Metformin as a Neuroprotective Therapy for Glaucoma - A Randomized Controlled Trial

"To investigate whether metformin has a neuroprotective effect in patients with primary open-angle glaucoma by comparing the rates of change of average retinal nerve fiber layer ganglion cell inner plexiform layer (RNFL-GCIPL) thickness (primary outcome measure) between patients randomized to receive metformin versus those randomized to receive placebo.~To identify the risk factors associated with progressive RNFL-GCIPL thinning and progressive decline in visual field mean deviation in patients with glaucoma."

This study takes 24 months. Participants will have 12 visits within 24 months. All of the investigations will be carried out at Grantham Hospital and Hong Kong Eye Hospital. Patients will be randomly assigned in a 1:1 ratio to receive, twice daily, oral metformin 750mg (i.e. 1500mg/day) or identical-appearing oral placebo. The investigators and patients will be blinded to the treatment assignment. Participants will be followed up at 2-month intervals for 24 months.