Retinal Prosthesis Phosphene Perception

An epiretinal implant restores rudimentary vision by driving current through an electrode array resting on the retina, exciting nearby ganglion cells and producing a perceived spot of light — a phosphene. This simulator renders the electrode array and the current-spread field it generates on one side, and the resulting phosphene in the patient's perceived visual field on the other, driven by the same three parameters clinicians actually tune: stimulus current amplitude, which electrode is active (its distance from the fovea), and pulse frequency. Current amplitude sets how much retinal tissue is activated via a threshold current-spread relation; the retina's eccentricity-dependent magnification factor then converts that physical activation into a phosphene of a specific angular size, exactly as clinical reports describe peripheral electrodes producing larger, less punctate phosphenes than foveal ones; pulse frequency separately drives a saturating brightness response. Live readouts track the activated-tissue radius, the phosphene's visual angle, and its perceived brightness as you adjust each control.