• The epinephrine pressure reduction was determined in 32 patients with elevated intraocular pressure (IOP) and 18 patients with untreated chronic open-angle glaucoma. The prevalence of responders was 53% of those patients with elevated IOP and 56% in those patients with open-angle glaucoma. This lack of difference between the two groups is suggestive of the need for caution before applying epinephrine in clinical practice as a predictive factor of future field loss.