Retinal prostheses are implantable electronic devices designed to stimulate the sensation of vision in the eyes of individuals with significant retinal diseases such as retinitis pigmentosa or age-related macular degeneration, with no damage to the optic nerve or visual cortex.
We in Choroida are extremely interested in this type of prosthesis as it provides help to patients with impaired vision.
In the normal eye, photoreceptors within the retina’s outer layers contain a light-sensitive pigment that triggers the phototransduction cascade to generate neuronal signals in the presence of light stimuli.
These signals are processed by a complex network of neurons within the middle layers of the retina before reaching the retinal ganglion cells.
By gradually destroying the outer layers of the retina, congenital retinal dystrophy, such as retinitis pigmentosa, causes progressive loss of vision.
However,,
restore vision by creating devices
inner retinal layers including RGCs are partially spared. It is possible to restore vision by creating devices, retinal prostheses, that receive and process incoming light before transmitting it as electrical impulses to the remaining inner retinal layers.
Although visual prostheses may conceivably be developed for any part of the visual pathway including the visual cortex itself, the retina is considered to be the easiest target for treating outer retinal disease due to its easy access and partially intact geospatial neuronal architecture and processing units.
Generally, devices are placed epiretinal, adjacent to the retinal pigmented epithelium and photoreceptor layers, or subretinally, outside of the retina adjacent to or in place of those structures.
Epiretinal designs benefit from being easier and less risky to the implant. Amacrine, horizontal, and bipolar cells form middle retinal layer processing pathways for subretinal designs.
Alternatively, devices may be placed outside the sclera or between the choroid and sclera.
RETINAL IMAGING BY YOUR SMARTPHONE
