目的 分析VERION数字导航系统测量角膜曲率和散光的可重复性及其与iTrace、Lenstar LS900、手动角膜曲率计检测结果的一致性.方法 对62名年龄相关性白内障患者分别用上述四种仪器进行角膜生物测量,记录并分析陡峭轴角膜曲率(steep keratometry,Ks)、平坦轴角膜曲率(flat keratometry,Kf)、散光幅度、散光轴位、矢量参数J0和J45.分析VERION测量的可重复性,并比较VERION与其他三种仪器测量结果的一致性.结果 用组内相关系数(intraclass correlation coefficient,ICC)和克隆巴赫系数(Cronbach's alpha,α)分别对Ks、Kf、散光幅度、散光轴位、J0以及J45做出分析,结果均大于0.9(均为P＜0.001),提示VERION测量角膜曲率及散光的可重复性极好.VERION测量的Ks、散光幅度均高于iTrace(均为P＜0.05),其余指标的差异无统计学意义(均为P＞0.05).Bland-Altman分析显示J0、J45及散光轴位的95％ LOA分别为(-0.31 ～0.35)D、(-0.25～0.31)D、-13.5°～12.3°.二者测量的散光轴位差小于10°者占总体的77％ (48/62),在合并角膜散光大于1D的患者中占91％ (42/46).VERION与Lenstar LS900测量结果仅J45差异有统计学意义(P＜0.05),其余指标差异无统计学意义(均为P＞0.05).Bland-Altman分析发现J0、J45及散光轴位的95％ LOA分别为(-0.25 ～0.31)D、(-0.27 ～0.36)D、-13.5°～11.0°.二者测量的散光轴位差小于10°者占总体的85％(53/62),在合并角膜散光大于1D的患者中占93％(43/46).VERION与手动角膜曲率计检测的Kf、散光幅度差异有统计学意义(均为P＜0.05),其余指标差异无统计学意义(均为P＞0.05).Bland-Altman分析显示J0、J45及散光轴位的95％ LOA分别为(-0.38 ～0.35)D、(-0.41 ～0.42)D、-12.6° ～16.4°.二者测量的散光轴位差小于10°者占总体的81％ (50/62),在合并角膜散光大于1D的患者中占91％(42/46).结论 VERION在测量角膜曲率及散光方面具有良好的可重复性.其与iTrace、Lenstar LS900和手动角膜曲率计在角膜曲率、散光幅度的测量方面一致性较好,但对散光轴位的测量差别较大.%Objective To analyze the reproducibility of keratometry and astigmatism measured by the VERION Digital Guidance System and the comparability of VERION with iTrace,Lenstar LS900 and manual keratometer.Methods The keratometry of 62 cataract patients were measured using four different devices.The steep keratometry (Ks),flat keratometry (Kf),astigmatic magnitude,astigmatic axis,cylinder at 0-degree meridian (vector component,J0) and cylinder at 45-degree meridian (vector component,J45) from each machine were recorded and analyzed.The three repeated measurements and the results of VERION system with other three devices were compared to analyze the reproducibility and comparability of VERION system.Results Reproducibility:Intraclass correlation coefficients and Cronbach's alpha values were higher than 0.9 for Ks,Kf,astigmatic magnitude,astigmatic axis,J0 and J45 measured by the VERION system (all P ＜ 0.001).Comparability:The results of Ks and magnitude of astigmatism of VERION were larger than the iTrace (all P ＜ 0.05) in the paired-samples t test.There was no statistical difference for the rest of parameters (all P ＞ 0.05).The Bland-Altman graphs revealed the 95％ limits of agreement (LOA) of J0,J45 and the astigmatic axis between VERION and iTrace were (-0.31-0.35) D,(-0.25-0.31) D and-13.5 °-12.3 °,respectively;There was no statistical differences for all parameters except for J45 in the paired-samples t test between the VERION and Lenstar LS900 (all P ＞ 0.05).The Bland-Altman graphs revealed the 95％ LOA of J0,J45 and the astigmatic axis were (-0.25-0.31)D,(-0.27-0.36) D and-13.5°-11.0°,respectively;There were statistical differences for the results of Kf and magnitude of astigmatism between the VERION and manual keratometer (all P ＜ 0.05).The Bland-Altman graphs revealed the 95％ LOA of J0,J45 and the astigmatic axis between VERION and manual keratometer were (-0.38-0.35) D,(-0.41-0.42) D,-12.6°-16.4°,respectively.Conclusion The VERION system is a reliable system for the measurement of keratometry and astigmatism.The keratometry and astigmatic magnitude of the VERION system have a good agreement with the iTrace,Lenstar LS900 and manual keratometer.However,the astigmatic axis measurements are significantly different among the four devices.
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