Objective: To determine the longitudinal trends in the probability of blindness due to open-angle glaucoma (OAG) in Olmsted County, Minnesota, from 1965 to 2009.
Design: Retrospective, population-based cohort study.
Participants: All residents of Olmsted County, Minnesota (aged ≥ 40 years) who were diagnosed with OAG between January 1, 1965, and December 31, 2000.
Methods: All available medical records of every incident case of OAG were reviewed until December 31, 2009, to identify progression to blindness, defined as visual acuity ≤ 20/200 or visual field constriction to ≤ 20°. Kaplan-Meier analysis was used to estimate the cumulative probability of glaucoma-related blindness. Population incidence of blindness within 10 years of diagnosis was calculated using US Census data. Rates for subjects diagnosed in the period 1965-1980 were compared with rates for subjects diagnosed in the period 1981-2000 using log-rank tests and Poisson regression models.
Main outcome measures: Cumulative probability of OAG-related blindness and population incidence of blindness within 10 years of diagnosis.
Results: Probability of glaucoma-related blindness in at least 1 eye at 20 years decreased from 25.8% (95% confidence interval [CI], 18.5-32.5) for subjects diagnosed in 1965-1980 to 13.5% (95% CI, 8.8-17.9) for subjects diagnosed in 1981-2000 (P = 0.01). The population incidence of blindness within 10 years of the diagnosis decreased from 8.7 per 100,000 (95% CI, 5.9-11.5) for subjects diagnosed in 1965-1980 to 5.5 per 100,000 (95% CI, 3.9-7.2) for subjects diagnosed in 1981-2000 (P = 0.02). Higher age at diagnosis was associated with increased risk of progression to blindness (P < 0.001).
Conclusions: The 20-year probability and the population incidence of blindness due to OAG in at least 1 eye have decreased over a 45-year period from 1965 to 2009. However, a significant proportion of patients still progress to blindness despite recent diagnostic and therapeutic advancements.
Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.