Electronic “photoreceptors” enable prosthetic vision with acuity matching the natural resolution in rats

Localized stimulation of the inner retinal neurons for high-acuity prosthetic vision requires small pixels and minimal cross-talk from neighboring electrodes. Local return electrodes within each pixel limit crosstalk, but can over-constrain the electric field, thus precluding efficient stimulation with subretinal pixels smaller than 50 μm. Here we demonstrate high-resolution prosthetic vision based on a novel design of a photovoltaic array, where field confinement is achieved dynamically, leveraging the adjustable conductivity of the diodes under forward bias to turn the designated pixels into transient returns. We validated computational modeling of the field confinement in such an optically-controlled circuit by ex-vivo and in-vivo measurements. Most importantly, using this strategy, we demonstrated that the grating acuity with 40 μm pixels matches the pixel pitch, while with 20 μm pixels, it reaches the 28 μm limit of the natural visual resolution in rats. This method enables customized field shaping based on individual retinal thickness and distance from the implant, paving the way to prosthetic vision with acuity as high as 20/80 in atrophic macular degeneration. ### Competing Interest Statement D. P. and T. K. serve as consultants to Pixium Vision. D. P.'s patents related to retinal prostheses are owned by Stanford University and licensed to Pixium Vision. All other authors declare no financial interests.