GB2240927A

GB2240927A - A donor eye stand

Info

Publication number: GB2240927A
Application number: GB9003587A
Authority: GB
Inventors: Israel Narh Nartey
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-02-16
Filing date: 1990-02-16
Publication date: 1991-08-21
Anticipated expiration: 2010-02-16
Also published as: GB9003587D0; GB2240927B

Abstract

A stand for supporting a donor eye during the excision of a corneoscleral button or cornea disc comprises a base plate (1) presenting an upstanding spindle (7) upon which a main body (8) having an externally threaded cylindrical projection (15) is rotatably supported. A donor eye placed on an eye support block (17) lodged in the main body projection (15) is clamped by means of a clamping unit (30) comprising an internally threaded clamping cylinder (31) one end of which is screwed onto the main body extension (15) and a clamping ring which is screwed into the other end of the clamping cylinder (31). The main body can be locked to the spindle (7) by a locking pin (12) and the clamping cylinder (31) can be locked to the main body (8) by a thumbscrew (40). <IMAGE>

Description

Description of Invention "A donor eye stand" THIS INVENTION relates to stand for supporting a donor eye during the excision of a corneoscleral button or corneal disc from the eye.

It is known to provide a stand for supporting and clamping a donor eye to facilitate the operation of cutting from the eye a corneoscleral button to be stored or a corneal disc for keratoplasty.

Both adult and neonatal donor eyes are used as a source of such buttons and discs. The cornea of an infant donor eye is, however, difficult to handle because of its flexibility and tendency for the tissue to fold over on itself. This predisposes the endothelium of the donor eye to the risk of damage.

Currently available commercial donor eye stands have been designed primarily to accommodate adult donor eyes and, although such known eye stands can be modified to fit infant donor eyes, this does not result in the donor eye being satisfactorily supported by the clamping means of the eye stand.

Given the limitations of the existing eye stands, some practitioners have resorted to the alternative of wrapping the very young donor eye in gauze and holding the eye by hand whilst a corneoscleral button is removed from the eye. This hand-held approach requires great skill and, even then, yields very imprecise results.

The present invention aims to provide a donor eye stand which can be used to obtain corneoscleral buttons and corneal discs from both infant and adult donor eyes.

Accordingly, the present invention provides a stand for supporting a donor eye during the excision of a corneoscleral button or corneal disc, comprising a base provided with an upstanding spindle, a main body which has an axial bore for receiving the spindle to mount the main body on the base for rotation about the axis defined by the spindle and which comprises an externally threaded axially extending cylindrical projection defining a socket having a floor at its lower end and an open upper end, an eye support block to be received in the socket with a lower end thereof standing on the floor and with an upper end projecting from the open end of the socket, the upper end of the support block being concavely shaped to support a donor eye placed thereon, and a clamping unit having a through bore which is internally threaded at one end to cooperate with the external thread on the cylindrical projection of the main body to draw the clamping unit down onto an eye supported on the eye support block in the support socket, so as to clamp the eye with a portion thereof projecting from the other end of the bore of the clamping unit.

Preferably, the clamping unit comprises a clamping sleeve having a bore with a first portion threaded to cooperate with the cylindrical projection of the main body and a second portion adapted to cooperate with an externally threaded skirt on a clamping ring.

Advantageously, the second portion of the bore of the clamping sleeve has a larger diameter than the first portion of the bore, so that a ledge is formed in the bore for locating a removable disc receivable in the bore to serve as a support for a block of resilient material on which is placed a corneoscleral button from which a corneal disc is to be punched from the endothelial surface.

Conveniently, the eye support block has an axially extending hole therein for accommodating an optic nerve stump of the donor eye placed on the eye support block.

Preferably, the axially extending hole in the eye support block is threaded to receive a threaded manipulating pin by which the eye support block can be introduced into and removed from the socket of the main body.

The base plate may be provided with a storage hole in which the manipulating pin may be kept when not in use.

The main body may be locked against rotation by a locking screw extending transversely through the main body and engageable with the spindle.

In a preferred embodiment, a knurled thumbscrew extending transversely through the clamping unit enables the clamping unit to be locked to the main body when a desired position is reached.

Desirably, a friction-reducing disc is provided between the base and the main body.

In order that the present invention may be more readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawing, in which the single Figure is an exploded side view, showing hidden detail, of a donor eye stand embodying the invention.

