This clinical study tackled the problem of hyperbaric oxygen in patients with nonarteritic anterior ischemic optic neuropathy. Twenty-one patients were included in the study. The patients were divided into two groups: experimental and control. Experimental group consisted of 10 patients, who had been previously treated with corticosteroids, without significant success. In four patients with a clinical picture of PNO atrophy, medical steroid treatment failed to any significant improvement in visual acuity. In 6 patients, however, this treatment resulted in a significant improvement of both visual acuity and field of vision. These patients showed further improvement on control testing performed six month later. All patients from the control group were treated with corticosteroids per os and by local application, but without any significant improvement as revealed by visual acuity and visual field testing. Authors' results pointed the possibility of conservative treatment of patients with anterior ischemic optic neuropathy, especially those in whom steroid therapy had proved inefficient.