Prevalence and incidence
The prevalence (total number of individuals with a disease at a specific time) and incidence (number of new cases that develop during a specific period) of POAG vary widely across population-based samples owing to differences in ethnic and racial representation (Fig 3-1). In the Baltimore Eye Survey, the prevalence of POAG among white individuals ranged from 0.9% in those aged 40–49 years to 2.2% in those aged ≥80 years, whereas the prevalence among black individuals ranged from 1.2% to 11.3%, respectively. The overall population-based prevalence was 4–5 times higher among black individuals than white individuals.
In the Rotterdam Study, a longitudinal population-based study of northern Europeans, the observed prevalence was 1.1% among subjects ≥55 years of age. In the same study cohort, the incident risk of developing glaucoma at 10 years was 2.8%. In both the Baltimore Eye Survey and the Rotterdam Study, half of the subjects with glaucoma were unaware of their diagnosis.
Figure 1-3 The prevalence of primary open-angle glaucoma as a function of age and ethnicity.
(Courtesy of Tham YC, Li X, Wong TY, Quigley HA, Aung T, Cheng CY. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology. 2014;121:2081–2090.)
The prevalence of glaucoma in the Barbados Eye Study (a predominantly African Caribbean population) was 7% in individuals ≥40 years, and the 4-year incidence of glaucoma was 2.2%. Again, older age was found to be a major risk factor for the prevalence and incidence of glaucoma.
The observed prevalence of OAG in the Los Angeles Latino Eye Survey (LALES), a longitudinal population-based study of Latinos (mostly Mexican ancestry) ≥40 years of age, was 4.7%, with 75% unaware of their diagnosis at baseline. The prevalence among those 80 years or older was nearly 22%. The 4-year incidence rate of OAG was 2.3%.
In the Tajimi Study (Japan), the prevalence of POAG among subjects ≥40 years was 3.9%. The IOP was ≤ 21 mm Hg in 92% of those with POAG. The mean IOP in the nonglaucomatous eyes was 14.5 ± 2.5 mm Hg, about 2 mm Hg lower than observed in European-derived populations.
A meta-analysis estimated the global prevalence of POAG in 2013 to be 3.0% among persons 40–80 years of age. In this age group, the highest prevalence of POAG, an estimated 4.2%, is found in Africa. The same study estimated the prevalence of POAG in North America to be approximately 3.3%.
Leske MC, Connell AM, Wu SY, et al. Incidence of open-angle glaucoma: the Barbados Eye Studies. The Barbados Eye Studies Group. Arch Ophthalmol. 2001;119(1):89–95.
Tham YC, Li X, Wong TY, Quigley HA, Aung T, Cheng CY. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology. 2014;121(11):2081–2090.
Tielsch JM, Sommer A, Katz J, Royall RM, Quigley HA, Javitt J. Racial variations in the prevalence of primary open-angle glaucoma. The Baltimore Eye Survey. JAMA. 1991;266(3):369–374.
Varma R, Ying-Lai M, Francis BA, et al; Los Angeles Latino Eye Study Group. Prevalence of open-angle glaucoma and ocular hypertension in Latinos: the Los Angeles Latino Eye Study. Ophthalmology. 2004;111(8):1439–1448.
Population-based studies and prospective glaucoma clinical trials have identified a number of risk factors that are associated with POAG diagnosis and progression. The most widely accepted risk factors include higher IOP; lower ocular perfusion pressure; older age; lower central corneal thickness (thinner cornea); high myopia; and racial, ethnic, and genetic susceptibility. Other possible risk factors are discussed in Chapter 7.
Leske MC, Heijl A, Hyman L, Bengtsson B, Dong L, Yang Z; EMGT Group. Predictors of long-term progression in the Early Manifest Glaucoma Trial. Ophthalmology. 2007;114(11):1965–1972.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.