Screening for Open-Angle Glaucoma and Its Effect on Blindness

Abstract

Purpose: To evaluate the effect of population screening on low vision and blindness from open-angle glaucoma.

Design: Retrospective cohort study.

Methods: A large population-based screening for glaucoma was conducted in Malmö, Sweden, from 1992 to 1997. A total of 42,497 subjects were invited, of which 32,918 were screened, and 9,579 were non-responders (ie, did not participate). The records of glaucoma patients who had visited the Department of Ophthalmology at Malmö University Hospital from January 1, 1987, to December 31, 2017, were reviewed. Patients diagnosed at or after the screening were assessed for moderate or severe vision impairment, here called low vision, or blindness by the World Health Organization definition. Selection bias was corrected by creating a group of potential screening participants from a comparison group of clinical patients. Main outcome measures were the risk ratios of the cumulative incidence for bilateral low vision or blindness caused by glaucoma in screened patients compared with the potential participants.

Results: The cumulative incidence of blindness was 0.17% in the screened population versus 0.32% among the potential participants; and for low vision 0.25% versus 0.53%. The risk ratio (95% confidence interval) between the two was 0.52 (0.32-0.84) for blindness and 0.46 (0.31-0.68) for low vision. There were no differences between the proportions of potential confounders in the comparison group and those in the non-responders.

Conclusions: The results suggest that population screening may reduce bilateral low vision and blindness caused by glaucoma by approximately 50%.