Reduction in Glaucoma Risk With Metformin Appears Dose-Dependent
Julia Richards, PhD, a professor of ophthalmology and visual sciences at the University of Michigan in Ann Arbor, and colleagues collected 10 years of data on 150,016 people with diabetes. All were 40 or older at the start of the study. The investigators found that 3.9% of the participants developed OAG.
The researchers found that patients taking the highest amount of metformin had a 25% reduced risk of developing OAG compared with those not taking the medication. For every 1-gram increase in metformin taken, the risk was reduced by 0.16%. The researchers estimated that taking a standard dose of metformin (2 grams per day) for two years would reduce the risk for OAG by 20.8%. This risk reduction was seen even after accounting for lower blood glucose levels, the study authors said. Other diabetes medications were not associated with reduced risk of OAG.
"This study suggests that metformin may be affecting OAG risk on multiple levels, some involving improved glycemic control and some involving mechanisms outside glycemic control such as neurogenesis, inflammatory systems, or longevity pathways targeted by caloric restriction mimetic drugs," the authors write. "If confirmed by prospective clinical trials, these findings could lead to novel treatments for this sight-threatening disease."