Predicting Visual Sensitivity in Retinal Prosthesis Patients

PURPOSE. With the long-term goal of restoring functional vision in patients with retinal degenerative diseases, the eyes of blind human subjects were implanted chronically with epiretinal prostheses consisting of two-dimensional electrode arrays that directly stimulated cells of the neural retina. METHODS. Psychophysical techniques were used to measure the brightness of electrically generated percepts on single electrodes using a variety of electrical stimulation patterns. RESULTS. It was possible to predict the sensitivity of the human visual system to a wide variety of retinal electrical stimulation patterns using a simple and biologically plausible model. CONCLUSIONS. This is the first study to demonstrate that, on the single-electrode level, retinal electrical stimulation in humans can produce visual qualia that are predictable using a quantitative model, a prerequisite for a successful retinal prosthesis. (ClinicalTrials.gov number, NCT00279500.) (Invest Ophthalmol Vis Sci. 2009; 50: 1483-1491) DOI:10.1167/iovs.08-2595