An intraocular implant for placement in the eye, e.g. as part of a cataract operation or crystalline lens extraction refractive operation, has at a peripheral portion (54) of the implant a groove (56,62,63,66,67) which engages with the lip of a single capsulotomy only formed in the lens capsule of the eye. The implant will normally be a lens (52,70,94), but may instead be a bung or plug for occluding an opening made in the capsule. The groove may be a continuous groove around the periphery of the implant, or there may be a series of individual spaced-apart grooves formed as projections protruding from the periphery. Instead of a single groove, a pair of axially spaced-apart grooves may be provided, which engage with respective capsulotomies formed in an anterior and a posterior part of the capsule. The posterior groove is preferably of a smaller mean diameter than the anterior groove.
