Purpose: To investigate blindness in patients with treated open-angle glaucoma (OAG) and risk factors for blindness.
Design: Retrospective observational case series.
Participants: One hundred eighty-six patients seen between April and November 2000 at the University of Washington Medical Center Eye Clinic, diagnosed in 1975 or later, and treated for at least 2 years for OAG.
Methods: Chart review with evaluation of visual acuity and visual field. Kaplan-Meier survival analysis was used to estimate the risk of blindness in one and both eyes. Variables considered to be possible risk factors for blindness were evaluated using chi-square test, t test, and Cox proportional hazards regression analysis.
Main outcome measures: Blindness, defined as visual acuity of 20/200 or worse, and/or continuous constriction of the visual field to 20 degrees or less in all four quadrants with a size III4e Goldmann stimulus or the equivalent on automated perimetry, allowing a higher threshold level on one point in one quadrant on automated perimetry.
Results: The mean duration of disease was 10.2 +/- 4.9 years. Twelve patients were blind in at least one eye from OAG at diagnosis. Nineteen other patients became blind in at least one eye from OAG, and three patients became bilaterally blind from OAG. The Kaplan-Meier estimate for blindness at 15 years in one eye was 14.6%, and in both eyes was 6.4%. Noncompliance with the treatment regimen (P = 0.016) and worse initial visual field loss (P < 0.0001) were significantly associated with development of blindness. Nonwhite race was associated with blindness (P = 0.014) when all blindness, including that found at diagnosis, was considered in the analysis.
Conclusions: Bilateral blindness from chronic OAG was uncommon in this population of treated patients diagnosed in 1975 or later. Of patients with a blind eye, 39% were blind at diagnosis, and worse visual field loss at diagnosis and noncompliance were associated with development of blindness.