Prevalence and correction of near vision impairment at seven sites in China, India, Nepal, Niger, South Africa, and the United States.

Abstract

To estimate the prevalence of near vision impairment and use of corrective spectacles among middle-aged and older adults in different settings and ethnic groups. Population-based, cross-sectional study. People aged ≥ 35 years were randomly selected with cluster sampling in 4 rural settings in Shunyi (China), Kaski (Nepal), Madurai (India), and Dosso (Niger); 1 semi-urban area in Durban (South Africa); and 2 urban settings in Guangzhou (China) and Los Angeles (USA). Near visual acuity (VA), with and without presenting near correction, was measured at 40 cm using a logMAR near vision tumbling E chart. Subjects with uncorrected binocular near VA ≤ 20/40 were tested with plus spheres to obtain the best-corrected binocular VA. A total of 17 734 persons aged ≥ 35 years were enumerated and 14 805 (83.5%) were examined. The age- and sex-standardized prevalence of uncorrected near vision impairment (VA ≤ 20/40) ranged from 49% in Dosso to 60% in Shunyi and Guangzhou, 65% in Kaski and Los Angeles, and 83% in Madurai and Durban. The prevalence of near vision impairment based on best-corrected visual acuity was less than 10% in Guangzhou, Kaski, Durban, and Los Angeles, but as high as 23% in Madurai. In multiple logistic regression models, uncorrected near vision impairment was associated with older age (odds ratio [OR] = 1.14, P < .001) and female sex (OR = 1.12, P = .027), but not with educational level (OR = 1.01, P = .812). Over 90% of people in need of near refractive correction in rural settings did not have the necessary spectacles. These rates were 40% in urban settings. By 50 years of age, the majority of people suffer from near vision impairment, most of which can be corrected optically. Over 90% of those in need of near refractive correction in rural settings do not have the necessary spectacles.