Prevalence of visual impairment, uncorrected refractive errors and effective refractive error coverage in Koshi Province, Nepal - Rapid Assessment of Refractive Errors.

Background/objective: To determine the prevalence of visual impairment (VI), uncorrected refractive errors (URE), and effective refractive error coverage among individuals aged 15-50 years in Koshi Province, Nepal.

Methods: A population-based cross-sectional study was conducted in Koshi Province in which 4800 participants were selected from 80 clusters. The study teams visited the selected households and conducted eye examinations. This included monocular unaided (and aided) visual acuity assessment using a Snellen chart with tumbling E optotypes at a distance of 6 meters. Near vision was assessed binocularly using the N notation chart at a fixed distance of 40 cm for each individual. Torchlight examination and distance direct ophthalmoscopy was done. VI was defined as presenting visual acuity worse than 6/12 in the better eye. URE was defined as presenting visual acuity worse than 6/12 and improving to 6/12 or better on using a pinhole. Near Vision Impairment was defined as binocular presenting near vision worse than N8 among those age 35 years and older.

Results: In total, 4057 were examined (84.5% response rate). The prevalence of VI was 3.52% (95% CI:2.89-4.13; n = 143). The prevalence of URE in the better eye was 1.95% (95% CI:1.54-2.42; n = 79). The Refractive Error Coverage and Effective Refractive Error Coverage were 34.8% and 31.3% respectively. The prevalence of NVI was 34.24% (95% CI: 32.1-36.40; n = 666).

Conclusion: The prevalence of VI and  URE was low, attributed to the availability and uptake of services in Koshi province in Nepal.