A bionic eye that allows the blind to see has been approved after thorough testing.

Tests have demonstrated that the device is safe, which could mean that it eventually becomes routinely available on the NHS. Specialists said that tests over almost three years had "impressed" beyond their "most optimistic expectations ," reports the Daily Express.

Revolutionary retina implants work in conjunction with a camera mounted on a pair of glasses. The camera sends signals to an implanted chip near the retina, which stimulates retinal cells and produces visual light patterns.

They have already transformed the lives of 30 people during initial tests. Doctors now hope the 'bionic eye' could be used to treat around 20,000 people in the UK who are blind because of failed retinas.

British eye surgeon Robert MacLaren , said it was a significant advance . "Until now this concept would have been considered only in the realms of science fiction," MacLaren , from the Oxford Eye Hospital , said. "What surprised all of us was just how much resolution you can get from the implant."