Population-based glaucoma prevalence studies in Asians.

Glaucoma-related population-based studies from Japan, Mongolia, India, Singapore, Thailand, China, Bangladesh, Myanmar, Sri Lanka, and South Korea show a higher glaucoma prevalence in Asian patients, including a higher incidence of primary angle-closure glaucoma, than in white patients, although primary open-angle glaucoma (POAG) is still the most commonly reported. Among POAG, normal tension glaucoma predominates over high tension glaucoma, a distinctive finding. Risk factors for glaucoma in population-based studies in both Asian and white patients are similar, except that myopia is a greater risk factor in Asian patients. Diagnostic criteria differ among studies, some using the International Society of Geographic and Epidemiologic Ophthalmology (ISGEO) classification and others not. The devices used to observe the optic disk and test the visual field are also not uniform across studies. Moreover, the ages of patients, and whether rural or urban, were different. To allow reliable comparison of the results of epidemiologic studies, efforts to standardize the diagnostic criteria, devices, and the age range of the study population are required.