Given the inconsistent reports of associations of different antidiabetic treatments with POAG risk in observational studies, we used drug target MR to simulate long‐term exposure to five approved T2D drugs with known mechanisms of action (sulfonylurea receptor 1 (ATP binding cassette subfamily C member 8 [ABCC8], peroxisome proliferator‐activated receptor γ [PPARG], dipeptidyl peptidase‐4 [DPP‐4], SGLT2, and GLP1R) in European and East Asian populations separately, to assess their causal effects on POAG. The gene discussed is ABCC8; the disease is open-angle glaucoma.