A GROUNDBREAKING stem cell trial is offering hope to patients who face going blind as a result of scarring to their eyes. 

The study, which recruited patients from Edinburgh, Glasgow and Liverpool, extracted stem cells from the corneas of deceased donors and used them to grow new tissue for transplant. 

A normal healthy cornea - the protective layer which covers the eye - is transparent.

However, it becomes scarred and cloudy when specialised stem cells are lost as a result of a condition called limbal stem cell deficiency (LSCD). 

The condition is comparatively rare in the UK - affecting around 200 people in Scotland - but causes severe vision loss, as well as chronic pain and redness. It can result from damage to eye from chemicals or heat, or be caused by a disease called aniridia.

The study, led by Edinburgh University and Scottish National Blood Transfusion Service, is believed to be the first in the world to compare stem cell and non-stem treatments in a randomised control trial, the gold standard for gauging effectiveness. 

Sixteen patients were split into two groups with both given eye drops and medicines to suppress their immune system to reduce transplant rejection. One group was also given the stem cells. 

The results showed that the patients given the stem cells showed "significant, sustained" repair to their eyes' surface which was not seen in the patients in the control group.

A total of 13 patients completed the study - eight in the stem cells group and five in the control group.

In the stem cell group, five out of eight had improved vision at the end of the 18 month study, compared to four out of five in the control group. 

There was "no significant difference" in visual acuity scores between the stem cell and control group, but the researchers said the approach warrants further investigation as the sample size was small. 

Dr Ashish Agrawal, a consultant ophthalmologist in NHS Lothian, who helped lead the study said two of his patients had experienced fairly substantial improvements in their sight.

He said: "The two patients I'm talking about had vision in terms of being able to make out hand movements in front of their eyes, close to face.

By the end of the study, they had more of a navigational vision - which means they can get around. It's not to the extent of being able to drive or anything, but being able to do day to day tasks and being able to see.

"These patients really have very poor vision -  maybe we can't give them legal driving standard vision, but we can keep them functional. 

"Until now there hadn't been much we can do for these patients. They have very poor vision. So if we can improve their vision to a certain extent, and keep them functional, that's why I think this trial is important. Because it gives these patients some hope."

The team suggest that the immune system could play a driving role in some forms of LSCD, but caution that more research is needed. 

The finds are published in Stem Cells Translational Medicine. 

Baljean Dhillon, Professor of Clinical Ophthalmology at the University of Edinburgh’s Centre for Clinical Brain Sciences, who led the study, said: “The findings from this small study are very promising and show the potential for safe stem cell eye surgery as well as improvements in eye repair.

“Our next steps are to better understand how stem cells could promote tissue repair for diseases that are extremely hard to treat and if, and how, they could help to restore vision.”