A PIONEERING gene therapy is giving hope to people with common forms of blindness including macular degeneration and retinitis pigmentosa.

A clinical study by University of Oxford researchers has found gene therapy has restored some vision to patients who were going blind for as long as four years.

The therapy, which involves injecting a virus into the eye to help cells regenerate, has been trialled on six people with the rare disorder choroideremia at Oxford’s John Radcliffe Hospital.

The gene therapy was designed to slow or stop sight loss but the results, published in the New England Journal of Medicine, show two of the patients experienced a significant improvement in vision that was sustained for at least four years, despite a decline in their untreated eyes over this period.

A further three maintained their vision in their treated eyes in this period and the sixth patient, who received a lower dose, had a slow decline in vision in both eyes.

It is hoped the gene therapy would be applied to patients early in the disease process to prevent sight loss because the treatment is expected to be long lasting.

Professor Robert MacLaren, the lead investigator of the study, said the results were proof gene therapy could work long-term.

“Even sharpening up the little bit of central vision that these patients have can give them considerable independence,” Prof MacLaren said.

Dr Stephen Caddick, Director of Innovation at the Wellcome Trust, said this was the first time they had seen what appeared to be a permanent change in vision after one round of treatment.

“It’s a real step forward towards and era where gene therapy is part of routine care for these patients.”

Jonathan Wyatt, the first patient in the world to be treated with this gene therapy, is still sight impaired but the level of vision in his treated left eye has doubled and been maintained for four years so far.

Jonathan, a 68-year-old retired barrister from Bristol, could read 23 letters in eye chart tests prior to the operation but after 3.5 years he could read 44.

He said it had made him more independent and without the therapy he would feel cautious about train journeys on his own and stay at home more.

Joe Pepper, a 24-year-old teacher from Croydon who was the last patient to receive the gene therapy, said when he did the reading chart test he could read four more lines more than ever before.

“I will remember that day for the rest of my life. I laughed and shed a tear. It was special,” Joe said.

“Six months on from the surgery the results have been more than I ever imagined.”

He said he could now see defined features of people when looking into the distance and had the confidence to go out after dark.

The trial was funded by the Department of Health and the Wellcome Trust.

A follow on trial of 30 more patients has been funded by the Efficacy and Mechanism Evaluation Programme, a Medical Research Council and NIHR partnership.