Referring firstly to Figure 1, a donor eye stand embodying the present invention comprises a circular base plate 1 having an upper surface 2. A threaded bore 4 extends centrally into the base plate 1 from the upper surface 2 thereof and a threaded shank 5 of a locating pin 6 is screwed into the bore 4. A cylindrical head 7 of the pin 6 forms a fixed spindle upon which a main body 8 of the stand is rotatably mounted by engagement of the spindle 7 in a mounting bore 9 formed in a cylindrical base portion 10 of the main body 8. A friction reducing washer 3 is disposed between the base 1 and the base portion 10 of the main body.The base portion 10 of the main body 8 has a smooth cylindrical surface and is formed with a screw threaded radial bore 11 for receiving a screw threaded locking pin 12 having a head 14 by which the pin may be rotated into engagement with the spindle 7 in order to lock the main body against rotation.

An externally screw threaded cylindrical projection 15 extends upwardly from the base portion 10 of the main body 8 and is of smaller diameter than the base portion 10. The projection 15 defines therein a socket 16 for snugly receiving a cylindrical eye support block 17 with a planar lower end 18 of the support block 17 standing on a floor 19 formed at the lower end of the socket 16 and an upper concavely shaped end 20 of the support block 17 projecting from the open end 21 of the socket. A threaded hole 22 extends through the block 17 between the ends 18 and 20 and serves to accommodate an optic nerve stump of a donor eye placed on the concave end 20 of the support block.

Two interchangeable eye support blocks 17 are supplied with the eye stand, a shorter one of the blocks being intended for use with adult donor eyes and a longer block being intended for use with infant donor eyes.

A threaded manipulating pin 25 which is knurled at one end is adapted to engage the screw threaded hole 22 in the eye support block 17 and can be used to lift the latter out of the main body 15. When not in use, the manipulating pin 25 may be stored in a blind storage hole 26 provided for this purpose in the base plate 1.

A clamping unit 30 for clamping a donor eye placed on the eye support 17 comprises a clamping sleeve 31 having a knurled cylindrical surface 32 and a screw threaded through bore 33 comprising a first deeper portion 34 and a second shallower portion 35. The first portion 34 of the bore 33 is of smaller diameter than the second portion 35, so that an annular ledge 36 is formed within the bore 33.

The first portion 34 of the screw threaded bore 33 is adapted to cooperate with the externally threaded projection 15 of the main body 8 and the second portion 35 is adapted to cooperate with an externally threaded skirt 37 on a clamping ring 38 having an aperture 39 through which the cornea and a rim of sclera of the donor eye project as the clamping unit 30 is screwed home onto the main body. The aperture 39 has a chamfered rim.

Two interchangeable clamping rings 38 may be provided, one with a smaller central aperture for use with infant donor eyes and another with a larger aperture for use in obtaining larger corneoscleral buttons from adults, although the clamping ring intended for infants may also be used for adult donor eyes in suitable circumstances. The clamping unit 30 acts as an intraocular pressure adjuster which applies increasing compression to the donor eye as the clamping unit 30 is screwed onto the main body 8.

A thumbscrew 40 is received in a transverse passage 41 in the clamping sleeve 31 for tightening into engagement with the main body projection 15 to lock the sleeve 31 to the main body 8 when the pressure on the donor eye is judged to be satisfactory.

With the clamping ring 38 and the eye support block 17 removed, a metal disc (not shown) may be placed in the threaded bore 35 so as to rest on the ledge 36. The metal disc acts as a platform for a "Teflon" (Registered Trade Mark) block for supporting a corneoscleral button from which a cornescleral disc is to be punched from the endothelial side of the button.

To prepare a corneoscleral button from an infant donor eye for storage using the described donor eye stand, the main body 8, the longer eye support block 17 and the clamping sleeve 31 are assembled on the base plate 1 and locked against rotation by means of the locking pin 12.

The donor eye is cleansed and placed on the end 20 of the eye support block 17 with the optic nerve stump extending into the bore 22 of the support block. The clamping ring 38 is then screwed home and, provided that the clamping sleeve 31 has not engaged more than about half of the threads on the main body projection 15, the clamping ring 38 will still be clear of the surface of the cornea. By carefully screwing the clamping unit 30 home using the thumbscrew 40 to rotate the sleeve 31, the cornea and a generous rim of sclera will protrude through the aperture 39 in the clamping ring 38. When a suitable pressure is judged to have been attained, the thumbscrew 40 is tightened to lock the sleeve 31 to the main body 8 and the locking pin 12 is released.Rotating the assembly around the spindle 7 by means of the locking pin 12 with the eye engaged with a sharp blade allows a simple and atraumatic removal from the donor eye of a corneoscleral button at a constant pressure.

To remove a corneoscleral button from an adult donor eye, the same procedure is carried out as for the infant donor eye, except that the shorter eye support block 17 and the clamping ring 38 with the larger aperture 39 are used.

