AIM: To evaluate the repeatability of axial length(AL)and anterior chamber depth(ACD)obtained by A scan ultrasonography, and to compare AL and ACD obtained by A scan with those obtained by IOL Master.

METHODS: Two hundred and fifty-seven cataract eyes of 170 patients were included. IOL Master and A scan were performed for each eye. Five measurements of IOL Master and 3 measurements of A scan were obtained. All the tested eyes were divided into 5 groups according to AL obtained by A scan: Group A(2129mm, 21 eyes). Cronbach's Alpha coefficient and intraclass correlation coefficient(ICC)were applied to evaluate the repeatability of AL and ACD obtained by A scan. Paired t test and Pearson correlation coefficient were used to analyze the differences and correlations of AL and ACD obtained by the 2 devices, respectively. Bland-Altman plots were presented to analyze the agreements of AL and ACD obtained by the 2 devices.

RESULTS: All the Cronbach's Alpha and ICCs of AL and ACD values were more than 0.98. The differences of AL values between A scan and IOL Master were -0.11±0.08mm in Group A, -0.15±0.10mm in Group B, -0.19±0.15 mm in Group C, -0.29±0.16mm in Group D and -0.45±0.29mm in Group E, respectively(all P<0.01). The differences of ACD values between A scan and IOL Master were -0.10±0.16mm in Group A, -0.06±0.13mm in Group B, -0.06±0.13mm in Group C, -0.19±0.10mm in Group D, -0.18±0.21mm in Group E, respectively(all P<0.01). In all groups, the AL and ACD values obtained by A scan and IOL Master presented good correlations(all r>0.89, all P<0.01).

CONCLUSION: The AL and ACD values in cataract eyes obtained by A scan were repeatable. The AL and ACD values obtained by A scan were smaller than those obtained by IOL Master. With the increase of AL values, the differences of AL values between A scan and IOL Master increased.