Methods for improving damaged retinal cell function

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS In the course of testing for the safety and efficacy of retinal implants in humans blinded by retinitis pigmentosa, an unexpected and surprising observation was made: even though the implants were placed at a discrete location in the subretinal space (acting as a prosthesis), vision was improved not only in those discrete locations as expected, but also in distant locations of the retina.
Thus chronic electrical stimulation in specific locations enhanced retinal cell function throughout the eye.
This "halo effect" can be used to improve vision in those individuals who suffer from diseases, conditions and traumas that have damaged the outer retinal layer but leave the inner retinal layer at least partially intact.
Although prosthetic electrical devices designed to replace damaged or missing retinal cells have been used to treat vision loss caused by outer retinal degeneration, electrical stimulation to improve large areas of retinal cell visual function is novel.
As a non-limiting explanation, the promotion of improved retinal cell visual function by chronic electrical stimulation may be explained by the stimulation of production and release of growth factors; more specifically, neurotrophic-type growth factors, by the stimulated retinas.
The synthesis and/or secretion of neurotrophic factors would then improve retinal cell function and survival in conditions where these activities would be lost.
The present invention discloses both devices and novel methods to electrically stimulate the retina to improve large areas of retinal visual function and to protect the retina from degeneration.
Definitions Subject/patient A subject (patient) may be a human being or a non-human animal, but is preferably a human.
Usually the individual has suffered some type of retinal damage and/or degeneration that results in some degree of visual loss and/or has a condition that will result in retinal damage and/or degeneration.
A normal (healthy) subject does not have a condition that will result in retinal damage and/or degeneration and/or has not suffered retinal damage and/or degeneration