The sensitivity analysis confirmed the results showing higher ET-1 levels for POAG patients by a pooled mean difference of 0.44 pg/mL ET-1 (95% CI: −0.07–0.95, p < 0.001), after funnel plot evaluation and 5 outlier studies removals, with a moderate heterogeneity (I2 = 74%, p = 0.09) (Figure 3, Panel B). Here, EDN1 is linked to open-angle glaucoma.