Replacement of human sight-is it possible

Pioneering work by G.S. Brindley and W.S. Lewin (1968), and W.H. Dobelle (1974) laid the foundation of technical feasible visual prosthesis. The technique is simple in concept, and image is divided into an array of small elements or pixels. The number of pixels is reduced to the number of phosphenes made available by implantation of an array of electrodes on the surface of the visual cortex. The position of these phosphenes have been previously mapped in the visual field. There are, however, a number of problems to surmount; the minimum number of electrodes required for a useable image, implant power, implant packaging and the construction of the electrodes. The present author addresses these problems and describes the prostheses being designed and constructed at the Midland Centre for Neurosurgery