Between 1982 and 1991, inclusive, a total of 13718 patients were treated in the Department of Eye Diseases in Plovdiv University of Medicine. Cataract patients formed the most numerous group (19.71%), followed by those with diseases of the retina (9.53%), glaucoma (7.95%), uveitis (4.9%), diseases of the cornea (3.86%), malignant tumors of the eyelids and the eyeball (2.29%) and diseases of the optic nerve (1.54%). Of these 13718 patients, 1727 (12.58%) had monocular and binocular vision below 0.08. The patients with visual acuity from 0 to 0.03 were 1330 (9.69%). Nosologically, they were distributed as follows: glacoma-422 (3.07%), eye traumas-281 (2.04%), diseases of the retina-270 (1.96%), diseases of the cornea-89 (0.64%), cataract-80 (0.58%), uveitis-77 (0.56%), malignant tumors of the eyelids and the eyeball-66 (0.48%), and diseases of the optic nerve-45 (0.32%). Glaucoma was found to be the most common cause of blindness among the patients treated in the Department of Eye Diseases, followed by eye traumas and disease of the retina. The importance of the vascular factor in inducing blindness is undeniably great. It is the underlying cause of the open-angle glaucoma, the diseases of the retina and the optic nerve.