Thousands of people born with a faulty gene which makes them go blind have been offered new hope after a British man underwent the world’s first operation to deliver new DNA to his eyes and restore his sight.

Around 15,000 people in Britain suffer from x-linked retinitis pigmentosa, a deteriorating condition which brings a slow and irreversible loss of vision, and which is the leading cause of blindness in young people.

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.