SOD1 and open-angle glaucoma: To find out whether oxidative stress accompanies the increase in zinc concentration that was detected in POAG patients, we used randomly selected AH samples to analyze total antioxidant activity (AOA; the more severe oxidative stress, the less residual AOA), mediated by low-molecular-weight antioxidants, and the activity of key antioxidant defense enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPx) (Fig. 1d).