Most causes of untreatable blindness occur due to loss of the millions of light sensitive photoreceptor cells that line the retina, similar to the pixels in a digital camera.
The remaining retinal nerve cells which are not light sensitive, however, remain in the eye.
The study, published in the journal Proceedings of the National Academy, used a viral vector to express a light sensitive protein, melanopsin, in the residual retinal cells in mice which were blind from retinitis pigmentosa, the most common cause of blindness in young people.
The cells expressing melanopsin were able to respond to light and send visual signals to the brain, they 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 Samantha de Silva, from University of Oxford.
"Our next step will be to start a clinical trial to assess this in patients," de Silva added.