Pentacam HR及Optovue iVue OCT测量圆锥角膜和近视患者角膜厚度的研究

Study of corneal thickness measurements with Pentacam HR and Optovue iVue OCT in keratoconus and myopic patients

目的分析Pentacam HR、Optovue iVue OCT在圆锥角膜和近视患者中角膜厚度测量值的一致性,以期对角膜交联手术和角膜屈光手术患者角膜厚度测量提供指导。设计诊断技术评价。研究对象2018年10月-2020年10月北京同仁医院圆锥角膜和拟行角膜屈光手术的近视患者181例(359眼),其中近视166眼,圆锥角膜193眼。方法应用Pentacam HR、Optovue iVue OCT测量角膜不同部位厚度及相关参数。采用单因素方差分析或Kruskal-Wallis H检验分析差异性;采用Bland-Altman一致性检验分析两者的一致性;采用Spearman相关分析其与角膜表面形态参数的相关性。主要指标中央角膜厚度、最薄角膜厚度、角膜前表面最大曲率(KMax)、角膜表面变异指数(ISV)、垂直不对称指数(IVA)、高度不对称指数(IHA)、高度偏心指数(IHD)。结果近视组和圆锥角膜组,Optovue iVue OCT测量角膜最薄点、中央厚度均比Pentacam HR平均约低20μm(P均<0.05);两种仪器测量近视组中央区和最薄处的差值跨度均为35μm,而圆锥角膜组中央区和最薄处的差值跨度分别为60μm、84.56μm。两组患者的中央区和最薄点Pentacam HR和Optovue iVue OCT测量角膜厚度差值与KMax、ISV、IVA、IHA、IHD无明显线性相关(近视组中央区:r=0.025,-0.15,-0.165,-0.104,-0.15;其中PIVA=0.034,但散点图显示无线性相关,其余P均>0.05)。结论Optovue iVue OCT测得的角膜厚度值比Pentacam HR约低20μm。对于角膜屈光手术和圆锥角膜交联手术前患者建议参考Optovue iVue OCT的角膜厚度测量值。

Objective To analyze the consistency of Pentacam HR and Optovue iVue OCT in the measurement of corneal thickness in patients with keratoconus and myopia,and to provide guides for the measurement of corneal thickness in keratoconus and myopic patients.Design Diagnostic technique evaluation.Participants 181 cases(359 eyes)of keratoconus and myopia patients scheduled for refractive surgery from October 2018 to October 2020 in Beijing Tongren Hospital.166 eyes were in the myopia group,and 193 eyes were in the keratoconus group.Methods Pentacam HR and Optovue iVue OCT were used to measure the thickness and related parameters of different cornea areas.A one-way analysis of variance or Kruskal-Wallis H test was used to analyze the differences.the Bland-Altman consistency test was used to analyze the consistency.The Spearman correlation coefficient was used to analyze the correlation between the differences and corneal surface morphological parameters.Main Outcome Measures Corneal thickness in central corneal thickness,the thinnest corneal thickness,maximum keratommetry(Kmax),index of surface variance(ISV),index of vertical asymmetry(IVA),index of height asymmetry(IHA),index of height decentration(IHD).Results In the myopia group and keratoconus group,the thinnest point and central thickness of the cornea measured by Optovue iVue OCT was about 20μm lower than Pentacam HR on average,and the difference was statistically significant(all P<0.05).For the central and thinnest thickness in myopia group and keratoconus group,the consistency of the measurement results of the two measuring instruments are quite different.The difference both the central area and the thinnest part in myopia group was about 35μm.The measured difference spans of the central area and the thinnest part in keratoconus group were 60μm and 84.56μm,respectively.Both myopia group and keratoconus group,the corneal thickness difference in the central area and the thinnest point had no obvious linear correlation with KMax,ISV,IVA,IHA,IHD.The central corneal thickness in myopia group:r=0.025,-0.15,-0.165,-0.104,-0.15;PIVA=0.034.However,the scatter plot showed no linear correlation,and the other P values all were>0.05.Conclusions The corneal thickness measured with Optovue iVue OCT is about 20μm lower than with Pentacam HR.It is recommended to refer to the corneal thickness measured with Optovue iVue OCT for patients before refractive surgery and keratoconus cross-linking surgery.