Prevalence and Causes of Visual Impairment Among Nigerian Children Aged 3 to 5 Years

Abstract

Objectives: This article determines the prevalence and causes of visual impairment (VI) in children aged 3 to 5 years in Ilorin East Local Government Area of Kwara State, Nigeria. Methods: The study was a descriptive, cross-sectional, school-based study of 464 children enrolled by multistage sampling. The sample size was calculated based on the prevalence of ocular morbidity of 19.9% found in a previous Ilorin study by Ayanniyi et al. (Causes and prevalence of ocular morbidity among primary school children in Ilorin, Nigeria. Niger J Clin Pract 2010;13:248-53) using the Fisher’s formula. Visual acuity (VA) of selected children was assessed using the Lea symbols chart. Children meeting the referral criteria of VA worse than 20/30 (6/9.5), two lines difference in VA between the eyes, visible anterior and posterior segment anomalies, and untestable children with the Lea symbols thereafter had a comprehensive eye examination. Results: Seventy (15.1%) of the children screened were 3 years’ old, 176 (37.9%) were 4 years, whereas 218 (47%) were 5 years’ old. Nine hundred twenty-eight eyes of 464 children were screened; 707 (76.2%) eyes in 332 (71.6%) children had VA 6/9.5 or better, whereas 184 (19.8%) eyes in 112 children (24.1%) had VA worse than 6/9.5 and 37 (4%) eyes in 20 children (4.3%) were untestable. An identifiable cause of VI was found in 36 eyes of 23 children, giving a prevalence of 5%. The causes of VI were myopia (2.5%), astigmatism (1.8%), hypermetropia (0.2%), anisometropic amblyopia (0.2%), and strabismus (0.2%). Conclusion: The prevalence of vision impairing conditions in this age group underscores the importance of preschool vision screening to ensure early detection and treatment to prevent the permanent damage of amblyopia.