Examination-based population studies provide high-quality exams to small, defined patient populations. These studies provide the gold-standard data for examining and assessing total population prevalence. In contrast, claims and registry systems exclude patients who do not access clinical services as well as those who are undiagnosed. Examination-based estimates represent one of four types of data included in VEHSS.
VEHSS conducted a review of the published literature to identify existing measures of prevalence of vision loss, uncorrected refractive error (URE), age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma, cataract, and retinopathy of prematurity (ROP).
Demographic variables, study populations, condition definitions, and inclusion of condition types and stages varied widely among studies. The pages below summarize existing published prevalence estimates organized by data source. Many studies are not directly comparable because of differences in study design or population. This review makes no attempt to harmonize or directly compare estimates among studies.