The retina at the back of the eye contains light detecting cells called photoreceptors. These cells convert light energy into electrical energy, which is transmitted to the brain via several layers of retinal nerve cells. In several forms of blindness, such as age related macular degeneration and retinitis pigmentosa, the photoreceptors die but leave the other nerve cells in tact. While those nerve cells cannot detect light themselves, they can respond to electrical stimulation.
A bionic eye can bypass the visual display and send the electrical signals from each pixel in a camera to an array of stimulating electrodes positioned on the eye. This sends information to the brain, which in turn experiences a pattern of electrical signals that replicates those experienced via the normally functioning eye. The NVRI is focused on better understanding the connections and developing an electrode array that will ensure a device that can provide the best results possible.