In this meta-analysis consisting of 39 eligible studies, AHTN use was associated with an increased risk of KC based on estimates that accounted for hypertension (RR 1.19, 95% confidence interval (CI) 0.93–1.52 for angiotensin-converting enzyme inhibitor; RR 1.15, 95% CI 1.00-1.31 for angiotensin receptor blocker; RR 1.09, 95% CI 1.03–1.16 for beta-blocker, RR 1.40, 95% CI 1.12–1.75 for calcium channel blocker (CCB); RR 1.36, 95% CI 1.20–1.55 for diuretic; and RR 1.40, 95% CI 1.13–1.75 for non-classified AHTN). The gene discussed is ACE; the disease is keratoconus.