Abstract: The present disclosure relates to visual prosthesis apparatus including an implantable device having a substrate and a plurality of electrodes located in or on the substrate, the substrate adapted to be implanted at least partially in an eye of a patient. A first inductor is included in the implantable device, for example by encapsulating an inductor coil in the substrate or on an associated lead or anchor device. In some instances, the electrodes in the substrate may partially provide the first inductor. A second inductor is adapted to locate externally to the eye and inductively couple with the first inductor. A processor is adapted to determine a direction of movement of the eye based on changes in electrical current induced in one of the first and second inductors due to relative movement of the first and second inductors.