A retinal prosthesis, developed at the Duke Eye Center in North Carolina, allowed Larry Hester to see for the first time in 33 years after being diagnosed with retinitis pigmentosa, a disease that causes deterioration of the retina. The retina is a thin layer of photosensitive tissue in the back of the eye that triggers neural impulses that form images in the brain. This prosthesis partially compensates for the damaged retinal cells, returning Hester’s vision. His new-found sight isn’t perfect; he can’t clearly see objects, but he can visualize dots of light and distinguish light from dark.
Image source: Callista Images
The prosthesis is comprised of three components: a video camera mounted on a pair of glasses, a video processing unit carried by the patient, and an electric stimulator that is implanted in the eye. The camera takes videos, sends it to the video processing unit to be processed into electric signals, and then wirelessly transmits the processed signals to undamaged retinal cells via the electric stimulator. The brain interprets these signals as bits of bright and dark patches that translate into various objects like doors, walls, and street signs.
While this device can’t restore normal eyesight, it can act as a visual guide for patients, allowing them to more easily navigate their environment.
Feature Image Source: Vision by Ajit Patil
