Switching Eyes On

Deep in the back layer of our eyeballs, light triggers cells called photoreceptors – the long, rod-shaped cells stained green in this microscope image. Once activated, the photoreceptors send messages via nerve cells into the brain that enable us to see. Sometimes these photoreceptors break down and stop working properly, causing sight loss. But because the nerves wiring them to the brain are still intact, researchers are testing whether new genetic engineering techniques – known as optogenetics – can switch light-sensitivity back on and restore sight. Using a modified virus, they're adding a specially-designed light-activated protein molecule into cells at the back of the eye in blind mice. These molecular 'light switches' work amazingly well, turning on in response to light and bringing back the animals' vision. Although it's still early days, the exciting results bring hope that this technique could one day lead to new therapies for sight loss.

Written by Kat Arney

Kat Arney

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Dr Kat Arney is an award-winning science writer, broadcaster and public speaker, and is the founder and Creative Director of First Create The Media.

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• Image by Michiel van Wyk and colleagues
• University of Bern, Switzerland
• Originally published under a Creative Commons Licence (BY 4.0)
• Research published in PLOS Biology, May 2015