Apparatus comprising: a visual prosthesis (1, 200) comprising: a substrate (10, 210) having a distal end (111, 211) and a proximal end (112,212); a plurality of electrodes (13, 213) located at or adjacent the distal end (111, 211) of the substrate, wherein the distal end (111, 211) of the substrate is configured for insertion, via an incision, to a stimulation position between first and second tissue layers (21, 22) of an eye, and a cable (42, 242) extending outwardly from the substrate (10, 210) and providing a means for electrically communicating with the electrodes (13, 213), the cable (42, 242) being configured to extend through the incision when the distal end (111, 211) of the substrate is in the stimulation position; and an anchor (45, 245) connected to the cable (42, 242), the apparatus being characterized in that: the anchor (45, 245) is configured to extend over the cable (42, 242) and over the incision at the outer surface of the eye and attach to the outer surface of the eye when the substrate (10, 210) is in the stimulation position; and the anchor is in the form of a patch (45, 245). a visual prosthesis (1, 200) comprising: a substrate (10, 210) having a distal end (111, 211) and a proximal end (112,212); a plurality of electrodes (13, 213) located at or adjacent the distal end (111, 211) of the substrate, wherein the distal end (111, 211) of the substrate is configured for insertion, via an incision, to a stimulation position between first and second tissue layers (21, 22) of an eye, and a cable (42, 242) extending outwardly from the substrate (10, 210) and providing a means for electrically communicating with the electrodes (13, 213), the cable (42, 242) being configured to extend through the incision when the distal end (111, 211) of the substrate is in the stimulation position; and an anchor (45, 245) connected to the cable (42, 242), the apparatus being characterized in that: the anchor (45, 245) is configured to extend over the cable (42, 242) and over the incision at the outer surface of the eye and attach to the outer surface of the eye when the substrate (10, 210) is in the stimulation position; and the anchor is in the form of a patch (45, 245). a substrate (10, 210) having a distal end (111, 211) and a proximal end (112,212); a plurality of electrodes (13, 213) located at or adjacent the distal end (111, 211) of the substrate, wherein the distal end (111, 211) of the substrate is configured for insertion, via an incision, to a stimulation position between first and second tissue layers (21, 22) of an eye, and a cable (42, 242) extending outwardly from the substrate (10, 210) and providing a means for electrically communicating with the electrodes (13, 213), the cable (42, 242) being configured to extend through the incision when the distal end (111, 211) of the substrate is in the stimulation position; and an anchor (45, 245) connected to the cable (42, 242), the apparatus being characterized in that: the anchor (45, 245) is configured to extend over the cable (42, 242) and over the incision at the outer surface of the eye and attach to the outer surface of the eye when the substrate (10, 210) is in the stimulation position; and the anchor is in the form of a patch (45, 245). the anchor (45, 245) is configured to extend over the cable (42, 242) and over the incision at the outer surface of the eye and attach to the outer surface of the eye when the substrate (10, 210) is in the stimulation position; and the anchor is in the form of a patch (45, 245).