Subretinal Implant Surgery in a Series of 26 Cat Eyes to Prove Evidence of Cortical Activation

Abstract

Abstract: : Purpose: To judge the resolution of subretinal prosthesis and to proof the feasibility of the concept microphothodiode arrays (MPDA) and foil bound stimulation electrodes were implanted in the subretinal space of cats. Different surgical approaches for the cat model were developed and tested to obtain the required information. Methods: MPDA´s were implanted in 16 cat eyes to demonstrate the safety of the procedure and to obtain electrophysiological and neurophysiological data in chronic implants. 10 eyes received foil bound stimulation arrays 7 of them were acute trials. One of the ten was a chronic implant which had a transscleral connection to the subretinal space. Two foil bound implants were placed completely in the subretinal space (active implants with the possibility to supply additional energy). All implants were placed using different model adapted variations of vitrectomy. Results: All 16 MPDA´s were successfully implanted in the subretinal space and showed stable retinal conditions in long term follow up (up to 1 year). Modifications of the MPDA minimized surgical trauma. Foil bound stimulation arrays with extraocular connections were successfully implanted in acute and chronic trials and electrophysiological and neurophysiological data could be obtained. Complex foil bound subretinal devices (active implants) were successfully implanted in cat. Conclusions: The different surgical strategies opened the way to collect the required basic data in an appropriate model concerning electrophysiology and neurophysiology. Safe implantation strategies and transferable data can be obtained. CR: None Support BMBF Retina Implant

Keywords: 554 retina • 316 animal model • 621 visual cortex