A comparison of autorefraction and subjective refraction with and without cycloplegia in primary school children

PURPOSE: To evaluate the accuracy of autorefraction using three autorefractors comparing to subjective refraction in diagnosing refractive error in children. DESIGN: A cross-sectional study. METHODS: SETTING: Community based study. STUDY POPULATION: 117 children sampled from primary schools. PROCEDURES: All subjects underwent autorefraction using three auto refractors and subjective refraction with and without cycloplegia. MAIN OUTCOME MEASURES: Spherical power, cylindrical power, and spherical equivalence (SE). RESULTS: Without cycloplegia, the mean SE were significantly different for Retinomax K plus 2 (-1.55 diopters, SD 2.37 diopters; 95% CI -1.98 to -1.12; P < .0001) and Canon RF10 (-1.11 diopters; SD 2.61 diopters; 95% CI -1.59 to -0.64; P = .0023) compared with monocular subjective refraction (-0.80 diopters; SD 2.25 diopters; 95% CI -1.21 to -0.35). Mean SE was significantly different for Grand Seiko WR5100K (-0.79 diopters; SD 2.40 diopters; 95% CI -1.23 to -0.35; P = .0002) compared with binocular subjective refraction (-0.62 diopters; SD 2.51 diopters; 95% CI -1.07 to -0.16). With cycloplegia, there was no significant difference in mean SE between refraction methods. Sensitivity and specificity results for the diagnosis of myopia: Without cycloplegia: Retinomax K plus 2 (sensitivity 1.0, specificity 0.51); Canon RF10 (sensitivity 0.92, specificity 0.81); and Grand Seiko WR5100K (sensitivity 0.91, specificity 0.98). With cycloplegia: Retinomax K plus 2 (sensitivity 0.97, specificity 0.99); Canon RF10 (sensitivity 0.97, specificity 0.96); and Grand Seiko WR5100K (sensitivity 1.0, specificity 0.97). CONCLUSIONS: Under noncycloplegic conditions, all three autorefractors have a tendency towards minus over correction in children resulting in over diagnosis of myopia. However autorefractors were accurate under cycloplegic conditions.