Contribution to the Theory of Prosthetic Vision

By way of extracellular, electrical stimulation of the visual pathway, the various approaches to vision prosthesis aim to provide crude, patterned vision to individuals with profound blindness. Common to all approaches is the implantable electrode array and the rendering of phosphenes-the actuated percepts occupying the visual field of the implantee. Thus prosthetic vision may be simulated, and underlying theories as to how to render it efficacious developed. We review the field of simulated prosthetic vision. Furthermore, with retinal prosthesis in mind, we suggest a revised approach-an approach with regard to sampling theory, the vertebrate central visual pathway, and eye movements. The parallel development of prosthetic vision theory, explored via simulation and bioengineering issues surrounding neurostimulator design and implantation has bearing on the success of clinical trials by numerous groups in coming years.