Retinal implants are in the early stages of development and their use could be of benefit to many people with Visual impairment though implanting and maintaining an electrical device within the eye that interfaces with the optic nerve presents many challenges. An example of a device is made by Argus retinal prosthesis, the camera is an external device held on spectacles, the camera signal is processed and then fed via wires into the retina to terminate in some electrodes that interface with the optic nerve.