Visual resolution with retinal implants estimated from recordings in cat visual cortex

We investigated cortical responses to electrical stimulation of the retina using epi- and sub-retinal electrodes of 20–100 μm diameter. Temporal and spatial resolutions were assessed by recordings from the visual cortex with arrays of microelectrodes and optical imaging. The estimated resolutions were ∼40 ms and ∼1° of visual angle. This temporal resolution of 25 frames per second and spatial resolution of about 0.8 cm at about 1 m and correspondingly 8 cm at 10 m distance seems sufficient for useful object recognition and visuo-motor behavior in many in- and out-door situations of daily life.