AIM: To assess the consistency of refractive errors measured by two autorefractors in myopia screening of school-age Chinese children.

METHODS: Topcon RM-8900 and Tianle RM-9000 autorefractors were utilized to measure refractive errors under noncycloplegic condition in students aged 6 to 16 years old who were cluster sampled from four primary and secondary schools in Dongli district, Tianjin. Sperman correlation analysis and Bland-Altman method were used to evaluate the consistency of spherical diopters, cylindrical diopters and spherical equivalents measured by the two methods, and the axial difference distribution of astigmatism measured by the two methods was analyzed.

RESULTS:A total of 2 276 eyes of 1 138 subjects with a mean age of 10.49±2.66 a were finally enrolled. Spearman correlation analysis showed that sphere(r=0.958, P<0.0001), cylinder(r=0.769, P<0.0001), and spherical equivalent(r=0.962, P<0.0001)measured by Tianle RM-9000 were highly correlated with those measured by Topcon RM-8900, respectively. Bland-Altman analysis showed spherical diopters measured by Tianle RM-9000 were significantly more hyperopic(P<0.0001)with a mean difference of 0.44 D(SD: 0.37; 95% CI: -0.27, 1.16)while the maximum absolute value(1.13 D)of the difference within the 95% CI was above the clinically acceptable range; however, no significant difference(P=0.83)was found between cylindrical diopters measured by the two methods with a mean difference of -0.01 D(SD: 0.31; 95% CI=-0.62, 0.61)while the maximum absolute value(0.62 D)of the difference within the 95% CI was clinically acceptable. The proportion of the axial deviation within ±20° was 84.6%(1 503/1 777)in eyes with cylinder ≤-0.25D while that rose to 96.4%(853/885)in eyes with cylinder ≤-0.75D.

CONCLUSION: Spherical diopters measured by Tianle RM-9000 have a significant hyperopia bias than those measured by Topcon RM-8900 while the consistency of cylindrical diopters and cylindrical axes is clinically acceptable.