London: British doctors have restored eyesight by using stem cells to replace damaged cells.

Although the results have delighted experts, the charity the Royal National Institute for the Blind warned that sufferers of blindness should not raise their hopes until further trials are carried out.

The treatment could also help sufferers of macular degeneration – the most common cause of blindness in the elderly – and those who have lost their sight as a complication of diabetes.

The researchers, from University College London and London’s Moorfields Eye Hospital, used stem cells – basic cells with the ability to turn into different types of tissue – to restore the vision in blind mice.

The cells were injected into the back of the eye where they replaced damaged photoreceptors – the tiny light-sensitive cells on the retina.

Until now, there was no way of reversing the damage – and previous stem cell transplants had failed.

Central to the success of the technique was the selection of cells which were slightly more mature than those tried by other scientists.

These cells turned into photoreceptors and successfully connected with the nerves leading to the brain. By shining light into the animals’ eyes, the researchers were able to show that vision had been restored to around a quarter of normal levels. Increasing the number and type of cells transplanted could improve sight even further.

The scientists caution that the technique is still in its infancy. But Dr MacLaren, of Moorfields Eye Hospital, said: ‘This research is the first to show photoreceptor transplantation is feasible. We are now confident that this is the avenue to pursue to uncover ways of restoring vision to thousands.’