Thomas M O'Hearn | PubMed Health

PubMed2006

Electrical stimulation in normal and retinal degeneration (rd1) isolated mouse retina.

Stimulus threshold and response latencies were measured for electrically elicited retinal ganglion cell responses in retina isolated from the eyes of normal and retinal degenerate (rd1) mice. Stimulation of the ganglion cell-side in normal retina yielded a significantly lower mean threshold and shorter latency when compared with stimulation of the photoreceptor side in normal retina. The latency of the ganglion cell-side stimulation in normal retina also proved to be significantly shorter than the latency for stimulation of the ganglion cell side in rd1 retina. Thus both the electrode positioning as well as the health of the retinal tissue play a role in the stimulating current required to elicit a retinal response.

Animals↗

PubMedDate not supplied

Retinal prosthesis for the blind.

Most of current concepts for a visual prosthesis are based on neuronal electrical stimulation at different locations along the visual pathways within the central nervous system. The different designs of visual prostheses are named according to their locations (i.e., cortical, optic nerve, subretinal, and epiretinal). Visual loss caused by outer retinal degeneration in diseases such as retinitis pigmentosa or age-related macular degeneration can be reversed by electrical stimulation of the retina or the optic nerve (retinal or optic nerve prostheses, respectively). On the other hand, visual loss caused by inner or whole thickness retinal diseases, eye loss, optic nerve diseases (tumors, ischemia, inflammatory processes etc.), or diseases of the central nervous system (not including diseases of the primary and secondary visual cortices) can be reversed by a cortical visual prosthesis. The intent of this article is to provide an overview of current and future concepts of retinal and optic nerve prostheses. This article will begin with general considerations that are related to all or most of visual prostheses and then concentrate on the retinal and optic nerve designs. The authors believe that the field has grown beyond the scope of a single article so cortical prostheses will be described only because of their direct effect on the concept and technical development of the other prostheses, and this will be done in a more general and historic perspective.

Blindness↗