Refractive errors in children with down syndrome in Lagos State, Nigeria
Down syndrome is the most common chromosomal disorder and many with the condition tend to be more at risk of several ocular disorders than those without Down syndrome. The study was aimed at assessing the distribution of refractive errors in children with Down syndrome between 5-18 years of age. The cross-sectional study used data from 104 children with Down syndrome from selected exclusive special needs schools in Lagos State, Nigeria. Visual acuity was measured using the Lea symbol chart and non-cycloplegic refraction was carried out using both static retinoscopy and autorefraction. Significant refractive error was defined as myopia, hyperopia and astigmatism of 0.75D and above respectively. Data was analysed using IBM SPSS statistical software version 20.1. Chi-square and independent t test were used to test the hypotheses. A total of 91 children with Down syndrome were examined; 52 (57.1%) were males with a mean age of 13.6 +3.8 years. The study showed that refractive errors was present in 82 (95.3%) of the participants, with astigmatism being the commonest form of refractive error occurring in 61(67%) followed by hyperopia 12(13.2%) and myopia 7(7.7%) of the 91 participants studied. The study also supported the null hypothesis that there is no significant difference between the types of refractive error and gender (p=0.8331). Recorded visual acuities also revealed a generalised reduced visual acuity which significantly improved with best optical correction (p <0.001). This study indicates the need for people with Down syndrome to be provided with prompt eye care services.
Keywords: Refractive error, Down syndrome, visual acuity, prevalence, distribution