16:55 16 January 2014
Doctors at the Oxford Eye Hospital are celebrating following a gene therapy breakthrough that helps patients who are suffering from an inherited form of blindness improve their sight.
In the groundbreaking clinical trial, doctors injected a harmless virus that had been engineered to carry a working copy of a gene that sufferers lack.
Professor Robert MacLaren of Oxford University, who led the trial, said: "In truth we did not expect to see such dramatic improvements in visual acuity.
"It is still too early to know if the gene therapy treatment will last indefinitely, but we can say that the vision improvements have been maintained as long as we have been following up the patients, which is two years in one case."
The patients were treated in one eye only so doctors could accurately assess the effects of treatment.
Jonathan Wyatt, who received gene therapy said: "Now when I watch a football match on the TV, if I look at the screen with my left eye alone, it is as if someone has switched on the floodlights," he said.
"The green of the pitch is greener and the numbers on the shirts are much clearer."