ET-1 was significantly elevated in the aqueous humor of patients in the POAG (mean ± SD: 7.8 ± 5.1 pg/mL; p = 0.002) and NTG cohorts (6.1 ± 3.0 pg/mL; p = 0.030) compared to the control (4.0 ± 1.9 pg/mL). This evidence concerns the gene EDN1 and open-angle glaucoma.