The longer eye support block 17 may, however, be used for adult donor eyes, provided the clamping sleeve has not engaged more than two-thirds of the threads on the main body projection 15. If the clamping ring 38 cannot be screwed home over the donor eye, the clamping sleeve 31 may be unscrewed slightly to clear the surface of the cornea. The clamping ring 38 is then screwed home. Which clamping ring 38 is used for the adult donor eye depends on how large a corneoscleral button is required. The clamping ring 38 with the larger aperture cannot, however, be used for the infant donor eye.

Whilst the clamping unit 30 of the donor eye stand described above has a clamping unit 30 of two-part construction it is envisaged that the clamping unit could be of integral construction with the clamping sleeve 31 and clamping ring 38 formed as a single component.

To cut a penetrating or lamellar disc from a donor eye, the eye is placed in the same assembly as for obtaining a corneoscleral button. A forceps is used to centre the donor eye on the central axis of rotation and, when a suitable tension for trephining or lamellar dissection is judged to have been reached, the thumbscrew 40 on the clamping unit 30 is tightened. Lamellar dissection or trephination can then be carried out in the conventional manner at a constant pressure. After the anterior chamber has been entered, if the trephine is incomplete it may then be completed using a suitable sharp blade or scissors. The clamping unit 30 and the main body 8 can be rotated as a single unit in a controlled manner during the precedure using the released locking pin 12.

To punch a penetrating donor disc from the endothelial surface of a corneoscleral button, the main body 8 and the clamping sleeve 31 of the clamping unit 30 are assembled without the eye support block 17 and the clamping ring 38 and non-rotatably locked with the locking pin 12. The clamping sleeve 31 is screwed home to the fullest extent on the main body projection 15 and its thumb-screw 40 tightened. The metal support disc is placed in the bore 35 so as to rest on the ledge 36 and a platelike "Teflon" (Registered Trade Mark) block with a concave upper surface is then rested on the metal disc.

The corneoscleral button is then centred on the "Teflon" (Registered Trade Mark) block with its endothelial surface uppermost and punched with a hand-held trephine.

Claims

CLAIMS:

1. A stand for supporting a donor eye during the excision of a corneoscleral button or corneal disc, comprising a base provided with an upstanding spindle, a main body which has an axial bore for receiving the spindle to mount the main body on the base for rotation about the axis defined by the spindle and which comprises an externally threaded axially extending cylindrical projection defining a socket having a floor at its lower end and an open upper end, an eye support block to be received in the socket with a lower end thereof standing on the floor and with an upper end projecting from the open end of the socket, the upper end of the support block being concavely shaped to support a donor eye placed thereon, and a clamping unit having a through bore which is internally threaded at one end to cooperate with the external thread on the cylindrical projection of the main body to draw the clamping unit down onto an eye supported on the eye support block in the support socket, so as to clamp the eye with a portion thereof projecting from the other end of the bore of the clamping unit.

2. A donor eye stand according to claim 1, wherein the clamping unit comprises a clamping sleeve having a bore with a first portion threaded to cooperate with the cylindrical projection of the main body and a second portion adapted to cooperate with an externally threaded skirt on a clamping ring.

3. A donor eye stand according to claim 2, wherein the second portion of the bore of the clamping sleeve has a larger diameter than the first portion of the bore, so that a ledge is formed in the bore for locating a removable disc receivable in the bore to serve as a support for a block of resilient material on which is placed a corneoscleral button from which a corneal disc is to be punched from the endothelial surface.

4. A donor eye stand according to any one of claims 1 to 3, wherein the eye support block has an axially extending hole therein for accommodating an optic nerve stump of the donor eye place on the eye support block.

5. A donor eye stand according to claim 4, wherein the axially extending hole in the eye support block is threaded to receive a threaded manipulating pin by which the eye support block can be introduced into and removed from the socket of the main body.

6. A donor eye stand according to claim 5, wherein the base plate is provided with a storage hole in which the manipulating pin may be kept when not in use.

7. A donor eye stand according to any preceding claim, wherein the main body may be locked against rotation by a locking screw extending transversely through the main body and engageable with the spindle.

8. A donor eye stand according to any preceding claim, wherein a knurled thumbscrew extending transversely through the clamping unit enables the clamping unit to be locked to the main body when a desired position is reached.

9. A donor eye stand according to any preceding claim, wherein a friction-reducing disc is provided between the base and the main body.

10. A donor eye stand substantially as hereinbefore described with reference to the accompanying drawing.

11. Any novel feature or combination of features described herein.