Restoring sight to the visually impaired poses significant challenges across multiple disciplines. In this demonstration, we present a prototype vision processing system to perform the external processing and to provide a technical user interface for a vision prosthesis. The system transforms an input video stream into intensity values suitable for transmission to a stimulation array implanted within the retina of an impaired eye. This FPGA prototype ensures the processing is fast, accurate, and has low power consumption. We demonstrate our progress to date and hope thereby to stimulate interest in this emerging and challenging application area.