title: Cortical responses elicited by photovoltaic subretinal prostheses exhibit similarities to visually evoked potentials.
abstract: We have previously developed a wireless photovoltaic retinal prosthesis, in which camera-captured images are projected onto the retina using pulsed near-IR light. Each pixel in the subretinal implant directly converts pulsed light into local electric current to stimulate the nearby inner retinal neurons. Here we report that implants having pixel sizes of 280, 140 and 70 μm implanted in the subretinal space in rats with normal and degenerate retina elicit robust cortical responses upon stimulation with pulsed near-IR light. Implant-induced eVEP has shorter latency than visible light-induced VEP, its amplitude increases with peak irradiance and pulse duration, and decreases with frequency in the range of 2-20 Hz, similar to the visible light response. Modular design of the arrays allows scalability to a large number of pixels, and combined with the ease of implantation, offers a promising approach to restoration of sight in patients blinded by retinal degenerative diseases.
authors.affiliation: Hansen Experimental Physics Laboratory, Stanford University, Stanford, California 94305, USA. mandely@stanford.edu
authors.forename: Yossi
authors.initials: Y
authors.lastname: Mandel
authors.forename: Georges
authors.initials: G
authors.lastname: Goetz
authors.forename: Daniel
authors.initials: D
authors.lastname: Lavinsky
authors.forename: Philip
authors.initials: P
authors.lastname: Huie
authors.forename: Keith
authors.initials: K
authors.lastname: Mathieson
authors.forename: Lele
authors.initials: L
authors.lastname: Wang
authors.forename: Theodore
authors.initials: T
authors.lastname: Kamins
authors.forename: Ludwig
authors.initials: L
authors.lastname: Galambos
authors.forename: Richard
authors.initials: R
authors.lastname: Manivanh
authors.forename: James
authors.initials: J
authors.lastname: Harris
authors.forename: Daniel
authors.initials: D
authors.lastname: Palanker
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D005074:Evoked Potentials, Visual / Q000502:physiology*; D010775:Photic Stimulation; D019919:Prosthesis Implantation; D051381:Rats; D012160:Retina / Q000502:physiology / Q000648:ultrastructure; D012162:Retinal Degeneration / Q000503:physiopathology; D019265:Spectroscopy, Near-Infrared; D034421:Sus scrofa; D014793:Visual Cortex / Q000503:physiopathology*; D057488:Visual Prosthesis