Patients with diabetes who used metformin for at least five consecutive years showed a decreased risk of developing age-related macular degeneration (AMD), particularly the dry form, according to new research.

Study Details

Researchers from the Keck School of Medicine of the University of Southern California in Los Angeles conducted a retrospective cohort study. the study, lead by Alexander T.Hong,examined the connection between metformin use and AMD risk in diabetic patients. The findings were published online Aug. 11, 2025, in Ophthalmology Retina.

The study included 7496 patients aged 60 or older with diabetes,all of whom had at least two eye care visits more than a year apart. none of the participants had an existing AMD diagnosis at any visit. The researchers compared 3748 patients who used metformin at least once a year for five or more consecutive years to a matched group of 3748 patients who used metformin for fewer years or not at all. The primary focus was the growth of AMD after the second eye exam.

“Yearly metformin exposure for at least 5 years was associated with a decreased risk of developing AMD.”

Key Findings

The study revealed that AMD developed in a