Perceptual Efficacy of Electrical Stimulation of Human Retina with a Microelectrode Array during Short-Term Surgical Trials

Abstract

Single percepts induced by single-electrode stimulation were relatively small, but the form of percepts, especially after multielectrode stimulation, often did not match the stimulation pattern, even in a normal-sighted volunteer. Reproducible percepts were more easily generated than those that matched the stimulation pattern.

Current and future prospects for optoelectronic retinal prostheses

“…Acute studies have been performed successfully with five patients with RP and one sighted patient. 25,26 A second German epiretinal prosthesis group, Epiret GmbH, has also recently successfully implanted a 25-electrode array (EPIRET3) into six patients over a 4-week period. 23 The implant was tolerated in five eyes with moderate post-operative inflammation, and the position of the implants remained stable until removal.…”

A Treatise of the Physical Aspects of Phosphenes and Single-Cell Selectivity in Retinal Stimulation

“…Phosphenes have been observed in the form of doughnut shapes [8], punctuate spots of light when occurring close to the center of the visual field [18,19], elongated shapes [22,25], lines/ bars [25,26], triangles [26], and more complicated patterns [26]. Phosphenes are commonly described as "round" spots of light [8-10, 15, 25, 27] and carrying some colors, such as red [26], blue [8,23,26], yellow [8,23,26], orange [8,18,26] and multicolor [26].…”

Redundant safety features in a high-channel-count retinal neurostimulator

“…The Retina Implant device uses 1500 non-configurable photodiode-electrode pixels, with wires delivering power to the chip. Our group performed short-term retinal stimulation trials on six blind volunteers between 1998 and 2000, showing that subjects can see individual spots and lines within an hour of electrode implantation [9]. But while these early clinical results provide a proof-of-concept for these types of devices, it is thought that larger numbers of independent channels are needed, which has spurred our group and others to develop higher-channel-count devices [6]- [8].…”