方法：选取白内障患者170例257眼，术前分别行IOL Master和A超检查，其中每只受试眼IOL Master自动测量5次，A超测量3次，分别取平均值。按A超测得的AL分为5组：A组：2129mm(21眼)。Cronbach's Alpha系数及组内相关系数(ICC)评估A超测量AL和ACD的可重复性。配对样本t检验和Pearson相关系数分析各组中A超和IOL Master测量的AL和ACD的差异性和相关性。Bland-Altman分析A超和IOL Master测量的AL和ACD的一致性。

结果：A超测量的AL和ACD的Cronbach's Alpha系数和ICC均大于0.98。A、B、C、D、E组中， A超测量的AL与IOL Master测量的AL差值分别为-0.11±0.08、-0.15±0.10、-0.19±0.15、-0.29±0.16、-0.45±0.29mm，差异均有统计学意义(均P<0.01)； ACD差值分别为-0.10±0.16、-0.06±0.13、-0.06±0.13、-0.19±0.10、-0.18±0.21mm，差异均有统计学意义(均P<0.01)。A、B、C、D、E组中，A超和IOL Master测量的AL和ACD均具有很好的相关性(均r >0.89，P<0.01)。

结论：A超测量白内障患者的AL和ACD具有很好的可重复性，且数值均比IOL Master小； 其中不同眼轴长度的差异，随着眼轴的增长而增大。

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.