Abstract: A tissue barrier (10), for example of titanium alloy, for insertion into an incision in sclera of the eye for the treatment of conditions such as presbyopia, comprises an elongate body which is inert and/or non-reactive in tissue. The barrier can include lateral flanges (14) or not. In a preferred embodiment the barrier has an inverted T-shaped cross-section.

Abstract: A knife for ophthalmic surgery has a diamond blade (14) which protrudes at the forward end of a handle (11) through a slot in a footplate (16). The surface of the footplate which contracts the tissue (cornea or sclera, for example) to be incised has irregular castellations (28a, 28b, 28c, 28d, 28e, 28a′, 28b′, 28c′, 28d′, 28e′) forming irregular grooves (32a, 32b, 34a, 34b, 32a′, 32b′, 34a′, 34b′) therebetween. Alternatively or in addition, the contact surface has protruding pins (140) which engage the tissue (sclera, usually) to be incised.