Moorfields Eye Hospital and the Institute of Ophthalmology have made the world's first attempt to treat blindness in children using gene therapy.
The research team conducting the first clinical trial to treat genetic sight disorders caused by the faulty gene RPE65 using gene therapy was led by Professor Robin Ali and included eye surgeon James Bainbridge and retinal specialist Professor Tony Moore.
The RPE65 defect stops the layer of cells in the retina from working and is responsible for Leber's congenital amaurosis, which is a type of inherited retinal degeneration.
The operation to correct this disorder involves injecting working copies of the defective gene into the retina. The technique has worked successfully under laboratory conditions using animals.
Researchers announced this week that operations have already taken place on young adults who developed the condition in childhood.
Bainbridge who led the surgical team said: 'It is very encouraging that we can deliver genes to an extremely fragile site in the eye without complications.'
Professor Ali added: 'We have been developing gene therapy for eye disease for almost 15 years but until now we have been evaluating the technology only in the laboratory. Testing it for the first time in patients is very important and exciting, and represents a huge step towards establishing gene therapy for the treatment of many different eye conditions.'
The research team said that it would be several months before they know whether their work has been successful. However, they believe that results from this first trial are likely to provide an important basis for many more gene therapy protocols in the future.
Optician clinical editor Bill Harvey commented: 'The pioneering use of a gene vector to treat a disease by a British team is certainly exciting news and likely to have a wide enough profile for patients of optical practices to be commenting on it in the coming weeks.
'The very specific nature of retinal degenerative disorders such as Leber's congenital amaurosis and many of the other retinitis pigmentosa conditions lend themselves well to such an intervention. It is quite possible that the progress of gene therapy to treat major disease is very much linked with eye disease research.
'As always with these breakthroughs it is important to temper some of the press headlines implying "blindness cures". This important step in moving from animal models, in which modest but significant visual improvement was noted, to human models is just the very first step on a long path and that "cures" remain elusive. However, long-term prospects for the treatment of much eye disease suddenly look improved.
'As gene loci for the expression of eye diseases such as glaucoma and macular degeneration become identified, gene therapy is likely to represent a key weapon against sight loss for future generations.'