At present, effective treatments are not available for patients who have a complete loss of the photoreceptor cells such as patients with retinitis pigmentosa. An artificial retina is a device to restore vision by stimulating the residual retinal neurons with electrical currents. After placing the multi-channel electrode adjacent to the retina, the retina is stimulated by the processed signals. Patients may perceive an image such as those presented on the retina. An artificial retina is an artificial organ in the visual system and is expected to become clinically available in the near future sooner than treatments by the regeneration of photoreceptors. Requirement of candidates for artificial retina No abnormality in visual pathway posterior to retinal ganglion cells. Targeted diseases Retinitis Pigmentosa Autoimmune Retinopathy Age-related macular degeneration