Estimation of phosphene spatial variability for visual prosthesis applications.
Visual prostheses are the focus of intensive research efforts to restore some measure of useful vision to blind or near-blind patients. The development of such technology is being guided to an extent by tools that simulate prosthesis behavior for healthy sighted subjects in order to assess system requirements and configurations. These simulators, however, typically assume purely deterministic phosphene properties and thus do not apply any variability to phosphene size, intensity, or location. We address this issue by presenting data on phosphene variability measured in a blind human subject fitted with an optic nerve prosthesis. In order to correct for normal limitations in human-pointing accuracy, the experimental conditions were repeated with sighted subjects. We conclude that identical optic nerve stimulations can result in phosphenes whose perceived locations vary by up to 5 degrees of deviation angle and 10 degrees of position angle. The consistency of phosphenes presented in the peripheral field of view can vary by an additional 3 degrees.
Obeid
Iyad
I
Department of Electrical and Computer Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122, USA. iobeid@temple.edu
Veraart
Claude
C
Delbeke
Jean
J
D000328:Adult; D001766:Blindness / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000601:surgery*; D010719:Phosphenes; D019736:Prostheses and Implants; D055815:Young Adult