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Proceedings Paper

Progress toward a high-resolution retinal prosthesis
Author(s): Alex Butterwick; Alex Vankov; Phil Huie; Karthik Vijayraghavan; Jim Loudin; Daniel Palanker
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Paper Abstract

Electronic retinal prostheses represent a potentially effective approach for restoring some degree of sight in blind patients with retinal degeneration. Functional restoration of sight would require hundreds to thousands of electrodes effectively stimulating remaining neurons in the retina. We present a design of an optoelectronic retinal prosthetic system having 3mm diameter retinal implant with pixel sizes down to 25 micrometers, which allows for natural eye scanning for observing a large field of view, as well as spatial and temporal processing of the visual scene to optimize the patient experience. Information from a head mounted video camera is processed in a portable computer and delivered to the implanted photodiode array by projection from the LCD goggles using pulsed IR (810 nm) light. Each photodiode converts pulsed light (0.5 ms in duration) into electric current with efficiency of 0.3 A/W using common bi-phasic power line. Power is provided by the inductively-coupled RF link from the coil on the goggles into a miniature power supply implanted between the sclera and the conjuctiva, and connected to subretinal implant with a thin 2-wire trans-scleral cable. 3-dimensional structures in the subretinal prosthesis induce retinal migration and thus ensure close proximity between stimulating electrodes and the target retinal neurons. Subretinal implantations of the 3-dimentional pillar and chamber arrays in RCS rats with 2 and 6 week follow-up demonstrate achievement of intimate proximity between the stimulation cites and the inner nuclear layer. In some instances formation of a fibrotic seal has been observed.

Paper Details

Date Published: 5 March 2007
PDF: 9 pages
Proc. SPIE 6426, Ophthalmic Technologies XVII, 64260R (5 March 2007); doi: 10.1117/12.701787
Show Author Affiliations
Alex Butterwick, Stanford Univ. (United States)
Alex Vankov, Stanford Univ. (United States)
Phil Huie, Stanford Univ. (United States)
Karthik Vijayraghavan, Stanford Univ. (United States)
Jim Loudin, Stanford Univ. (United States)
Daniel Palanker, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 6426:
Ophthalmic Technologies XVII
Bruce E. Stuck; Fabrice Manns; Per G. Söderberg; Michael Belkin M.D.; Arthur Ho, Editor(s)

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