London: Hundreds of thousands of people who are registered blind have been offered new hope after scientists discovered stem cells in the eye that can be altered to pick up light.

Researchers found a reservoir of stem cells in an area called the corneal limbus. They have proven that, in the right environment, the cells can be transformed into photoreceptor cells that react to light. Scientists are hopeful that implanting the cultured stem cells in a damaged eye will reverse blindness.

It could offer a potential cure for hundreds of thousands of people suffering macular degeneration or retinitis pigmentosa, both of which are caused by the loss of photoreceptor cells. The researchers at the University of Southampton found that the cells even existed in the eyes of a 97-year-old, opening up the possibility that the treatment will work for the elderly.

“These cells are readily accessible, and they have surprising plasticity, which makes them an attractive cell resource for future therapies,” said Andrew Lotery, a professor at the university and a consultant ophthalmologist at Southampton General Hospital, who led the study, which is published in the journal Plos One.

“This would help avoid complications with rejection or contamination because the cells taken from the eye would be returned to the same patient. More research is now needed to develop this approach before these cells are used in patients.” The loss of photoreceptor cells causes irreversible blindness. Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world and affects around one in three people in Britain by the age of 75.

Around 513,000 people are in the late stage of AMD, a figure that is expected to rise by a third to nearly 700,000 cases by 2020. Almost two million people in the UK live with sight loss. There is currently no treatment for blindness caused by the loss of photoreceptors. The Southampton scientists have shown only that the concept works in the lab and are yet to implant the stem cells in a human patient.

Clara Eaglen, the RNIB’s eye health campaigns manager, said: “At RNIB we talk to people every day who tell us about the huge impact that losing their sight has on daily life, so this is very interesting research. “The study shows that you can grow stem cells and make them act like light sensitive cells, a big step forward in helping patients with conditions such as age-related macular degeneration where damage has occurred to the light sensitive cells. These cells can then be taken from a patient, changed, and replaced - reducing the risk of rejection which is exciting. “We are hopeful that stem cell technology will significantly change the way in which people with sight loss are treated over the next decade.”

— The Telegraph Group Limited, London, 2014