April 27, 2006

A new solar-powered chip that stimulates retinal cells by spraying them with neurotransmitters may help restore eyesight. Engineer Laxman Saggere at the University of Illinois in Chicago has built a solar-powered actuator that flexes in response to the very low-intensity light that strikes the retina. The new component enhances an implant he unveiled last year.

While other retinal implants under development apply an electric charge directly to retinal cells, the new device does heat those cells. It also uses very little power, so it does not need external batteries.

The retina lines the back and sides of the eyeball. It contains neurtransmitters -- cells that release signalling chemicals in response to light. The neurotransmitters pass into nerve cells on top of photoreceptor cells that relay signals to the brain through a series of electrical and chemical reactions.