Visual impairment in a rural Appalachian community. Prevalence and causes. A population-based survey of 1136 subjects aged 40 years and older was conducted in a rural valley of Kentucky to determine the nature and extent of visual disability in an underserved area of rural America. Data on corrected visual acuity and ocular history, along with demographic, socioeconomic, and health care utilization parameters, were gathered. Those subjects with an acuity below 20/60 in either eye underwent a comprehensive ophthalmologic examination. The prevalence of binocular blindness (acuity worse than 20/400 in the better eye) was 0.44% and of monocular blindness (acuity worse than 20/400 in one eye) was 3.3%, approximately twice the national rates. The chief cause of bilateral visual impairment was macular degeneration among men and cataract among women. Cataract, trauma, and amblyopia were the major causes of monocular visual impairment in both sexes. Risk factor analysis revealed younger age, higher education, active employment, access to a health care facility, and comprehensive health insurance coverage to be inversely associated with visual impairment. 