The clinical features of 290 patients with scleral inflammation were reviewed to determine whether a classification based on the anatomical site and clinical appearance of the disease at presentation reflected its natural history. The authors' results confirm that the majority of patients remain in the same clinical category throughout the course of their disease. Of the 104 (35.9%) patients who experienced a recurrence of their disease, only 12 had progressed from diffuse to nodular disease, and 10 patients who originally had nodular disease developed scleral necrosis. Patients with necrotizing scleritis were older than patients in the other groups and more frequently had an associated systemic disease than patients with either diffuse or nodular disease; necrotizing scleritis was the most difficult disease to treat. Diffuse anterior scleritis had a lower incidence of visual loss (9%) than either nodular scleritis (26%) or necrotizing disease (74%), and, therefore, the authors consider nodular scleritis a disease of intermediate severity between diffuse scleritis and necrotizing disease. In this series, 12% of patients presented with posterior scleritis, and visual loss was most frequent in this group (84%).