Contributed Session III: Characteristics of electrically-induced visual percepts in the first human with the Intracortical Visual Prosthesis

Abstract

The Intracortical Visual Prosthesis (ICVP) consists of multiple wireless floating microelectrode arrays (WFMAs), each with 16 stimulating electrodes. Stimulation of these electrodes can potentially provide artificial vision for people who are blind. Twenty-five WFMAs were implanted in the right occipital visual cortex of a participant in an FDA-approved, NIH-sponsored Phase 1 clinical trial (NCT04634383). Here, we report characteristics of visual percepts elicited by the WFMAs (frequency: 200 Hz, cathodic phase duration: 200 µs, amplitude and train length up to 60 µA and 900 ms). Stimulation of single electrodes in 10 WFMAs and groups of 4 or more electrodes in 7 additional WFMAs consistently produced percepts during >10 sessions across approximately 3 months of testing. Phosphenes generated within a single WFMA were typically similar in appearance. Descriptions included configurations of rings, bright or dark dots, and constant or flickering bars, with sizes of 0.3–12° across. Phosphenes appeared as blueish-white, or occasionally orange, red, or having an iridescent texture. Ten WFMAs produced phosphenes within a 4° cluster centered 4° below and to the left of fixation. Phosphenes from 4 other WFMAs were located 4° below or 20° left of the cluster. When using these phosphenes to scan a virtual line, the participant was able to discriminate horizontal and vertical lines (46/51 correct, p < 10^−8, binomial test), and 45° and 135° diagonal lines (12/14 correct, p < 0.01).