Doctors in London have become the first in the world to cure blindness in children born with a rare genetic condition using a pioneering gene therapy.

The children had leber congenital amaurosis (LCA), a severe form of retinal dystrophy that causes vision loss due to a defect in the AIPL1 gene. Those affected are legally certified as blind from birth.

But after doctors injected healthy copies of the gene into their eyes with keyhole surgery that took just 60 minutes, four children can now see shapes, find toys, recognise their parents’ faces, and in some cases, even read and write.

“The outcomes for these children are hugely impressive and show the power of gene therapy to change lives,” said Prof Michel Michaelides, a consultant retinal specialist at Moorfields Eye hospital and professor of ophthalmology at the UCL Institute of Ophthalmology.

“We have, for the first time, an effective treatment for the most severe form of childhood blindness, and a potential paradigm shift to treatment at the earliest stages of the disease.”