A FLEXIBLE RETINA IMPLANT FOR PEOPLE SUFFERING FROM RETINITIS PIGMENTOSA

Patients that are blind due to photoreceptor degeneration caused by retinitis pigmentosa or macula degeneration are able to perceive light sensations after localized electrical stimulation. This opens the possibility to restore vision by an artificial implant to some extend. Thirteen groups in the German EPI-RET consortium work on the development of an epiretinal implant for ganglion cell stimulation. Here, we present the development of flexible stimulation devices and the hybrid integration of all components to an implantable system. Micromachining technology has been used to realize 15 micron thin, ultra-light weighted and highly flexible substrates with 25 stimulation electrodes. Polyimide has been used as material for substrate and insulation layers. Gold and platinum or Iridium has been used for integrated conductive lines and electrodes, respectively. Cytotoxicity testing according to ISO and USP has been performed. The polyimide and the metals proved to be non toxic. An assembling technology has been developed to connect the microchips to the thin polyimide substrate. First prototypes exhibit excellent mechanical properties.