Unseen Colors: Prevalence and Patterns of Color Vision Deficiency Among School Students of Bhairahawa, Nepal

Abstract

Introduction: Color vision deficiency (CVD), commonly referred to as color blindness, is a disorder of impairment in color perception, often due to an X-linked recessive genetic trait. While its prevalence varies across the globe, limited studies exist in the Nepali population. This study aimed to determine the prevalence of CVD among the school children of grades 6 to 10 in Bhairahawa, Lumbini, Nepal.

Methods: This descriptive cross-sectional study was conducted in October and November 2024, among 758 students from three secondary schools in Bhairahawa, selected by stratified random sampling. Students were tested using the 38-plate Ishihara chart under well-lit conditions. Parental consent was obtained before testing, and students with severe neurological disorders were excluded.

Results: Among 758 students, 53.95% were males. CVD was detected in 15 students (1.98%), comprising 13 males (3.18%) and 2 females (0.57%). Total color blindness was the most common type (6 cases, 1.47%), followed by protan (5 cases, 0.66%), deutan (2 cases, 0.26%), and combined red-green deficiency (2 cases, 0.26%). The male-to-female ratio was consistent with the expected X-linked inheritance pattern.

Conclusion: In the present study, 1.98% of school-going students of Bhairahawa from grades six to ten had color vision deficiency of different forms, with significantly higher prevalence of males. Total color vision defect was the most common, unlike typical global trends where red-green deficiency is most predominant, highlighting the need for larger epidemiological studies and school-based screening programs.