Dr Julie Daniels is leading the research team. She said: “Before the surgery the patients were barely able to recognise when someone was waving a hand in front of their face but we have restored their vision to the point they can read three to four lines down the eye chart.”

The patients lost their sight through chemical burns or the rare genetic disease aniridia. They had injuries to the limbal cells in their eyes. These cells form the transparent layer on the outside of the cornea.

Dr Daniels explained why this damage causes blindness: “Their cornea becomes opaque, blood vessels grow across it and their eyes become inflamed and they can’t see anymore. It is very painful.” She continued, “By replacing the limbal stem cells, the cornea begins to clear up as the cells are replaced with the healthy transparent layer again.”

She explained that the procedure has not yet resulted in complete restoration of sight, though patients have reported improvements, including six who show unprecedented recovery.

Scientists at Moorfields Eye Hospital hope to use stem cells to treat other causes of blindness. They anticipate creating small patches of retina cells that detect light at the back of the eye.

Supporters of the research emphasize that while these treatments are groundbreaking, they will require a great deal of research, and therefore time, before they will become widely used.

Read more at the Telegraph.