Frequency of under-corrected refractive errors in elderly Chinese in Beijing.

Purpose: The aim of the study was to evaluate the prevalence of under-corrected refractive error among elderly Chinese in the Beijing area.

Methods: The population-based, cross-sectional, cohort study comprised 4,439 subjects out of 5,324 subjects asked to participate (response rate 83.4%) with an age of 40+ years.