To assess the prevalence of refractive error and vision impairment in school age children
in the terai area of the Mechi zone in Eastern Nepal.
Random selection of village-based clusters was used to identify a sample of children
5 to 15 years of age. Children in the 25 selected clusters were enumerated through
a door-to-door household survey and invited to village sites for examination. Visual
acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility
evaluation, and anterior segment, media, and fundus examinations were done from May
1998 through July 1998. Independent replicate examinations for quality assurance monitoring
took place in all children with reduced vision and in a sample of those with normal
vision in seven villages.
A total of 5,526 children from 3,724 households were enumerated, and 5,067 children
(91.7%) were examined. The prevalence of uncorrected, presenting, and best visual
acuity 0.5 (20/40) or worse in at least one eye was 2.9%, 2.8%, and 1.4%, respectively;
0.4% had best visual acuity 0.5 or worse in both eyes. Refractive error was the cause
in 56% of the 200 eyes with reduced uncorrected vision, amblyopia in 9%, other causes
in 19%, with unexplained causes in the remaining 16%. Myopia -0.5 diopter or less
in either eye or hyperopia 2 diopters or greater was observed in less than 3% of children.
Hyperopia risk was associated with female gender and myopia risk with older age.
The prevalence of reduced vision is very low in school-age children in Nepal, most
of it because of correctable refractive error. Further studies are needed to determine
whether the prevalence of myopia will be higher for more recent birth cohorts.