Chronically implantable retinal prosthesis

Abstract

A combination of silicon processing technology advances and increased understanding of the mechanisms underlying phosphene generation in human retinas by surface electrical stimulation has now made it possible to conceive of a chronically implantable retinal prosthesis for the blind which will restore some useful vision to patients over at least several degrees of their former field of view. These thin, strong, and flexible epiretinal devices are constructed of or encapsulated in known biocompatible materials which will have a long working life in the eye's saline environment. The function of the implants is to electrically stimulate the ganglion cell layer at the surface of the retina using controlled current sources. Due to the exceptionally low mass of the implant and its flexible, nearly planar form, patient discomfort and fluid drag caused by the implant minimized. These physical atttributes also substantially reduce the potential of harm to the most delicate structure of the eye, the retina, and therefore enhance the long term safety and biocompatibility of the device. Since no micro-cables are required to be attached to the device, and its overall form and edges are rounded, the device is not expected to stress the retina during chronic implantation. A provision is also made for nutrients to reach the retinal cells underneath the device to assure their long-term health.

Dependencies are inferred from the claim text.