Everyday diabetes medicine could treat common cause of blindness - medicalxpress

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Doctors have found that metformin, an everyday medicine for diabetes, is associated with less progression of age-related macular degeneration (AMD), the most common cause of blindness in western countries. In a recent study, people with diabetes over the age of 55 years taking metformin were 37% less likely to develop the intermediate stage of AMD over a five-year period compared to those not taking metformin.

The results appear in BMJ Open Ophthalmology.

AMD is a disease that affects the central retina or macular at the back of the eye. It eventually causes the light-sensitive tissue to die off (geographic atrophy, a form of dry AMD) or be damaged by abnormal blood vessel growth (wet AMD). Intermediate and advanced AMD affects 10–15% of people over 65 years of age (1.1 to 1.8 million people in the UK), and is the most common cause of blindness in high-income countries.

The annual cost of AMD is estimated to be £11.1 billion in the UK. Geographic atrophy has no treatment in the UK and Europe, while treatments for wet AMD are expensive and unpleasant (repeated injections into the eye).

The research from the University of Liverpool used pictures taken of the eyes of 2,000 people attending the routine diabetic eye disease screening program in Liverpool over five years. The researchers assessed whether AMD was present in the photographs and how severe it was, and then compared those taking metformin and those who were not. They also adjusted for factors that might bias the result, such as age, sex, and duration of diabetes. The odds of developing intermediate AMD over five years in the metformin group were 0.63 compared to the no-metformin group (95% confidence range 0.43 to 0.92).

A potential benefit from metformin in AMD has been suspected before, but this is the first study to grade AMD from eye photographs. Previous studies on metformin have used secondary information on AMD such as GP diagnostic codes, or insurance claims in the US.

Dr. Nick Beare, an eye doctor who led this research, says, "Most people who suffer from AMD have no treatment, so this is a great breakthrough in our search for new treatments. What we need to do now is test metformin as a treatment for AMD in a clinical trial. Metformin has the potential to save many people's sight." 

Provided by University of Liverpool  

by University of Liverpool

edited by Stephanie Baum, reviewed by Robert Egan 

Source: Everyday diabetes medicine could treat common cause of blindness