An Overview of Ophthalmologic Survey Methodology in the 2008-2015 Korean National Health and Nutrition Examination Surveys.

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national program designed to assess the health and nutritional status of the noninstitutionalized population of South Korea. The KNHANES was initiated in 1998 and has been conducted annually since 2007. Starting in the latter half of 2008, ophthalmologic examinations were included in the survey in order to investigate the prevalence and risk factors of common eye diseases such as visual impairment, refractive errors, strabismus, blepharoptosis, cataract, pterygium, diabetic retinopathy, age-related macular degeneration, glaucoma, dry eye disease, and color vision deficiency. The measurements included in the ophthalmic questionnaire and examination methods were modified in the KNHANES IV, V, and VI. In this article, we provide detailed information about the methodology of the ophthalmic examinations in KNHANES in order to aid in further investigations related to major eye diseases in South Korea.