Clinical Outcomes Argus® II Clinical Trial The Argus II Study Group includes 11 centers located throughout Europe, the United States and Mexico. A two-patient pilot study was initiated in Mexico in 2006, followed by a 30-patient trial in Europe and the United States. As of December, 2015, over 200 patient-years experience has been gathered overall. This is the most clinical experience of any retinal prosthesis ever developed. Additional information is available upon request here HUMANITARIAN DEVICE: Authorized by Federal (U.S.) law to provide electrical stimulation of the retina to induce visual perception in blind patients with severe to profound retinitis pigmentosa and bare light or no light perception in both eyes. The effectiveness of this device for this use has not been demonstrated.