Low Vision Among Students Attending Schools for Blind Students in Two States of North-Central Nigeria

Abstract

Introduction: Surveys conducted in schools for blind students have become useful alternatives to population-based surveys in generating data on childhood blindness and low vision. This survey determined the prevalence of low vision, causes of visual impairment, and the proportion of students requiring low vision devices and provided the low vision devices required. Methods: The study was conducted in three schools for blind students in two states of north-central Nigeria. The standard examination protocol of the World Health Organization’s Prevention of Blindness and Low Vision for Children (WHO, 2005) was used to interview and assess participants. The causes of visual impairment were categorized using the definitions in the coding instruments (WHO, 1988). Results: The study examined 170 eyes of 85 students between 7 and 49 years of age with a male-to-female ratio of 1.4:1. Of the 83 (97.6%) students with visual impairments, 59 (69.4%) of them had low vision. The major anatomical sites of vision loss by eyes were the whole globe (n = 84, 55.3%), followed by the lens (n = 23, 15.1%) and the retina (n = 21, 13.8%). Overall, the leading causes of visual impairment in eyes were glaucoma (n = 52, 34.2%), retinitis pigmentosa (n = 21, 13.8%), phthisis bulbi (n = 16, 10.5%), cataract (n = 14, 9.2%), and keratoconus (n = 10, 6.6%). A total of 37 (43.5%) students were prescribed optical low vision devices, and 28 (32.9%) received nonoptical low vision devices. Discussion: A large number of the students in this study had low vision. They were prescribed and provided the low vision devices required. The causes of visual impairment were a mix of the patterns seen in both developing and developed countries. The finding of glaucoma as a more important cause of vision loss calls for improved efforts in screening, early detection, and treatment of glaucoma among children. Implications for Practitioners: Routine comprehensive visual assessment, refraction, and low vision assessment before enrollment will guard against improper school placements and enhance optimization of vision for those with low vision.