A woman in the UK has become the first in the world to undergo an eye- operation that uses an embryonic stem cell "patch" technique, which experts hope will cure blindness in some patients.
The procedure involves taking a single stem cell from an embryo and growing it into a "patch", or sheet of cells, that can be transplanted into the eye.
The woman, who has age-related macular degeneration (AMD), does not wish to be named but there have been no complications to date.
AMD is a painless eye condition that causes the loss of central vision. It affects more than 600,000 people in the UK and is the leading cause of blindness in adults.
The operation was carried out last month by Professor Lyndon Da Cruz from Moorfields Eye Hospital in London.
He said the the new technique was exciting as it showed there was the potential for a treatment, rather than being simply a "theoretical proof".
To create the patch an embryo is grown in the lab to create a single layer of retinal pigment epithelium cells.
These cells form a thin sheet that lines the inside of the eye, under the retina. A healthy layer is critical to normal sight, and when these cells are damaged or lost, they are thought to lead to AMD.
A study on 10 patients with a form of the disease known as wet AMD has been launched, with the hope of extending the findings to people with the more common dry AMD.
The operation is a major milestone in the London Project to Cure Blindness, which is a partnership between Moorfields, the University College London Institute of Ophthalmology and the National Institute for Health Research.
But there is still some way to go.
Professor Graham McGeown, from Queen's University Belfast, said: "The planned study is too small to establish whether this really will work as a mainline treatment but such a pilot study is a necessary first step and, if this is successful, a larger clinical trial would be justified."