British man has operation to deliver modified DNA to his eyes

The back of the right eye from a patient with X-linked retiniis pigmentosa

A British man with retinitis pigmentosa has had the world’s first operation to deliver new DNA to his eyes and restore his sight.

Around 15,000 people in Britain have retinitis pigmentosa, a deteriorating condition which is currently untreatable and leads to a slow and irreversible loss of vision.

Loss of sight occurs because a gene responsible for maintaining the light sensitive cells at the back of the eye is missing half of its DNA code.

But scientists can now replace the code using a groundbreaking technique which reprogrammes the gene in the lab, then delivers the healthy DNA into the eye, via a harmless virus.

This operation marks an exciting step forward in the treatment of retinal diseases. 

A 29-year-old man became the first person in the world to undergo the procedure at Oxford Eye Hospital and is now recovering.

Robert MacLaren, Professor of Ophthalmology at the University of Oxford, who is leading the trial, said: "He is doing well and now at home, but we will have to wait a few years to know if it has stopped his retina from degenerating. 

Retinitis pigmentosa affects 1 in 4000 people, with symptoms that typically appear between age 10 and 30. Night vision and peripheral vision go first, as the photoreceptors active in low light – the 'rods' – start to degenerate.

Eventually the condition affects the 'cones' – the photoreceptors responsible for central, detailed, colour vision, causing complete sight loss.

Doctors want to enroll at least 24 more patients in the trial to find out if the technique is safe and effective.