Toward a high visual-acuity retinal prosthesis

We report retinal prosthesis devices with specifications needed to support a high visual acuity (VA) up to 20/168 and a large field of view (FOV). These devices use a flexible CMOS image sensor technology to integrate an array of “pixels”, each comprises of an electrode, photo sensor, signal processor and driver, into a single chip in a biocompatible and flexible format, and the total thickness including passivation layers is ~30 μm; these devices, having 4,096~16,384 pixels 30 μm in pitch, can be formed into a contact-lens-shaped surface conforming to the retina and minimizes the neuron-to-electrode distance needed to increase the resolution while decreasing the threshold power per pixel. We also integrated a selectable Laplacian-of-Gaussian circuit to imitate the lateral inhibition by horizontal cells to cone cells and the center-surround feature for subretinal implants.