Tribal Odisha Eye Disease Study (TOES) report # 5: Comparison of prevalence and causes of visual impairment among tribal children in native and urban schools of Odisha (India)

PURPOSE: To compare the prevalence and causes of blindness and visual impairment in tribal school students in the rural day-care and in a residential urban school. METHODS: This was a cross-sectional comparative study. The 4-Stage screening in the native habitat of the tribal students performed in the school and hospital involved the trained school teachers, optometrists, comprehensive ophthalmologist, and pediatric ophthalmologist. The 2-Stage screening in the urban school involved only the optometrists and pediatric ophthalmologist. In both instances, vision (presenting and best corrected) was recorded and refraction performed. In addition, fundus photo was taken in all students in the urban school using a non-mydriatic fundus camera. RESULTS: The comparison of blindness, visual impairment, and ocular anomalies were between tribal children (153,107 children; mean age 9.3 ± 2.7 years) examined in the native school and tribal children (10,038 children; mean age 8.8 + 1.64 years) in an urban residential school. Mild and moderate visual impairment was higher in the urban settings (P < 0.05), but severe visual impairment and blindness were similar in both settings. Refractive error, amblyopia, and posterior segment anomaly were detected more often in an urban settings (P < 0.05). Vitamin A deficiency (Bitot's spot) was detected only in children studying in the native schools (P < 0.05). CONCLUSION: The location, urban or rural, did not influence the visual impairment profile of tribal children. The food habit and environment seem to impact nutritional status.