Prevalence And Pattern Of Refractive Errors In Secondary School Students In Lagos State, Nigeria: The Need For A National School Eye Health Screening Programme

Aim: The purpose of this study was to determine the frequency, types and distribution of refractive errors among public secondary students in Lagos State, Nigeria. Methods: This was a descriptive cross -sectional study conducted from October 2005 to January 2007. Randomly selected students in 19 public secondary schools within the 6 education districts in Lagos State constituted the sample. The study in all the schools was preceded by ocular health education. Detailed ocular examination carried out included visual acuity measurements with multiple alphabetical Snellen's chart. Significant refractive error was defined as a visual acuity of 6/12 or worse, or any error correctable with spherical equivalent of at least -0.500DS or +2.00DS, according to the guidelines of Refractive Error Study in Children (RESC) Result: A total of 1,987 students which comprised of 1019 (51.3%) males and 968 (48.7%) females were examined. Their age range was 9-24years, mean age, 14.8 years (95% CI, 12.4-17.2). Using spherical equivalence (SE) of findings, 564 students accounting for 28.4% (95% CI, 26.4 – 30.4) had significant refractive errors. Myopia (SE of at least - 0.50 DS in one or both eyes) accounted for 26.2% (95% CI, 24.2 – 28.2) and hypermetropia, (SE of > + 2.00DS in either eye) constituted 2.2% (95% CI, 1.54 – 2.36). Most of the errors were of low degree and amblyopia was present in 16 participants (0.8%). One hundred and twenty seven students (6.4%) with significant refractive errors however had associated astigmatism. Forty five cases out of these (35.4%) were > 0.75DC. Conclusion: The prevalence rate of 28.4% for refractive errors in the study was higher than previous findings among secondary school  students in Nigeria. Although most students with low degree of myopia were asymptomatic, they are at high risk of further increase due to increasing near work and changes in diet associated with westernization. The need for a sustainable National School Eye HealthScreening Programme cannot be overemphasized. Keywords: Uncorrected Refractive Errors, Amblyopia, Screening, Secondary Schools