Prevalence and causes of visual impairment and blindness in three ecological regions of Nepal

Abstract

Background: Visual impairment and blindness are significant public health issues worldwide. The study aims to explore is the prevalence and causes of moderate to severe visual impairment and blindness across three ecological regions of Nepal. Methods: A comparative cross-sectional study was conducted in three districts covering all ecological regions of Nepal. Intensive training for health workers was provided to conduct door-to-door visits for visual acuity testing using Snellen chart and refer the abnormal cases for comprehensive ocular examination by technicians and ophthalmologists to diagnose and treat ocular morbidities. Collected data were analyzed using Statistical Package for Social Sciences and Stata software. Results: Altogether 5234 participants were enrolled in the study. The overall prevalence of moderate to severe visual impairment was 9.5% (4.7% in the Mountain district, 11.2% in the Hill district and 21.2% in the Tarai district), though the prevalence of MSVI was 1.5% in participants aged 15-49 years and 25.1% in those aged ≥50. The overall prevalence of blindness was 0.9%, and the prevalence of blindness in the 15-49 and ≥50 age groups was 0.2% and 2.3% respectively. Most cases of visual impairment and blindness (95.5%) were an avoidable cause, of which 93.7% were treatable and 1.8% were preventable. Overall, cataract was the leading cause of visual impairment and blindness (53.5%), followed by uncorrected refractive error (39.5%). Conclusion: The prevalence of visual impairment and blindness varied significantly with age, ethnicity and locality. The correction of refractive error and cataract surgery would reduce nine in ten cases of moderate to severe visual impairment and blindness. Key words: Epidemiology, Public health, visual, Optic and refraction