Image perception of vision impaired by epi-retinal electrode stimulation

This Retinal prostheses, which helps the vision impaired patients with outer retinal degeneration, uses an outside camera to detect image, convert light energy of the image into a pattern electrical stimulation signal which is transmitted to an array of electrodes placed on the retinal surface, stimulate the remaining retinal ganglion cells to elicit electric activity which is pass down to optic nerve for final processing in the brain and synthesis of a visual image. The visual pathway functions as a complex image processor as well as an information conduit. At higher levels, the visual signals arrive with significant processing completed. In reality due to its easier access, simpler processing and the retinotopic organization, the retina has been the primary focus for artificial stimulation. Studies suggest that retinal implants may provide the patients with an acceptable level of visual mobility via a typical implanted electrode array containing tens of electrodes. In this study, a wide field implantable epi-retinal microelectrode array was designed and fabricated with parylene as flexible substrate material and Pt as electrode and route material, feature test was carried out on the array, and electric characteristics of the array was tested. The feature analysis showed that morphological and electrical properties of the array well met the requirements of implantation and electrical stimulation of retina. The pattern stimulation protocols and projected visual field were discussed.