Common Diabetes Drug Cuts Vision Loss Risk by 37%

Millions of people facing blindness may have hope in an unexpected place: their medicine cabinet.

Researchers at the University of Liverpool discovered that metformin, a common diabetes medication taken by millions worldwide, significantly slows the progression of age-related macular degeneration (AMD). The disease is the leading cause of blindness in high-income countries, affecting up to 1.8 million people in the UK alone.

The five-year study followed 2,000 people over age 55 attending routine diabetic eye screenings in Liverpool. Those taking metformin were 37% less likely to develop intermediate AMD compared to those not taking the drug. The findings appear in BMJ Open Ophthalmology.

AMD destroys the central retina at the back of the eye, gradually stealing away vision. It affects 10 to 15% of people over 65, costing the UK an estimated £11.1 billion annually. Current treatments are either nonexistent or involve painful, expensive repeated injections into the eye.

What makes this discovery so exciting is that metformin is already proven safe, affordable, and widely available. Unlike previous studies that relied on insurance claims or GP codes, this research directly examined eye photographs to grade AMD severity. The team controlled for factors like age, sex, and how long people had diabetes to ensure accurate results.

The Bright Side

Most people with AMD currently have no treatment options at all. Geographic atrophy, one form of the disease, has zero approved treatments in the UK and Europe. Wet AMD treatments require patients to endure regular injections directly into their eyes at significant cost.

Metformin costs pennies per pill and has been safely used for decades. If clinical trials confirm these findings, doctors could immediately start prescribing an existing medication to protect vision in millions of older adults. The drug's safety profile is well understood, and most people tolerate it without serious side effects.

Dr. Nick Beare, the eye doctor who led the research, calls it "a great breakthrough in our search for new treatments." His team is now preparing clinical trials to test metformin specifically as an AMD treatment in people who don't have diabetes.

The discovery joins growing evidence that metformin offers benefits beyond blood sugar control, including potential protection against dementia, long COVID, and other age-related conditions. For the millions watching their vision slowly fade, this everyday diabetes pill could be tomorrow's sight-saving treatment.