An optically powered single-channel stimulation implant as test system for chronic biocompatibility and biostability of miniaturized retinal vision prostheses.

A microsystem based microimplant with an optically powered single-channel stimulator was designed and developed as test system for an epi-retinal vision implant. Biostability of the hybrid assembly and the encapsulation materials were evaluated in pilot experiments in chronic implantations in a cat animal model. The implant was fabricated on a flexible polyimide substrate with integrated platinum electrode, interconnection lines, and contact pads for hybrid integration of electronic components.

Towards the cortical representation of form and motion stimuli generated by a retina implant.

Background: A retina implant for restoring basic visual perception in patients who are blind due to photoreceptor loss should not only evoke focal phosphenes at high resolution, but should also generate cortical representations of form and motion. We are currently exploring these potential capabilities in anaesthetised cats.

Methods: Fibre electrodes were inserted through a small scleral incision onto the retinal surface for stimulation.