Advances in stem cell treatment may make it possible to cure blindness. This was demonstrated when eight partially blind patients, who participated in the trial of a new treatment to restore vision at the North East England Stem Cell Institute (NESCI), Newcastle, reported radically improved vision among other benefits.

Among the patients was 38-year-old Russell Turnbull from Consett, Durham. He lost most of the vision in his right eye in 1994, when he had ammonia sprayed on his face even as he attempted to intervene in a quarrel on a bus. His cornea was burnt as a result of this leading to clouded sight, sensitivity to light and pain while blinking.

The chemical burn damaged Turnbull's limbal stem cells - a collection of special cells in the eye that are important to maintain the smooth, transparent outer surface of the cornea. As a result he suffered a limbal stem cell deficiency (LSCD), a condition that causes the retina to become cloudy and rough, causing pain and sensitivity to light.

Doctors used limbal stem cells from Turnbull's functioning eye to grow more of these in a laboratory. These cells were then spread over a human amniotic membrane, which is the tissue that generally supports fetuses while they are in the womb. The stem cell grafts were then used to replace the damaged corneal tissue, enabling Turnbull to get back his sight.

Turnbull who, apart from blindness, also complained of pain and constant watering, has now almost recovered normal vision with no pain, just about a year and a half after the treatment. He has started working again and has resumed jet skiing and riding, hobbies which he had had to give up after the accident.

The trial of the treatment procedure was carried out by Dr Francisco Figueiredo and Dr Sajjad Ahmad, of the Royal Victoria Infirmary. All eight patients, with blindness in one eye due to LSCD, reported improvement about 19 months after the treatment.

Currently the treatment procedure is only useful for patients with one undamaged eye, from which stem cells can be removed and grown, explained Dr Ahmad. However in the future it may even be possible to use cells from other parts of the body to grow limbal stem cells to treat patients with bilateral blindness, he hoped.

About eight million people worldwide are estimated to suffer from blindness induced by corneal cloudiness each year. A report on the new treatment has been published in the journal Stem Cells.