Prevalence of astigmatism in Hangzhou children aged 6-15

Objective To exam the prevalence of astigmatism in Hangzhou children aged 6-15,and to explore the distribution rule and main type.Methods A cluster sampling method was used to select 5 elementary schools and 2 junior high schools in Hangzhou.Noncycloplegic autorefraction was conducted on the right and left eye of each children.Results A total of 6 643 students were examined.Defining astigmatism as worse than or equal to 0.50D,0.75D,and 1.00D cylinder in one eye,the prevalence of astigmatism was 72.39%(4 809),32.74%(2 175),and 17.66%(1 773).The rate of astigmatism increased with grades,which had a significant difference(P0.01),and there was a significant increase at 10-years-old.But no different between genders(P0.05).The low astigmatism were the main groups accounting for 90.39%.And the distribution of degree among each age group had no significant difference(χ2=29.062,P=0.358).With-the-rule astigmatism was most common(82.87%) than against-the-rule astigmatism,and the majority of astigmatism was compound myopia astigmatism(77.83%).The rate of with-the-rule astigmatism increased with degree.In contrast,the rate of against-the-rule astigmatism decreased with degree.In addition,the rate of mixed astigmatism increased and compound myopia astigmatism decreased with degree.Conclusion The prevalence of astigmatism is high.In Hangzhou,most astigmatism is myopic with-the-rule astigmatism.The higher degree of astigmatism,the more with-the-rule.The screening and correcting as early in children need to be improved.