Lifetime Risk of Visual Impairment Resulting from Glaucoma in Patients Initially Followed up for Elevated Intraocular Pressure

Purpose: To report the lifetime risk of visual impairment resulting from glaucoma in patients originally followed up in a 10-year prospective randomized study initiated in 1981 to assess patients with elevated intraocular pressure (IOP). Design: Retrospective patient chart review. Participants: Data on deceased patients who initially were followed up prospectively in the randomized controlled study and thereafter were followed up in ordinary clinical practice were collected until the end of 2017. Inclusion in the original study required an untreated IOP of 22 mmHg or more and 1 or more risk factors for glaucoma. Methods: Visual impairment, low vision, and blindness were defined according to the World Health Organization criteria. All eyes that became visually impaired were registered, including the date and cause of the impairment; the cumulative incidence of visual impairment corrected for competing risks was calculated; and the Kaplan-Meier method was used to analyze the importance of risk factors present at baseline for 1 eye per patient. Main Outcome Measures: The proportion of patients who became bilaterally visually impaired because of glaucoma, the cumulative incidence of glaucoma-related visual impairment in at least 1 eye, and potential baseline risk factors for visual impairment caused by glaucoma. Results: Seventy-seven of 90 patients (86%) included in the initial randomized study were deceased at the end of 2017. Four patients were lost to follow-up during the clinical follow-up. Of the 77 patients, 7 (9%) became bilaterally visually impaired and 2 of those 7 became bilaterally blind because of glaucoma. The cumulative incidence of glaucoma-induced visual impairment in at least 1 eye increased from 0.00 after 5 years to 0.22 (95% confidence interval [CI], -0.01 to 0.67) after 30 years. The cumulative incidence of glaucoma blindness in at least 1 eye increased from 0.00 after 5 years to 0.17 (95% CI, 0.10-0.54) after 30 years. No specific risk factor significantly increased the risk of visual impairment caused by glaucoma. Conclusions: Although the investigated patients showed elevated IOP and at least 1 additional glaucoma risk factor (i.e., they were high-risk patients), only a relatively small proportion of the patients with glaucoma demonstrated visual impairment. (C) 2019 by the American Academy of Ophthalmology