Retrospective analysis of patients blinded by glaucoma has revealed a need to educate patients to the significance of premonitory symptoms, to investigate a higher incidence of blindness from open-angle glaucoma among blacks than whites, and to define the goals of therapy in relation to presenting pathology. Responding to this third need, circumstances of patients followed for 20 to 40 years with extensive documentation relating to open-angle glaucoma were analyzed. Some eyes with normal discs and fields were found to tolerate a tension of 30 mm Hg for many years without need of treatment. But, when abnormalities ranging from early glaucomatous cupping to advanced visual field defects were present on initial evaluation, progressive loss of field tended to occur at lower tensions. It appears that the worse the initial condition of the eye, the lower the tension needs to be to prevent further loss or blindness.