Gene therapy: New hopes to halt blindness
28 October 2011 Last updated at 09:11 BST
Researchers in Oxford are developing a genetic therapy which they hope could eventually stop people going blind.
They have treated Jonathan Wyatt who is in his 60s and on the verge of losing his sight.
As Pallab Ghosh reports, if the new technique works, the gene therapy could transform the lives of thousands of people in years to come.