Neural stimulation for increased contrast
The present invention is a method of improving the contrast of electrical neural stimulation and expanding the dynamic range for brightness, and specifically a method of improving the contrast of an image supplied to the retina, or visual cortex, through a visual prosthesis. The background brightness for a blind subject is often not perfectly black, but a dark gray or brown. When stimulating visual neurons in the retina, low current stimulation tends to create a dark percept, the perception of a phosphene darker than the background brightness level perceived in the un-stimulated state. The human retina contains neurons that signal light increments (“on” cells) and neurons that signal light decrements (“off” cells). In a healthy retina, the on cells tend to fire in response to an increase in light above the background level, while the off cells tend to fire in response to a decrease in light below the background level.
Second Sight Medical Products, Inc.
A A
A61N A61N
additional inventional
Matthew J. Robert J.
McMahon Greenberg