Prevalence of blindness and visual impairment in Nigeria: the National Blindness and Visual Impairment Study.

Abstract

PURPOSE: To determine the prevalence of blindness and visual impairment among adults aged > or = 40 years in Nigeria. METHODS: Multistage, stratified, cluster random sampling with probability proportional to size procedures was used to identify a cross-sectional nationally representative sample of 15,027 persons > or = 40 years of age from all 36 states in Nigeria and the Federal Capital Territory. Distance visual acuity (VA) was measured with a reduced logMAR tumbling-E chart at 4 and 1 m. Presenting and best corrected visual acuities were recorded. Autorefraction was performed in all examined adults. Clinical evaluations included examination under dilation for those with presenting vision or = 40 years were enumerated and 13,599 (89.9%) examined. Prevalence of blindness ( or = 40 years have moderate to severe visual impairment or blindness ( or = 40 years in Nigeria. Significant differences exist between the geopolitical zones and emphasis should be on ensuring eye services across Nigeria, which means that planning at the regional level is necessary