Accuracy of Noncycloplegic Autorefraction in School‐Age Children in China

Purpose. To evaluate the accuracy of noncycloplegic autorefraction in a representative sample of school‐age children in China. Methods. Refractive error was measured with an autorefractor, both before and after cycloplegia induced with cyclopentolate, in a population‐based sample of 4973 children between the ages of 7 and 18 years. Spherical equivalent refractive error and astigmatism as represented by Jackson crossed‐cylinders (J 0 and J 45 ) were the main outcome measures. Results. Noncycloplegic measurements of equivalent spheres were consistently more negative or less positive than those after cycloplegia, with mean ± SD differences of −1.23 ± 0.97 D. The differences were particularly large for hyperopic eyes (mean difference of −2.98 ± 1.65 D for hyperopia of at least +2.00 D) while becoming progressively smaller for emmetropic eyes, and smaller yet for myopic eyes (mean difference of −0.41 ± 0.46 D for myopia of −2.00 D or more). Increasing age was associated with increased, but clinically insignificant, differences. Little difference was found between noncycloplegic and cycloplegic measurements of astigmatism: mean J 0 and J 45 differences were −0.08 ± 0.13 D and −0.01 ± 0.09 D, respectively. Conclusions. Noncycloplegic autorefraction was found to be highly inaccurate in school‐age children and, thus, not suitable for studies of refractive error or for prescription of glasses in this population.