Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量近视患者角膜前表面曲率的重复性和一致性分析

Comparison of keratometry consistency between Pentacam and Keratron Scout topography among myopic patients

目的探讨以Schiempflug原理设计的Pentacam眼前节分析仪和以Placido盘为基础的Keratron Scout角膜地形图仪测量角膜前表面曲率的重复性,并分析两种仪器测量结果的一致性。方法随机数字表法随机选取于2018年1月1~30日在我院眼视光中心行角膜激光近视矫正术前检查的69例患者,所有受试者由同一检查者分别采用Pentacam眼前节分析仪和Keratron Scout角膜地形图仪重复测量3次,两种仪器测量顺序随机,记录患者平坦轴角膜曲率(Kf)、陡峭轴角膜曲率(Ks)和平均角膜曲率(Km),采用变异系数(CV%)、组内相关系数(ICC)(95%CI)和Cronbach’s Alpha系数评价两种仪器测量结果的可重复性,t检验比较两种仪器测量结果的差异,Pearson相关分析法分析其相关性;Bland-Altman图分析一致性界限范围。结果3次重复测量时,Pentacam眼前节分析仪测量Kf的CV为0.39%,ICC(95CI%)为0.811(0.651~0.907),Cronbach’s Alpha系数为0.935,Ks的CV为0.28%,ICC为0.975(0.959~0.985),Cronbach’s Alpha系数为0.991,Km的CV为0.25%,ICC为0.944(0.911~0.967),Cronbach’s Alpha系数为0.981;Keratron Scout角膜地形图仪测量Kf的CV为0.43%,ICC为0.820(0.678~0.951),Cronbach’s Alpha系数为0.967,Ks的CV为0.47%,ICC为0.937(0.908~0.959),Cronbach’s Alpha系数为0.978,Km的CV为0.39%,ICC为0.937(0.907~0.958),Cronbach’s Alpha系数为0.978。Pentacam眼前节分析仪和Keratron Scout角膜地形图仪测量Kf、Ks和Km的结果差异无统计学意义(Kf:P=0.187;Ks:P=0.721;Km:P=0.169),两种仪器测得结果有相关性(Kf:r=0.622,P=0.000;Ks:r=0.980,P=0.000;Km:r=0.983,P=0.000),Kf的95%Lo Al为-0.43~0.40D,Ks的95%Lo Al为-0.56~0.59 D,Km的95%LoAl-0.46~0.39 D。结论以Schiempflug原理设计的Pentacam眼前节分析仪和以Placido盘为基础的Keratron Scout角膜地形图仪测量角膜屈光手术患者角膜前表面曲率均具有良好的可重复性,两种仪器测量得角膜前表面曲率结果准确,一致性好,可以相互验证。

Objective To evaluate the consistency of keratometry measurement by Pentacam Front Section Analyzer(schiempflug image)and Keratron Scout Corneal Topography(Placido disc)and analyze the repeatability of each instrument.Methods Sixty nine patients who underwent corneal refractive surgery from January 1 st to 30 th at the ophthalmology department of Leshan people’s hospital were randomly selected using random number table method preoperatively.All patients were examined by the same doctor using pentacam and keratron scout corneal topography respectively.Three consecutive measurements were taken using each instrument for repeatability analysis,and the sequence of measurement by these two instruments were also random.The flat keratometry(Kf),steep keratometry(Ks)and mean keratometry(Km)were recorded and compared using coefficient of variation,intraclass correlation coefficient(ICC),and Cronbach’s Alpha Coefficient.T test was used to assess the difference in the measurements by these two instruments,Pearson correlation analysis was used for correlation analysis and Bland-Aaltman analysis was used for consistency analysis.Results Both instruments showed good intra-group repeatability with low coefficient of variation,high ICC and Cronbach’s Alpha coefficient.Pearson correlation analysis showed significant correlations between the results(Kf r=0.622,P=0.000;Ks:r=0.980,P=0.000;Km:r=0.983,P=0.000).No significant difference was found between Kf,Ks and Km measured by these two instruments.95%Lo Al of the two instruments was-0.43 to 0.40 D,-0.56 to 0.59 D and-0.46 to 0.39 D for Kf,Ks and Km by Bland-altman analysis method,respectively.Conclusions Pentacam Front Section Analyzer(Schiempflug)and Keratron Scout corneal topography(Placido disc)showed good repeatability and consistency in determining Kf,Ks and Km of the anterior corneal curvature in myopic patients preoperatively.The two instruments could be used for mutual corroboration.