WO2006016169A1

WO2006016169A1 - Ophthalmic prosthesis

Info

Publication number: WO2006016169A1
Application number: PCT/GB2005/003162
Authority: WO
Inventors: Dinesh Verma
Original assignee: Dinesh Verma
Priority date: 2004-08-11
Filing date: 2005-08-11
Publication date: 2006-02-16
Also published as: GB0417823D0; GB2416993A

Abstract

The present invention relates to an ophthalmic prosthesis comprising a lens portion for location over a central portion of the eye, the lens portion being carried by one or more radial support members extending radially away from the lens portion and capable of being bonded to an eye lid, the support members being effective when so bonded to lift the lens portion away from the cornea of the eye when the prosthesis is fitted.

Description

DESCRIPTION OPHTHALMIC PROSTHESIS

The present invention relates to an ophthalmic lens having a lens portion connected to supporting numbers that are capable of being bonded to the periphery of the eye for use in correcting eye deficiencies.

Refractive errors of the eye are one of the most common conditions affecting eyesight in millions of people around the world. Commonly, such errors are corrected by means of spectacles worn about a persons head or contact lens placed on the surface of a persons eyeball. Intraocular lens may also be used to treat refractive errors in addition to incisions in the cornea (radial keratotomy), however these techniques require complex surgical procedures which are invasive to the eyes. In recent times, lasers have also been employed to remove the cornea tissue and these include lasers treating the surface of the cornea (PRK (Photo Refractive Keratectomy)), lasers under surface (LASIK/Lasers In Situ Keratomileusis) and Epi PRK etc. All methods except spectacles carry the risk of permanent damage to vision due to their close contact with the eye. For example, contact lenes have been known to cause abrasions to the eye in addition to causing infections and ulcers to the cornea. Intraocular lenses and laser treatment of the eye require procedures which are all-invasive and therefore carry the risk of severe visual loss should the procedure not be successful. Therefore, there is a need to provide a ophthalmic lens for correcting refractive errors of the eye with a reduced risk of damage to the eye and will preferably be semi-permanent for the convenience of the user (by reducing the requirement of cleaning lenses on a

regular basis).

GB 2016736 discloses a corneal lens having a substantially circular optical correction zone and one or more lugs extending therefrom for engagement with depressions on the sclera of the eye ball which exist between the four ocular muscles attached thereto. Whilst this lens may assist in the formation of a lens for treating astigmatism, it also has a number of problems associated with it. Whilst this type of contact lens may address a number of problems associated with the prior art lenses, as the lens is manually inserted into the eye everyday, the eye may become scratched or infected due to the use of this lens.

US 5, 166, 710 discloses a contact lens having a supporting edge which rests on the sclera and is covered at least partially by both eye lids and absorbs the forces acting on the lens as the lid closes. The rear face of the lens in the region of the cornea is spaced from the surface of the cornea and the exchange of lachrymal fluid between the contact lens and the surface of the eye is provided for by channels which are provided on the lens, these channels also permit the lens to rotate whilst on the eye ball. This lens is not only complicated to manufacture, but the channels provided on the lens may become damaged or indeed act themselves as structures which may scratch the eye and therefore causing ulcers and/or infections. These channels may also become damaged easily requiring frequent replacement of the lens which could prove to be costly and/or require an increased input from the optician.

It is therefore an object of the present invention in order to alleviate one or more of the problems associated with prior art lens and devices used for correcting refractive errors in the eye. It is also an object of the present invention to provide an ophthalmic lens or prosthesis which is capable of being semi¬ permanently/permanently attached to the eye. Furthermore, it is also an object of the present invention to provide an ophthalmic lens which is not in direct contact with the cornea of the eye.

In accordance with the present invention, there is provided an ophthalmic prosthesis comprising a lens portion for location over a central portion of the eye, the lens portion being carried by one or more radial support members extending radially away from the lens portion and capable of being bonded to an eye lid, the support members being effective when so bonded to lift the lens portion away from the cornea of the eye when the prosthesis is fitted.

The present invention therefore provides an ophthalmic prosthesis which can be used for correcting refractive errors in the eye on a semi-permanent/or permanent basis, which does not damage or touch the cornea of the eye. Preferably, the support members are effective to retain the lens portion behind the eye lid when closed.

Advantageously therefore, the support members can be deformed in a manner appropriate to keeping the lens behind the eye lid during, for example, blinking.

The support members will preferably be flexible or semi-flexible and/or foldable. The flexibility will permit the prosthesis to be comfortable when in place and whilst the eye lids cover the members. Flexibilty will also permit the lens portion to resume its normal position relative to the cornea if the support members are subjected to external forces.

