A landmark stem cell study offers new hope for the treatment of blindness as well as bringing a major boost to the field of stem cell research.
The stem cell therapy trial, which took place in July 2011, successfully improved the eyesight of two women in the US, who were registered as blind.
Each patient had one eye injected with about 50,000 retinal pigment epithelium (RPE) cells that had been derived from embryonic stem cells.
One of the women, in her 70s went from being able to read 21 letters on a sight test chart to 28.
The other, in her 50s, went from only being able to detect hand movements to being able to see finger movements.
Scientists believe this could lead to a cure for age-related wet or dry macular degeneration, a form of blindness that leads to deteriorating central vision as a result of retinal cells dying. The condition affects around 1.5 million people a year in the UK.
A parallel European trial is being run at the Moorfield Eye Hospital in London, with patients suffering from Stargardt’s macular dystrophy, a rare and hereditary form of macular degeneration which eventually leads to blindness.
Marcus Hilton, a 34-year-old man from Wakefield, West Yorkshire was the first of 12 patients to be injected with retinal pigment epithelial (RPE) cells.
Mr Hilton received the injection in his right eye on Friday. It is too early for there to have been any effect as yet but he is hopeful about the results.
He said of the US findings: "I'm over the moon they have had early results in America showing this treatment could work.
"It could change many people's lives - to have some sight restored would be a dream come true."
Professor James Bainbridge, who is leading the European trial, said, as reported in the Telegraph: "There is real potential that people with blinding disorders of the retina, including Stargardt disease and age-related macular degeneration, might benefit in the future from transplantation of retinal cells.
"We are very pleased that the first transplant surgery has gone smoothly and look forward to seeing the results as the trial progresses over the next 2 years.
"While this is primarily a safety trial, we will have the opportunity to monitor engraftment of retinal cells and to assess any impact on sight."