Functionality and Performance of the Subretinal Implant Chip Alpha AMS

Electronic retinal implants have been developed and are marketed as a therapeutic option for blind people suffering from degenerative retinal diseases such as retinitis pigmentosa. The functionality of subretinal implants depends heavily on the performance of the electronic interface to the retina. For the RETINA IMPLANT Alpha AMS device, this interface consists of a subretinally implanted chip that samples the retinal image, like a camera chip, and stimulates the adjacent retina simultaneously at the corresponding locations. The technical functionality of the RETINA IMPLANT Alpha AMS is described and compared with the outcome of two clinical trials over an observation period of one year. The discrimination of different grey levels observed in these clinical trials confirms that the sensitivity of the implanted CMOS chip can be varied over the range of relevant light intensities. We show that accelerated aging lifetime measurements of implant components in a laboratory environment match implant lifetimes observed during clinical trials for the predecessor device, the RETINA IMPLANT Alpha IMS. By using the same model for the current technically advanced device, the RETINA IMPLANT Alpha AMS, the predicted clinical lifetime of the implant is about 5 years.