Irish and UK scientists have discovered that a drug that was originally developed to treat cardiovascular disease, could reduce diabetes-related blindness.

An estimated 422 million people worldwide have diabetes and a common complication of the disease is vision loss. Diabetic macular oedema is one of the most common causes of blindness in the western world and affects around 7% of people with diabetes.

However, scientists from Queen's University Belfast and University College London have found that the drug, Darapladib, is able to inhibit an enzyme - Lp-PLA2. This is increased in people with diabetes and is known to cause blood vessel leakage in the eye which leads to the retina swelling up, followed by severe vision loss.

A common treatment for diabetic macular oedema is an injection of a drug directly into the eye every four to six weeks. This treatment does not work on around half of those with this eye disease and is very expensive.

This latest discovery shows that Darapladib in tablet form has the potential to reduce the need for these frequent injections.

"Diabetes-related blindness is caused by high blood sugar levels damaging the blood vessels in the retina. We have found that an enzyme called Lp-PLA2, which metabolises fats in the blood, contributes to blood vessel damage and leakiness in the retina. The drug, Darapladib, acts as inhibitor of Lp-PLA2, and was originally developed for cardiovascular disease.

"Based on our breakthrough, we are now planning a clinical trial and if successful we could soon see an alternative, pain-free and cost-effective treatment for diabetic-related blindness," explained Prof Alan Stitt of Queen's University.

The scientists also noted that this drug has the potential ‘to be effective for patients what currently do not respond to standard treatment'.

Details of these findings have been published in the journal, Proceedings of the National Academy of Sciences.