrocable lines10 are made even under wet environment constraints
• In a preferred embodiment, this microcable connection can subsequently be re-separated by a suitable separating tool.[0019]
• This separable microcable connection, consisting of the pin part[0020]11 and the socket part11′, can preferably be produced both outside the eyeball in the eye socket (see FIG. 2) and inside the vitreous chamber (no image).
• In likewise advantageous embodiments, the wireless transscleral communication is produced optoelectronically or by ultrasonic transmitter and receiver pairs on both sides of a circumscribed scleral zone.[0021]
• In another embodiment, a[0022]cannula12 is arranged in the wall of the sclera9 according to the ophthalmological state of the art, and is shut off by a permeable film in the manner of a closed window.
• In another embodiment, the AGF[0023]8 is fastened sclerally to the outer wall of the bulb according to the ophthalmological state of the art (adhesive bonding, pinning or suturing) and has, in addition to amicrocable5 and at least oneprimary coil7 fastened sclerally facing the respective corresponding coil6 in the vitreous chamber, afurther microcable15 for connection to the functional unit (EPF)2 located outside the body.
• In a preferred embodiment, the connection between the AGF[0024]8 in the eye socket and theexternal EPF2 is made inductively via acoil pair16,17 and associated transmission andreception electronics18, thiscoil pair16,17 being separated by a skin region in the head area (e.g. on the forehead) and themicrocable15 from the AGF8 to thesecondary coil16 and thereception electronics18 of this preferably transcutaneous inductive connection being laid under the skin according to the surgical state of the art.
• In another possible version, the connection between the AGF[0025]8 in the eye socket and theexternal EPF2 is made via a suitable catheter structure and/or cable structure (not shown).
• In an advantageous embodiment, in order to set up a function outside the normal implant operation, optical and/or optoelectronic communication is produced between a functional unit located outside the body and the IGF[0026]4 in the vitreous chamber.
• The external[0027]functional unit2, which may comprise an encoder as well as camera means, may also, in one embodiment according to the invention, be worn by the patient in a manner other than with the conventional spectacle-type arrangement. For instance, the requisite components may also be arranged in a cap or a headband, which make it possible to avoid wearing spectacles which may be uncomfortably heavy. This furthermore permits the use of larger components, which are suitable for processing a larger number of optical channels or pixels.

Claims (6)

1. Retinal implant having at least one functional unit4 positioned internally inside an eye and at least one functional unit2 positioned externally outside the eye, which are connected to one another via a signal path (5,6,7,15,16,17;10,11,12,15,16,17) in a manner designed for signal or data transmission, characterised in that the transscleral signal-path segment between the functional units (4,8) can be separated, and in that the signal path between the functional units (2,4) does not incorporate the anterior eye section, including the cornea and intraocular lens.

2. Implant according toclaim 1, characterised in that the signal path comprises a wireless inductive connection (6,7) which has a respective transmission and reception element inside (6) and outside (7) the eye, which are arranged facing one another, the sclera (9) lying between the transmission and reception elements (6,7).

3. Implant according toclaim 1, characterised in that the signal path comprises a galvanic connection (10,11,11′) which passes through the sclera.

4. Implant according toclaim 3, characterised in that the galvanic connection (10,11,11′) can be connected after implantation, and preferably disconnected, at mutually complementary contact elements (11,11′).

5. Implant according to one of the preceding claims, characterised in that the sclera (9) is penetrated by a cannula (12) which is used for feeding an electrical cable (10) through.

6. Implant according to one of the preceding claims, characterised in that a functional unit (8) implanted outside the eye, which is designed to carry out signal processing functions, is provided.

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