Age-related macular degeneration (AMD) is the  most common cause of irreversible blindness for older people. A recently published case-control study examined people 55 years and older with newly diagnosed AMD , enrolling 312 404 people with AMD and matching them with 312 376 controls. Those with AMD had a slightly higher percentage of participants with diabetes (26.0%) compared with the control group (25.5%). The use of metformin was found to be associated with reduced odds of developing AMD (odds ratio [OR], 0.94 [95% CI, 0.92-0.96]), and  moreover the association was dose dependent: low to moderate doses of metformin showing the greatest potential benefit (dosages over 2 years: 1-270 g, OR, 0.91 [95% CI, 0.88-0.94]; 271-600 g, OR, 0.90 [95% CI, 0.87-0.93]; 601-1080 g, OR, 0.95 [95% CI, 0.92-0.98]). Doses of more than 1080 g of metformin over 2 years did not have reduced odds of developing AMD. Both the reduction in odds ratio and the dose-dependent response were preserved in a cohort consisting only of patients with diabetes. The authors suggest that metformin may help to prevent AMD and advocate for prospective clinical trials. See more details here.