118(11):2227-2237 November 2011
Degenerative diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP) primarily affect the photoreceptors, ultimately resulting in significant loss of vision. Retinal prostheses aim to elicit neural activity in the remaining retinal cells by detecting and converting light into electrical stimuli that can then be delivered to the retina. The concept of visual prostheses has existed for more than 50 years and recent progress shows promise, yet much remains to be understood about how the visual system will respond to artificial input after years of blindness that necessitate this type of prosthesis. This review focuses on 3 major areas: the histopathologic features of human retina affected by AMD and RP, current results from clinical trials, and challenges to overcome for continued improvement of retinal prostheses.