Position, size and luminosity of phosphenes generated by direct optic nerve stimulation.

Abstract

Pulses of low intensity current, delivered through a cuff electrode chronically implanted around the optic nerve of a blind retinitis pigmentosa patient generate visual sensations. These phosphenes are obtained at lower thresholds for a train of stimuli than for single pulses, which suggests the existence of a spatial and temporal integrating mechanism. The perceptions are much smaller than those predicted from model simulations. A set of equations are derived which show the effect of pulse current, duration, number and frequency on the position, size and, to some extent, luminosity of the resulting phosphenes.

• Authors: Jean Delbeke, Medhy Oozeer, Claude Veraart
• Journal: Vision research (Vision Res) Vol. 43 Issue 9 Pg. 1091-102 (Apr 2003) ISSN: 0042-6989 [Print] England
• PMID: 12676250 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Adult
• Blindness (etiology, physiopathology, therapy)
• Electric Stimulation
• Electrodes, Implanted
• Female
• Humans
• Optic Nerve (physiopathology)
• Phosphenes
• Prosthesis Implantation
• Psychophysics
• Retinitis Pigmentosa (complications, physiopathology, therapy)
• Sensory Thresholds