Researchers have shown that gene therapy might help reverse blindness by reprogramming cells at the back of the eye to become light sensitive.

Retinitis pigmentosa -- the most common cause of blindness in young people -- occurs mostly due to loss of millions of light sensitive photoreceptor cells that line the retina.The remaining retinal nerve cells, which are not light sensitive, however, remain in the eye which can be treated using gene therapy, the researchers said."There are many blind patients in our clinics and the ability to give them some sight back with a relatively simple genetic procedure is very exciting," said lead author Samantha de Silva, specialist registrar, Ophthalmology and Clinical research training fellow at the University of Oxford. 

"Our next step will be to start a clinical trial to assess this in patients."In the study, detailed in the Proceedings of the National Academy of Sciences, the team used a viral vector to express a light sensitive protein, melanopsin, in the residual retinal cells in mice which were blind from retinitis pigmentosa.Post treatment, the mice were monitored for over a year and they maintained vision during this time as they were able to recognise objects in their environment which indicated a high level of visual perception. The cells expressing melanopsin were able to respond to light and send visual signals to the brain, the researchers said.