Share Email Print
cover

Proceedings Paper

Photovoltaic restoration of sight with high visual acuity in rats with retinal degeneration
Author(s): D. Palanker; Georges Goetz; H. Lorach; Yossi Mandel; Richard Smith; David Boinagrov; Xin Lei; Theodore I. Kamins; J. Harris; K. Mathieson; A. Sher
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Patients with retinal degeneration lose sight due to gradual demise of photoreceptors. Electrical stimulation of the surviving retinal neurons provides an alternative route for delivery of visual information. Subretinal photovoltaic arrays with 70μm pixels were used to convert pulsed near-IR light (880-915nm) into pulsed current to stimulate the nearby inner retinal neurons. Network-mediated responses of the retinal ganglion cells (RGCs) could be modulated by pulse width (1-20ms) and peak irradiance (0.5-10 mW/mm2). Similarly to normal vision, retinal response to prosthetic stimulation exhibited flicker fusion at high frequencies, adaptation to static images, and non-linear spatial summation. Spatial resolution was assessed in-vitro and in-vivo using alternating gratings with variable stripe width, projected with rapidly pulsed illumination (20-40Hz). In-vitro, average size of the electrical receptive fields in normal retina was 248±59μm – similar to their visible light RF size: 249±44μm. RGCs responded to grating stripes down to 67μm using photovoltaic stimulation in degenerate rat retina, and 28μm with visible light in normal retina. In-vivo, visual acuity in normally-sighted controls was 29±5μm/stripe, vs. 63±4μm/stripe in rats with subretinal photovoltaic arrays, corresponding to 20/250 acuity in human eye. With the enhanced acuity provided by eye movements and perceptual learning in human patients, visual acuity might exceed the 20/200 threshold of legal blindness. Ease of implantation and tiling of these wireless arrays to cover a large visual field, combined with their high resolution opens the door to highly functional restoration of sight.

Paper Details

Date Published: 20 March 2015
PDF: 5 pages
Proc. SPIE 9307, Ophthalmic Technologies XXV, 93070T (20 March 2015); doi: 10.1117/12.2081068
Show Author Affiliations
D. Palanker, Stanford Univ. (United States)
Georges Goetz, Stanford Univ. (United States)
H. Lorach, Stanford Univ. (United States)
Yossi Mandel, Bar-Ilan Univ. (Israel)
Richard Smith, Univ. of California, Santa Cruz (United States)
David Boinagrov, Stanford Univ. (United States)
Xin Lei, Stanford Univ. (United States)
Theodore I. Kamins, Stanford Univ. (United States)
J. Harris, Stanford Univ. (United States)
K. Mathieson, Univ. of Strathclyde (United Kingdom)
A. Sher, Univ. of California, Santa Cruz (United States)


Published in SPIE Proceedings Vol. 9307:
Ophthalmic Technologies XXV
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

© SPIE. Terms of Use
Back to Top