Patent GB-1044420-A (GB)
Title: Artificial corneal implants
IPC: A61F2/14
Filed: 1965-05-11
Abstract: 1,044,420. Eye surgery. W. STONE. May 11, 1965 [May 25, 1964], No. 19783/65. Heading A5R. A corneal implant, which is marginally located between anterior and posterior corneal layers, includes a concavo-convex holding member having a central opening extending therethrough and a plurality of passages adjacent its periphery through which corneal stroma may grow and so permanently anchor the implant, and a lens member removably held in the opening. In one embodiment of the invention, Fig. 2, the holding member 21 is situated between anterior layer 19 and posterior layer 20 of the cornea 15 which protrudes slightly from the remainder of the eyeball to define limbus 16. The holding member has marginal holes 22 to permit anchoring ingrowth of stroma and a central portion 23 which extends inwardly into chamber C containing aqueous humour and separating the cornea from the lens 17 and iris 18. The lens member 26 comprises a head 27 and a shank 28 threaded for entry into the threaded opening 24 extending through the central portion of the holding member, the head of the lens fitting into recess 25 at the anterior end of the central portion. The flat underside 29 of the head of the lens has a marginal recess 30 for an O-ring seal 31 to enable the lens to be held by the holding member in leak-tight relationship. The head of the lens member is provided with recesses 32 for engagement of a tool to connect or separate the lens and holding member. The lens member as shown is a temporary lens, being held in place by sutures 33, and may be replaced by a further temporary lens after trephining the central portion of the anterior corneal layer. This lens, the head of which projects sufficiently to block anterior corneal growth, may be replaced by a permanent lens which conforms generally to the outer surface of the cornea and which has lens surfaces at both its anterior and posterior ends. In another embodiment of the invention, Fig. 9 (not shown), the central portion of the holding member extends outwardly for a distance sufficient to prevent growth in the central portion of the anterior corneal layer. The head of the lens member overlies the anterior portion of the central portion of the holding member, an O-ring seal ensuring leaktight relationship between the lens and the holding member. After trephining the central portion of the posterior corneal layer, the lens may be replaced by a permanent lens which conforms generally to the outer surface of the cornea, which extends inwardly into chamber C, and which has lens surfaces at both its anterior and posterior ends. Bayonet joints between, or friction fits of, the lens member and holding member may replace the threaded joints. The lens member must be of a material that is sufficiently clear for optical purposes, at least the portion of the holding member provided with anchoring passages must be of a material that is tolerated by corneal stroma, and the lens member, holding member and seal must be of a material that is inert with respect to aqueous humour. The material of the lens member, which may be glass or plastics, may be the same as or may differ from that of the holding member, which may be glass, plastics or suitably inert metals.