Metformin use in people with diabetes was linked to a significantly lower risk of developing intermediate age-related macular degeneration.
Metformin, a medication widely prescribed to manage diabetes, may also be linked to the slower progression of age-related macular degeneration (AMD), the leading cause of blindness in Western countries.
Among people with diabetes who were older than 55, those taking metformin had a 37% lower chance of developing intermediate AMD over a five-year period compared with individuals who were not using the medication.
A major cause of vision loss
AMD affects the central portion of the retina, known as the macula, located at the back of the eye. As the disease advances, it damages the light-sensitive tissue that allows the eye to detect fine detail. In some cases, this tissue gradually deteriorates (geographic atrophy, a form of ‘dry’ AMD).
In other cases, abnormal blood vessels develop and damage the retina (‘wet’ AMD). Intermediate and advanced AMD occurs in about 10 to 15 percent of people over the age of 65 (1.1 to 1.8 million people in the UK), and it remains the most common cause of blindness in high-income countries.
AMD also carries a substantial economic burden. In the UK alone, the condition is estimated to cost £11.1billion each year. Geographic atrophy currently has no approved treatments in the UK or Europe, and therapies available for wet AMD can be difficult for patients because they often require repeated injections directly into the eye.
Eye screening data reveals protective link
The University of Liverpool conducted the study using retinal photographs from about 2,000 people who participated in Liverpool’s routine diabetic eye disease screening program over a period of five years. The images were examined to determine whether AMD was present and to measure how advanced the disease had become. The analysis compared participants who were taking metformin with those who were not.
The investigators also adjusted their analysis to account for factors that might influence the results, including age, sex, and how long a person had lived with diabetes. Over the five-year observation period, the likelihood of developing intermediate AMD in people taking metformin was 0.63 compared with those not taking the medication (95% confidence range 0.43 to 0.92).
Scientists have previously suggested that metformin might have protective effects against AMD. However, earlier research relied on indirect indicators such as general practitioner diagnostic codes or insurance claim records in the United States. This study is the first to evaluate AMD severity directly by grading retinal photographs.
Common diabetes drug may protect vision
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.”
Reference: “Metformin and incidence of age-related macular degeneration in people with diabetes: a population-based 5-year case-control study” by Dewi Fathin Romdhoniyyah, Ayesh Alshukri, David G Parry, Simon Harding and Nicholas A V Beare, 2 February 2026, BMJ Open Ophthalmology.
DOI: 10.1136/bmjophth-2025-002339
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