Abstract
AIM: To compare the subjective refraction data with auto-refraction findings in high astigmatisms. METHODS: In a cross-sectional study, sampling was done from in different geographic regions in Iran using a multistage random cluster sampling method. All study participants underwent cycloplegic auto-refraction and subjective refraction using the red-green test. RESULTS: In this study, 277 eyes of 158 students aged 8 to 15y were analyzed. According to the results, the mean difference between subjective refraction and autorefraction in measuring sphere, cylinder, spherical equivalent, J0, and J45 was -0.18±0.76, -0.36±0.40, -0.36±0.79, 0.15±0.20, and 0.05±0.21 respectively. The correlation of these two refraction methods in measuring the aforementioned indices was 0.963, 0.898, 0.960, 0.931, and 0.948 respectively. The 95% limits of agreement of the two methods in measuring the above indices were -1.66 to 1.31, -1.14 to 0.42, -1.91 to 1.19, -0.24 to 0.54, and -0.36 to 0.47 respectively. The agreement between the two methods decreased with increasing cylinder power, and the best agreement was found in myopic individuals. CONCLUSION: The measurements obtained by autorefractometer have a significantly higher cylinder average compared to subjective refraction. However, in the cylinder range of 4-5 diopters, the values of J0 and J45 do not have a high correlation.