The support members may be bonded to the eye lid by means of a tissue adhesive/glue. Preferably, at least one support member is bonded to the inner surface of the eye lid. The inner eye lid should be construed as the part of the eye lid in contact with the sclera or conjunctiva. An example of a suitable tissue adhesive may be histoacrylate. Alternatively, the support members may be bonded to the eye lid by means of sutures or clips (or indeed a similar mechanical means of attaching the support members to the periphery of the eye lid). .The support members may be elongate and may additionally terminate in pads. The pads of the support members may be bonded to the eye lid (by means of a tissue adhesive or mechanical means). Two or more pads may be joined by a spacing element and it would be apparent to one skilled in the art that such a spacing element may assist in providing structural rigidity to the support members in addition to allowing the support members to be bonded to the eye lid. Preferably, there are four support members, however it is envisaged that any number of support members may be used in accordance with the present invention. The spacing elements may join two support members along the plane corresponding to the eye lids. The support members may be divided into upper support members and lower support members, such that the upper support members are for bonding the lens to the upper eyelid and are more rigid. The lower support members may be less rigid and flexible and rest between the white of the eye and the lower eye lid. Alternatively, the lower support members may also be bonded to the lower eye lids for bonding the upper eye lid.

The support members and/or lens portion may be manufactured from different materials such as those chosen on the basis of their functionality and characteristics (such as a highly refractive material used for the lens portion and a suitably semi-rigid material for the support members). Alternatively, the support members and the lens portion may be manufactured from the same material. The prosthesis material may be releasably connected to the support members so as to permit lens of a higher or lower refractive index to be bonded to the eye in order to accommodate changes in an ophthalmic prescription. Preferably, the lens portion is maintained at least 5 - 100 microns from the cornea, so as to allow the access of oxygen and tears.

The prosthesis may be used to correct a number of refractive errors in the eye such as myopia, hypermyopia, hypermetropia, astigmatism, presbyopia, mixed astigmatism, aphakia, pseudophakia, and any type of under or over correction of refractive errors and any aberropias. Preferably, the lens portion has an optical zone defined by its refractive index. The lens portion may also be substantially circular and may be a size similar to that of the cornea, but may equally be larger or smaller than the cornea. Also, a centre portion of said lens portion may be substantially circular, elliptical, oval, quadrangular, or any variation thereof, in shape. The prosthesis may at least be partially manufactured from a plastics material which may or may not be selected from one or more of the following materials; Polymethylmethacrylate (PMMA), silicone, hydromethylacrelate (HEMA), hydrogel, hydrophobic acrylic, hydrophilic acrylic or derivatives thereof. The material may also have an amniotic membrane cover for the lens and/or the support members.

The present invention will now be described by way of example only and with reference to the following example and associated figures.

Figure 1 shows an ophthalmic prosthesis in accordance with the present invention bonded to an eye; Figure 2 is a cross-section cutaway diagram of the prosthesis as shown in Figure

1;

Figure 3 is a cross-section cutaway diagram of the prosthesis of Figure 1, but with the eyelid of the user in a closed position; and

Figures 4a-4c are cross-sections of an ophthalmic prosthesis in accordance with the present invention, bonded to the eye lids by different methods.

With reference to both Figures 1 and 2, there is provided an ophthalmic prosthesis which is suspended adjacent to, and away from the cornea (4) by means of four elongate members (6) radially extending from a lens (2), the elongate members having two upper members (8, 10) that are attached to the upper eye lid (12) by means of pads (14). Both the upper members (8, 10) and the lower members are connected by a bridge (16) which acts to maintain the pads (14) away from one another in the correct special configuration. The pads of the lower members are not bonded to the lower eye lid (18) but are merely received in the space between the eye ball and the lower eye lid (18).

The upper support members (8, 10) are permanently (or semi-bonded) to the upper eye lid (12) by means of a tissue adhesive such as histoacrylate, but may also be bonded by mechanical means, such as with sutures or a clip, or indeed both an adhesive and a mechanical means. The lens (2), elongate members (6), pads (14) and bridge (16) can be formed from a one-piece construction using the same material such as a plastics material or silicone. Other materials may also be used to produce the prosthesis and indeed the lens (2) may also be produced from a different material to the elongate support (6), pads (14) and bridge (16).

Commonly, the upper support members (8, 10) will be rigid whereas the lower support members will be more flexible. Indeed, such an arrangement is illustrated in Fig. 3, which shows the prosthesis in-situ with the eyelids in a closed position. As can be seen from Fig. 3, when the eyelids are closed, the prosthesis is arranged to rest under the lower eyelid. The provision of rigid upper support members (8, 10) with flexible lower members (20) allows the prosthesis to rest under the lower eyelid when the user is sleeping (or during blinking or any other act of closing the eyelids).

