Low Vision among students attending schools for the Blind in two states of North-Central Nigeria

Abstract

Background: Surveys conducted in schools for the blind have become useful alternatives to population-based surveys in generating data on childhood blindness and Low Vision (LV). It has been observed that some of the students in blind schools are partially sighted, retaining a degree of usable residual vision known as LV that could be enhanced with Low Vision Aids (LVA). This study determined the prevalence of LV, causes of vision loss, the proportion of students who will benefit from LVA and to provide the LVA required. Methodology: The study was conducted in three schools for the blind in two states of north-central Nigeria. The standard examination protocol of the World Health Organization (WHO) Prevention of Blindness and LV for Children was used to interview and assess participants. The causes of vision loss were categorized using the definitions in the coding instruments. Results: The study enrolled and examined 170 eyes of 85 students aged between 7 and 49 years of age with a male-to-female ratio of 1.4:1. A total of 83 (97.6%) students were visually impaired, and 59 (69.4%) had LV. The major anatomical sites of vision loss by eyes were the whole globe (84,55.3%), followed by the lens (23,15.1%) and the retina (21,13.8%). Overall, the leading causes of vision loss were glaucoma (52,34.2%), retinitis pigmentosa (21,13.8%), phthisis bulbi (16,10.5%), cataract (14,9.2%) and keratoconus (10,6.6%). Aetiology was suspected to be hereditary in (35,42.2%) eyes and indeterminate in the rest. Avoidable causes of vision loss were all treatable and accounted for (79,52.0%) of all cases. A total of (37,43.5%) students benefitted from optical LVA and (28,32.9%) received non-optical LVA. Conclusion: Majority of the students attending schools for the blind in Plateau and Nasarawa states at the time of the study were partially sighted, mainly from treatable causes. A third of them benefitted from the LVA provided. Keywords: Low vision, blind, school, Nigeria Key message: Some students attending schools for the blind may be partially sighted and can benefit from LVA. Pre-enrollment LV assessment will help mitigate erroneous school placements while periodic LV assessment will enhance identification of those whose vision can be maximized with LVA.