Describe some forms of blindness and the treatments being developed to restore sight in these individuals.

What will be an ideal response?

For the majority of individuals who are blind, the cause is a lack of or deficits in the photoreceptors. Since the main task of these photoreceptors is to convert light energy into an neural impulse, researchers have looked at ways to create devices that will do the job of the receptors. For instance, with the camera-based electrode grids, a tiny camera is mounted on a pair of glasses and converts images taken of the environment into a grid of electronic impulses delivered to the retina. Another strategy uses a light-sensitive chip that is placed behind the retina to convert images into an electronic signal.
Another area of research serves to find ways to allow the eye itself to gain/regain functioning on its own. For example, with the design of retinal prosthetics, photosensitive polymers are embedded just behind the retina, where they convert light to electrical signals. These signals are then picked up by the ganglion cells. In another method, a synthetic light-sensitive glutamate channel is inserted into ganglion cells to make them work like photoreceptors. Gene therapy also has promise where studies have observed restored vision in mice after a virus encoding a synthetic form of rhodopsin was injected or when a pigment gene was injected into the retina.