Feasibility of Stimulating the Visual Cortex in Blind

In this study, the investigators intend to evaluate the use of a commercially available neurostimulator system, NeuroPace RNS System to stimulate the visual cortex. The NeuroPace RNS System has a proven record of safety and reliability was approved by the FDA in November 2013. The RNS System is indicated for use in patients with epilepsy and includes a skull implanted neurostimulator. No modification to the RNS System is required for this study. This study will use this device to better understand the effect of stimulation on the visual parts of the brain. The main purposes of this study are to confirm the desired location to implant a device in the visual cortex, determine the amount of energy needed to elicit vision, and assess the nature of the vision that is produced. This information is important to have early in the process of designing a visual cortical prosthesis that could eventually be used for commercial use.