Orbscan—II、Pentacam及超声测厚仪角膜厚度测量值的比较

目的探讨Orbscan-II、Pentacam及超声角膜测厚仪三种仪器测量角膜中央厚度的差异及其临床意义。方法对预行准分子激光角膜手术的近视患者159例（318眼），采用0rbscan—II、Pentacam及超声角膜测厚仪三种仪器测量角膜中央厚度，并对测量结果进行统计学分析。再根据超声角膜测厚仪所测得的角膜厚度进一步将患者分为三组（〈500um组、500～570um组和≥570um组），在每个组中对三种方法所测得的结果进行统计学分析。结果Orbscan-II、Pentacam、超声角膜测厚仪测得的角膜中央厚度平均值分别为（527．9±43．0）um、（526．3±38．4）um、（522．6±37．8）um。经方差分析，三者差异无统计学意义（F=1．491，P=0．226）。分组后，角膜厚度〈500um和500—570um组，三种方法所得数据差异无统计学意义（F=1．546，P=0．215；F=2．107，P=0．123）；而≥570um组，三种方法测量结果差异存在统计学意义（F=5．396，P=0．006），进一步采用Bonferroni检验分析组间差异，Orbcan—II组测量值明显高于Pentacam组（P=0．029）和超声测厚仪组（P=0．010），Pentacam组和超声测厚仪组之间无差异（P〉0．05）。结论三种方法用于测量准分子激光角膜手术前近视患者的角膜中央厚度时虽然存在一定差异，但总体上无统计学意义，具有很好的协同性，但相互间还不能完全替代。

Comparison of central corneal thickness measured with Orbscan-Ⅱ, Pentacam and ultrasonic pachymetry

Objective To assess the reliability of Orbscan-Ⅱ , Pentacam and ultrasonic pachymetry (US) for central corneal thickness (CCT) measurements. Methods Central corneal thick- ness was measured using Orbscan-Ⅱ, Pentacam and ultrasonic pachymetry in 159 preoperative cases (318 eyes). Patients were further divided into three groups according to corneal thickness (<500 μm group, 500～570 μm group and ≥570 μm group) as determined by ultrasonic pachymetry and the differences in the measurements obtained by all three methods were statistically analyzed for the three groups. Results The mean CCT readings with Orbscan-Ⅱ, Pentacam, and ultrasonic pachymetry were (527.9±43.0)μm, (526.3±38.4)μm, and (522.6±37.8)μm, respectively. No statistically significance differences were found among the three instruments (F=1.491, P=0.226) using analysis of variance. After the patients were divided into three groups based on the ultrasonic pachymetry measurements, the results showed that there was no statistically significant difference in measurements by the three instruments for the <500 μm group and the 500～570 μm group (F=1.546, P=0.215;F=2.107, P= 0.123), while there was a significant difference for the ≥570 μm group (F=5.396, P=0.006). Differ-ences among the groups using Bonferroni tests show that central corneal thickness (CCT) measured with Orbcan-Ⅱ was significantly thicker than that obtained with the Pentacam (P=0.029) and ultra-sonic pachymetry (P=0.010). No statistically significant difference was found between measurements with Pentacam and ultrasonic pachymetry. Conclusion There are some differences in the three meth-ods used to measure the CCT of patients before excimer laser myopic surgery, but overall there was no statistically significant difference, and the methods could be concordant in clinics. However, the three instruments still cannot completely replace one other.