Projected clinical outcomes of glaucoma screening in African American individuals

Objectives: To project the clinical impact of routine glaucoma screening on visual outcomes in middle-aged African American individuals and help guide glaucoma screening policy. Methods: Using data from the Eye Diseases Prevalence Research Group and Baltimore Eye Study, we developed a microsimulation model to project visual outcomes in African American individuals screened for glaucoma under a national screening policy using frequency-doubling technology. Weprojected the impact of universal screening on glaucoma-related visual impairment (acuity worse than 20/40 but better than 20/200 in the better-seeing eye) and blindness (acuity 20/200 or worse in the betterseeing eye). The diagnostic characteristics of frequencydoubling technology and the hazard ratio for glaucoma progression in treated patients were informed by metaanalyses of randomized controlled trials. Results: Implementation of a national glaucoma screening policy for a cohort of African American individuals between the ages of 50 and 59 years without known glaucoma would reduce the lifetime prevalence of undiagnosed glaucoma from 50% to 27%, the prevalence of glaucoma-related visual impairment from 4.6% to 4.4% (4.1% relative decrease), and the prevalence of glaucomarelated blindness from 6.1% to 5.6% (7.1% relative decrease). We project the cost of the program to be $80 per screened individual, considering only the cost of frequency-doubling technology and confirmatory eye examinations. The number needed to screen to diagnose 1 person with glaucoma is 58. The number needed to screen to prevent 1 person from developing visual impairment is 875. Conclusions: Routine glaucoma screening for middleaged African American individuals is potentially clinically effective but its impact on visual impairment and blindness may be modest. However, we did not assess the impact on visual field loss.