Visual prostheses—the past and the Future

We have entered a new era for visual prostheses brought about by the clinical application of this medical technology. Following the success of cochlear implants we are now starting to see patients fitted with retinal prostheses. Here I discuss the history of visual prosthesis development, the obstacles that have been faced along the path to its clinical use, some of the barriers that remain before its full promise can be fulfilled and ongoing research, which seeks to break down these barriers. The development of a complex medical device like a visual prosthesis can be considered a case study for the development of invasive medical devices, particularly those that interface with the nervous system. So the lessons learned in developing such devices should have value for those interested in developing other complex medical technologies. Vision is the sense that is most valued by humans and it occupies a substantial fraction of our brains. It is little surprising therefore that restoration of vision for those who have lost this sense is particularly valued.