Necessity of cycloplegia for assessing refractive error in 12-year-old children: a population-based study.

PURPOSE To compare pre- and postcycloplegic autorefraction in two separate age samples of Australian school children. DESIGN Population-based cross-sectional study of random cluster samples. METHODS Autorefraction was performed before and after cycloplegia, using 1% cyclopentolate, in the right eyes of 2,233 12-year-old and 210 6-year-old children. RESULTS The mean spherical equivalent (SEQ) difference between these measures was 0.84 diopters (D) (95% confidence interval (CI) 0.81 to 0.87 D), more hyperopic in post- than precycloplegic autorefractive assessments in the 12-year-old children and 1.18 D (95% CI 1.05 to 1.30 D) more hyperopic in the 6-year-old children. Precycloplegic autorefraction substantially overestimated the proportion of children with myopia, misclassifying 17.8% aged 12 years and 9.5% aged 6 years. Conversely, precycloplegic autorefraction did not detect moderate to high hyperopia in 2.28% of 12-year-olds and 17.14% of 6-year-olds. CONCLUSIONS Our findings reinforce the importance of using cycloplegic autorefraction in children up to age 12 years.