三种仪器测量中央角膜厚度的对比研究

Comparison of central corneal thickness measurements using three different instruments

目的探讨Pentacam眼前段分析仪、Orbscan-Ⅱ眼前节分析仪与A超角膜厚度测量仪三种仪器测量中央角膜厚度的差异。方法126例(252眼)欲做准分子激光手术的近视患者分别用Pentacam眼前段分析仪、A超角膜测厚仪、Orbscan-Ⅱ三种仪器测量中央角膜厚度。用SPSS11.0统计学软件对不同方法测量的结果进行配对t检验,并作Pearson相关性分析。结果三种仪器所测得中央角膜厚度测量结果分别为:Pentacam(546.3±33.6)μm,Orbscan-Ⅱ(550.5±38.5)μm,A超角膜测厚仪(538.6±35.4)μm。三种检查仪测量结果两两之间差异均有统计学意义(P=0.000),且有高度的相关性。A超角膜测厚仪比其他两种测量仪测量所得的中央角膜厚度要薄。再以A超角膜测厚仪测量的角膜厚度为基准把患者分为三组:<520μm,≥520μm且<580μm,≥580μm,对三种仪器测量的结果进一步对比分析。第一组角膜厚度<520μm,71只眼,A超角膜测厚仪测量结果比Pantacam和Orbscan-Ⅱ测量结果要薄,差异均有统计学意义(P=0.000,P=0.000)。而Pentacam与Orbscan-Ⅱ的测量值差异无统计学意义(P=0.143)。第二组角膜厚度≥520μm且<580μm,154只眼,Orbscan-Ⅱ测量结果比Pantacam较厚,Pantacam比A超角膜测厚仪测量结果要厚,差异均有统计学意义(P=0.000,P=0.000)。第三组角膜厚度≥580μm,27只眼,Orbscan-Ⅱ测量结果比Pantacam和A超角膜测厚仪测量结果要厚,差异均有统计学意义(P=0.000,P=0.000),而Pentacam与A超角膜测厚仪的测量值差异无统计学意义(P=0.747)。结论在对中央角膜厚度的测量中,Pentacam、Orbscan-Ⅱ与A超角膜测厚仪三种仪器之间是不能互相替换的。

Objective To compare the difference in central corneal thickness（CCT） measurements using a Pentacam,an Orb-scan-Ⅱ topography system and A-scan ultrasound pachymetry.Methods The CCTs of 252 healthy eyes（from 126 myopic subjects） were measured with a Pentacam,Orbscan-Ⅱ and A-scan ultrasound pachymetry.The differences between the instruments were evaluated with paired t-tests.The correlation between the measurements was evaluated using Pearson correlation coefficients.Results Of the 252 eyes,the CCT values obtained with the Pentacam,Orbscan-Ⅱ and A-scan ultrasound pachymetry were（546.3±33.6） μm,（550.5±38.5）μm and（538.6±35.4）μm,respectively.There was a high correlation among them.The CCT values obtained with A-scan ultrasound pachymetry were the lowest among the three mea-surements.This sample（252 eyes） was divided into 3 groups according to the CCT measurements obtained with A-scan ultrasound pachymetry.In group 1,71 eyes had CCT values less than 520 μm.The CCT values with A-scan ultrasond pachymetry were thin-ner than those obtained with a Pentacam or A-scan ultrasound pachymetry.The differences were significant（P =0.000,P =0.001）.There were no statistically significant differences between Orbscan-Ⅱ and Pentacam measurements.In group 2,154 eyes had CCT values from 520 μm to 580 μm.The CCT values obtained with an Orbscan-Ⅱ were thicker than those obtained with a Pentacam and the CCT values with a Pentacam were thicker than those ob-tained with an A-scan ultrasound pachymetry.The differences were significant（P=0.000,P=0.000）.In group 3,27 eyes had CCT values of more than 580 μm.The CCT values with Orbscan-Ⅱ were thicker than those obtained with a Pentacam or A-scan ultrasound pachymetry.The differences were significant（P=0.000,P=0.000）.There were no statistically significant differences between A-scan ultrasound pachymetry and Pentacam.Conclusion Pentacam,Orbscan-Ⅱ and A-scan ultrasound pachymetry cannot be used interchangeably when measuring central corneal thickness.