The Prevalence of Hypermetropia and Myopia in a Large Unselected, Multicultural Population of School Children in Eastern Sydney

Abstract

Abstract: : Purpose:To determine the prevalence of myopia and hyperopia in an unselected population of young urban school children in Sydney, and relate this to possible changes in prevalence over the last two decades. Methods:Refractive data from retinoscopy without cycloplegia was reviewed for 3590 children aged 4 to 12 who underwent a functional vision screening when visiting the Vision Education Centre at UNSW as part of an excursion to the university in either the early 1990’s or early 2000’s. Myopia was defined as right eye spherical equivalent greater than -0.50 D, and hypermetropia was defined as greater than +0.50 D. Results:The children came from over 20 schools, and were from a wide range of socio and ethnic backgrounds. Approximately 39% were born overseas according to local census data, 57% from wider Europe and 22% from Asia. For the 2584 children seen in the early 90’s, the mean spherical equivalent was 0.50±0.82D, 3.9% were myopic and 38.5% were hyperopic. In the early 2000’s the mean error was 0.34±1.13D and the prevalences were 8.3% and 36.5% respectively. A 3-way ANOVA for decade, age and gender showed no significant main effect for decade or gender, but significant interaction between the three variables. There was a myopic shift with increasing age (p<0.0001) in both decades, and a trend towards more myopia in recent years. Conclusions:This data from a large unselected population is similar to published data gathered by us in Melbourne from a non-clinical population of children in the early 1980’s (mean spherical equivalent of 0.39±0.95, N=1,023). Other data from three studies of over 8,000 non-clinical rural and urban children around Sydney and Melbourne, published in the 1970s and 1980s, yielded similar findings. We conclude that the prevalence of myopia in Australian children is significantly lower than that in Asia and the US, and is not demonstrating the rapid increase observed in other countries. Is this a question of lifestyle?

Keywords: myopia • hyperopia • clinical (human) or epidemiologic studies: pre