A prosthesis for scleral expansion includes a central body portion and at least one end portion having a width greater than the width of the central body portion. The end portion therefore inhibits rotation of the prosthesis about a long axis when the prosthesis is implanted within a scleral pocket or tunnel. The other end of the central body portion may have a blunted end portion including grooves for receiving a edge or lip of an incision forming the scleral tunnel to inhibit the prosthesis from sliding within the scleral tunnel. Curvature of the bottom surface of the central body portion may be greater than the curvature of the innermost surface of the scleral tunnel so that contact between the scleral and the bottom surface of the prosthesis is primarily with the end portions.