Purpose: To compare 3 automated devices for measuring the horizontal corneal diameter [white-to-white (WTW) distance]. Methods: In 65 eyes of 38 patients, the WTW distance was measured independently using Orbscan IIz tomography system (Bausch & Lomb), IOLMaster 700 (Carl Zeiss Meditec) and OPD Scan III (NIDEK). We tested for systematic differences in measurements and estimated the limits of agreement (LoA) using linear mixed effects models. Results The mean WTW distance was 11.8 0.40 mm with Orbscan IIz, 12.1 0.5 mm with IOLMaster 700 and 12.0 0.4 mm with OPD Scan III. The mean difference between IOLMaster 700 and Orbscan IIz was 0.33 (95% CI 0.28;0.38) (p<0.001), between OPD Scan III and Orbscan IIz was 0.24 mm (95% CI 0.21;0.28) (p<0.001), and between IOL Master 700 and OPD Scan III was 0.09 (95% CI 0.05;0.12) (p<0.001). The 95% LoA for Orbscan IIz versus IOLMaster 700 was -0.69 mm to 0.03 mm, Orbscan IIz versus OPD Scan III was -0.52 mm to -0.03 mm, and OPD versus IOLMaster 700 was -0.39 mm to 0.22 mm. Switching to IOLMaster 700 or OPD Scan III measurements led to a selection of a longer phakic IOL length (Visian ICL, STAAR) in 34% and 33% of the cases, respectively compared to Orbscan IIz. Conclusions: The data suggests that these devices are not interchangeable for usual clinical practice. Adjustments based on mean differences was not enough to compensate for inter-instrument discrepancy in WTW measurements.

中文翻译：

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使用Orbscan IIz，OPD Scan III和IOLMaster 700进行水平角膜直径测量的比较

目的：比较3种用于测量水平角膜直径[白到白（WTW）距离]的自动化设备。方法：在38例患者的65眼中，使用Orbscan IIz断层扫描系统（Bausch＆Lomb），IOLMaster 700（卡尔·蔡司Meditec）和OPD Scan III（NIDEK）独立测量WTW距离。我们测试了测量中的系统差异，并使用线性混合效应模型估算了协议限制（LoA）。结果Orbscan IIz的平均WTW距离为11.8 0.40 mm，IOLMaster 700的平均WTW距离为12.1 0.5 mm，OPD Scan III的平均WTW距离为12.0 0.4 mm。IOLMaster 700和Orbscan IIz之间的平均差异为0.33（95％CI 0.28; 0.38）（p <0.001），OPD Scan III和Orbscan IIz之间的平均差异为0.24 mm（95％CI 0.21; 0.28）（p <0.001），并且IOL Master 700和OPD Scan III之间的差值为0.09（95％CI 0.05; 0.12）（p <0.001）。Orbscan IIz与IOLMaster 700的95％LoA为-0.69 mm至0.03 mm，Orbscan IIz与OPD Scan III的-0.52 mm至-0.03 mm，OPD与IOLMaster 700的OPD为-0.39 mm至0.22 mm。与Orbscan IIz相比，分别切换到IOLMaster 700或OPD Scan III测量导致分别在34％和33％的情况下选择了更长的晶状体IOL长度（Visian ICL，STAAR）。结论：数据表明这些设备在常规临床实践中是不可互换的。基于均值差的调整不足以补偿WTW测量中的仪器间差异。与Orbscan IIz相比，分别切换到IOLMaster 700或OPD Scan III测量导致分别在34％和33％的情况下选择了更长的晶状体IOL长度（Visian ICL，STAAR）。结论：数据表明这些设备在常规临床实践中是不可互换的。基于均值差的调整不足以补偿WTW测量中的仪器间差异。与Orbscan IIz相比，分别切换到IOLMaster 700或OPD Scan III测量导致分别在34％和33％的情况下选择了更长的晶状体IOL长度（Visian ICL，STAAR）。结论：数据表明这些设备在常规临床实践中是不可互换的。基于均值差的调整不足以补偿WTW测量中的仪器间差异。