Prevalence of glaucoma in the United States: The 2005 - 2008 National Health and Nutrition Examination Survey

Abstract

Purpose: To estimate the prevalence of glaucoma in the US populaiton using clinical assessment of fundus photography, to assess risk factors associated with confirmatory defects on frequency doubling technology (FDT) visual field testing, to estimate the prevalence of glaucoma awareness, and to identify risk factors for being unaware of having glaucoma.

Methods: Cross-sectional study representative of the US population of 5,746 men and women 40 years of age and older participating in NHANES 2005 - 2008. Fundus photographs with a cup-to-disk ratio (CDR) ≥ 0.6 on initial grading were re-graded by three glaucoma specialists to adjudicate the presence of glaucoma using clinical criteria and a formal algorithm to resolve discrepancies. Study participants also underwent a 19-point supra-threshold screening test using the N-30-5 pattern on the Matrix FDT.

Results: The estimated overall prevalence of glaucoma in the US, civilian, non-institutionalized population 40 years of age and older is 2.0% (95% CI, 1.6 - 2.5%). Glaucoma affects 2.3 million individuals, including 1.1 million women, 1.2 million men, 1.8 million subjects 60 years of age and older, and 0.7 million minority subjects. The prevalence of glaucoma is highest in Non-Hispanic Blacks, followed by Non-Hispanic Whites, Mexican Americans and others. Over half of participants with glaucoma are unaware that they have the disease.

Conclusions: The prevalence of glaucoma based on objective fundus photography assessment in the general US population 40 years of age an older is 2.0%, consistent with other major population-based surveys. Approximately half of glaucoma cases were previously undiagnosed, underscoring that the development of reliable and cost-effective screening algorithms is a clear public health and clinical priority. Studies to determine whether and how to identify undiagnosed glaucoma are an important next step.