Myopia screening: combining visual acuity and noncycloplegic autorefraction.

PURPOSE

To explore the effectiveness of combining uncorrected visual acuity (UCVA) and noncycloplegic autorefraction (NCAR) for large-scale myopia screening in schoolchildren with a high prevalence of myopia.

METHODS

A total of 1687 children aged between 6 and 12 years, from five primary schools in the Baoshan district of Shanghai participated in the study. We measured UCVA and autorefraction before and after cycloplegia by a Topcon KR-8800. We drew receiver operating characteristic curves to achieve the best cutoff points and their corresponding sensitivities and specificities for the UCVA and NCAR, respectively. We then combined the UCVA and NCAR in serial order to explore the optimal criterion and its effectiveness. A specificity of 90% was set to compare the sensitivities among the three tests. The children were divided into three age groups (aged 6 to 7, 8 to 10, 11 to 12 years) to further examine this new method.

RESULTS

A total of 1639 children with an average age of 9.35 (SD, 1.6) years were finally included, among which 428 (26.11%) children were diagnosed as being myopic (spherical equivalent refraction (SER) less than or equal to -0.5 diopters [D]). For the UCVA, the cutoff point is 0.2 logarithm of the minimum angle of resolution (20/32), with a sensitivity and specificity of 63.6% and 94.0%, respectively. For NCAR, the cutoff point is SER less than or equal to -0.75 D, with a sensitivity and specificity of 88.6% and 86.1%, respectively. When UCVA is combined with NCAR, the best cutoff point is UCVA less than or equal to 0 logarithm of the minimum angle of resolution (20/20) and SER less than or equal to -0.75 D, with a sensitivity and specificity of 84.4% and 90.5%, respectively. At a specificity of 90%, the sensitivities are 63.55%, 78.50%, and 84.35%, respectively, for UCVA, NCAR, and the combination test. In all age groups, the combination test had the highest sensitivities among the three tests.

CONCLUSIONS

In a population with a high prevalence of myopia, combining the UCVA and NCAR in serial order achieved higher sensitivity than either of the two tests alone, when specificity was set at 90%.