Prevalence of vision impairment and refractive error in rural Nepalese children under five years of age.

Abstract

Clinical relevance: Good vision is critical for childhood development and education. Pre-school vision screening is important for early detection and treatment of visual problems, and prevention of life-long vision loss.

Background: The aim of this study was to determine the prevalence of vision impairment (VI) and refractive error (RE) in rural Nepalese children under five years of age.

Methods: A cross-sectional study, using multistage random sampling, was conducted in the targeted children between 6 and 59 months old, identified by household visits from rural communities of Nepal. Eye examinations [visual acuity (VA), binocular vision, cycloplegic refractions, and anterior and posterior segments] were performed at community health centres. Refractive errors were recorded as a spherical equivalent (SE) and their prevalence was categorised as myopia (SE ≤ -1.00D) and hyperopia (SE ≥  +2.00D) and emmetropia with astigmatism (SE of astigmatism cases ≥ 1.50DC), and their associations with age, gender and ethnicity were explored.

Results: Of 2226 participating children, VA of 93.4% was reliably tested and among these, 5.9% had VI (presenting VA less than 6/18 in the better eye). Uncorrected RE accounted for 88% of VI. The overall prevalence of RE was also 5.9% (95% CI: 5.0-7.0), which included the prevalence of myopia, hyperopia and emmetropia with astigmatism of 2.4% (1.8-3.1), 2.7% (2.0-3.3) and 0.8% (0.4-1.2), respectively. The prevalence of overall astigmatism (total cases with ≥ 1.50DC) was 1.6% (1.1-2.1). Infants had significantly higher hyperopia compared to pre-schoolers [OR (95% CI: 4.9 (2.6-9.2)], while toddlers had higher likelihood of developing myopia [1.2 (0.9-1.5)]; however, gender and ethnicity had no significant associations.

Conclusions: The prevalence of VI was high and uncorrected RE was the main cause of VI in rural Nepalese children under five years of age. Early vision screening should be conducted in pre-school children to correct significant RE and avoid the risk of developing refractive VI and amblyopia.