Observational Study of the Argus® II Retinal Prosthesis System

Inclusion Criteria: •Adults, age 25 years or older with severe to profound outer retinal degeneration. but some residual light perception. If no residual light perception remains, the retina must be able to respond to electrical stimulation and previous history of useful form vision. Exclusion Criteria: * Ocular diseases or conditions that could prevent the Argus II System from working (e.g. optic nerve disease, central retinal artery or vein occlusion, history of retinal detachment, trauma, severe strabismus). * Ocular structures or conditions that could prevent the successful implantation of the Argus II Implant or adequate healing from surgery (e.g. extremely thin conjunctiva, axial length \<20.5 mm or \> 26 mm, corneal ulcers, choroidal neovascularisation in the area of the intended tack location, etc.). * Ocular diseases or conditions (other than cataracts) that prevent adequate visualisation of the inner structures of the eye (e.g. corneal opacity, etc.). * Inability to tolerate general anaesthesia or the recommended antibiotic and steroid regimen associated with the implantation surgery. * Predisposition to eye rubbing.