Switching eyesight back on

A new research centre at the

and

(LBNL) aims to put light-sensitive switches in the body's cells. Optical switches like these could trigger a chemical reaction, initiate a muscle contraction, activate a drug or stimulate a nerve cell triggered by a flash of light.

One major goal of the UC Berkeley-LBNL Nanomedicine Development Centre is to equip cells of the retina with photoswitches, essentially making blind nerve cells see, restoring light sensitivity in people with degenerative blindness such as macular degeneration.

It involves altering an ion channel commonly found in nerve cells so that the channel turns the cell on when zapped by green light and turns the cell off when hit by ultraviolet light.

The researchers demonstrated in 2004 that they could turn cultured nerve cells on and off with this optical switch. Since then, they've injected photoswitches into the eyes of rats that have a disease that kills their rods and cones, and have restored some light sensitivity to the remaining retinal cells.

The next step is to develop viruses that can carry the photoswitches into the correct cells, new types of photoswitches based on other chemical structures, and strategies for achieving the desired control of cell processes.

The research will focus on restoring the response to light in the eyes of people who have lost their photoreceptor cells, in particular, the rods and cones in the most sensitive part of the retina. The plan is to develop the tools to create a new layer of optically active cells for the retina.