With reference to Figures 4a-4c there are provided a number of configurations for attaching the ophthalmic prosthesis to an eye lid. In Figure 4a, the upper support member (40) is attached to the interior surface of an eye lid (42) by means of a suture (44) which is disposed through the width of the eye lid (42). In Figure 4b, a support member (50) is bonded to an eye lid (52) by means of a layer of histoacrylate adhesive (54). In Figure 4c, a support member (60) has been physically inserted into an eye lid (62) and is held in the insertion in the eyelid (62) by means of a histoacrylate adhesive (64). As can be clearly seen in Figure 2, when in place, the ophthalmic prosthesis allows for the lens (2) to be spaced apart from the cornea (4) whilst allowing air and fluid (such as lachrymal fluid) to pass therebetween as and when required. This is a great advantage over the prior art contact lens and procedures as the ophthalmic prosthesis can be permanently/semi-permanently placed upon the eye, whilst allowing oxygen and fluid to pass behind the lens (2) and the cornea (4) such that the prosthesis does not need to be removed on a regular basis or any invasive surgery required to place the ophthalmic prosthesis in position. The lens (2) can also be releasably attached to the supporting members (6) such that the refractive index of lens (2) and/or the material of lens (2) can be replaced if necessary. Due to the flexibility of the lower supporting members (6), when the eye lids are open, the lens (2) will be in the correct position relative to the cornea (4) as when the lids are closed, would allow the prosthesis to go behind the lower lid without touching the cornea. The prosthesis may be removed from the eye by a number of methods such as physically removing the prosthesis by means of a scalpel, but alternatively it may be removed by means of a solvent which dissolves the adhesive which is non-toxic to the human or animal body.

In the above embodiments, the prosthesis is shown with a lens portion (optic) which is substantially circular in the centre. However, this central portion of said lens portion may also be elliptical, oval, quadrangular, or any variation thereof.

Claims

1. An ophthalmic prosthesis comprising a lens portion for location over a central portion of the eye, the lens portion being carried by one or more radial support members extending radially away from the lens portion and capable of being bonded to an eye lid, the support members being effective when so bonded to lift the lens portion away from the cornea of the eye when the prosthesis is fitted.

2. An ophthalmic prosthesis as claimed in Claim 1, wherein the support members are effective to retain the lens portion behind the eye lid when closed.

3. An ophthalmic prosthesis as claimed in Claim 1 or 2, wherein the support members are flexible or foldable.

4. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the support members are bonded to the eye lid with tissue adhesive.

5. An ophthalmic prosthesis as claimed in Claim 4, wherein the tissue adhesive comprises histoacrylate.

6. An ophthalmic prosthesis as claimed in any one or more of Claims 1 to 4, wherein the support members are bonded to the eye lid by means of sutures or

clips.

7. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the support members are bonded to the inner surface of the eye lid.

8. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the support members are elongate.

9. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the support members terminate in pads.

10. An ophthalmic prosthesis as claimed in Claim 9, wherein the pads of support members are bonded to the eye lid.

11. An ophthalmic prosthesis as claimed in Claim 9 or 10, wherein the two or more pads are joined by a spacing element.

12. An ophthalmic prosthesis as claimed in Claim 11, wherein there are four or more support members.

13. An ophthalmic prosthesis as claimed in Claim 12, wherein the spacing elements join two pads together.

14. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the support members and lens portions are manufactured from different materials.

15. An ophthalmic prosthesis as claimed in any one or more of Claims 1 to 13, wherein the support members and lens portions are manufactured from the same material.

16. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the lens portion is releasably connected to the support members.

17. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the lens portion is maintained at least 100 microns from the cornea.

18. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the prosthesis is used to correct myopia, hypermyopia, hypermetropia, astigmatism, presbyopia, mixed astigmatism, aphakia, pseudophakia, or any type of under or over correction of refractive errors.

19. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the lens portion has an optical zone defined by its refractive index.

20. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the lens portion is substantially circular in shape.

21. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein a centre portion of said lens portion is substantially circular in shape.

22. An ophthalmic prosthesis as claimed in any one or more of the Claims 1 to 20, wherein a centre portion of said lens portion is substantially elliptical in shape.

23. An ophthalmic prosthesis as claimed in any one or more of the Claims 1 to 20, wherein a centre portion of said lens portion is substantially oval in shape.

24. An ophthalmic prosthesis as claimed in any one or more of the Claims 1 to 20, wherein a centre portion of said lens portion is substantially quadrangular in shape.

25. An ophthalmic prosthesis as claimed in any one or more of the preceding claims, wherein the prosthesis is at least partially manufactured from a plasties material.

26. An ophthalmic prosthesis as claimed in any one or more of Claims 1 to 24, wherein the prosthesis is at least partially manufactured from one or more of the following materials: poly methacrylate, silicone, hydromethylacrylate, hydrogel, hydrophobic acrylic, hydrophilic acrylic or derivatives thereof.

27. An ophthalmic prosthesis as hereinabove described with reference to and as illustrated in the accompanying Figures.