近视眼角膜生物力学特性与角膜高阶像差的相关性

Correlation analysis between corneal biomechanical properties and high-order aberration in myopia

目的探讨近视患者角膜生物力学特性与角膜高阶像差（HOAs）的相关性。方法采用回顾性病例观察研究。收集2015年1—10月在天津市眼科医院屈光手术中心就诊的近视及近视散光患者263例263眼的病例资料，均取右眼进行分析。应用可视化角膜生物力学分析仪（Corvis ST）对患者的角膜形变参数，包括第1次压平时间（A1T）、第1次压平长度（A1L）、第1次压平速度（A1V）、第2次压平时间（A2T）、第2次压平长度（A2L）、第2次压平速度（A2V）、产生最大压陷的时间（HCT）、最大压陷时的变形幅度（HCDA）、最大压陷时的峰距（HCPD）、最大压陷时的反向曲率半径（HCR）和非接触式眼压（IOPnct）等进行测量和分析；应用Pentacam眼前节分析系统测量中央角膜厚度（CCT）和6 mm直径范围的角膜前表面、后表面和全角膜垂直彗差、水平彗差、y向三叶草像差、x向三叶草像差、初级球差、总均方根（总RMS）、HOAs均方根（HOAs RMS）等HOAs。应用Pearson线性相关分析和多元逐步线性回归模型进行数据分析。结果近视眼的角膜生物力学特性与角膜HOAs间存在相关性；A1L与角膜前表面的初级球差、HOAs RMS，后表面的总RMS、HOAs RMS以及全角膜的HOAs RMS间均呈负相关（均P〈0.05）；HCR与角膜前表面、全角膜总RMS均呈负相关（均P〈0.05）。A2V与多种像差均相关。多元逐步线性回归模型分析显示，角膜前表面像差和全角膜像差与角膜生物力学参数间的相关性较弱，角膜后表面像差与角膜生物力学参数间的相关性相对较强。结论近视眼的角膜生物力学特性与角膜HOAs间存在相关性，角膜生物力学特性的变化主要与角膜后表面像差相关联，其或许有助于我们对早期圆锥角膜或扩张性角膜疾患的早期诊断。

Objective To investigate the correlations between corneal biomechanical properties and corneal high-order aberrations （HOAs） in myopic eyes.MethodsIn this retrospective study, 263 right eyes with myopia or myopic astigmatism were enrolled from January to October 2015 in Tianjin Eye Hospital.The values of first applanation time （A1T）, first applanation length （A1L）, first applanation velocity （A1V）, second applanation time （A2T）, second applanation length （A2L）, second applanation velocity （A2V）, highest concavity time （HCT）, highest concavity deformation amplitude （HCDA）, highest concavity peak distance （HCPD）, highest concavity radius （HCR） and non-contact intraocular pressure （IOPnct） were measured using the corneal visualization Scheimpflug technology （Corvis ST）. The central corneal thickness （CCT） and wavefront aberrations of the anterior, posterior surface, and the total cornea were measured with Pentacam.Pearson correlation and stepwise multivariate linear regression analysis were applied to analyze the correlations between biomechanical properties and corneal HOAs.This study follows the Helsinki declaration.The experiment was approved by the Ethic Committee of Tianjin Eye Hospital.Informed consent was signed from each patient.ResultsThere was a correlation between biomechanical properties and corneal HOAs.Negative correlations were found between A1L and the spherical aberration, HOAs RMS of anterior surface, total RMS and HOAs RMS of the posterior surface and HOAs RMS of the total cornea （P〈0.05）. HCRs were negatively correlated with total RMS of the total cornea and the anterior surface （P〈0.05）. The A2V was correlated with various aberrations.Multiple stepwise linear regression model analysis showed that, the correlation between the aberrations of anterior surface and biomechanical parameters, and the correlations between the total corneal aberration and biomechanical parameters were weak, the correlations between the aberrations of posterior surface and biomechanical parameters were strong.ConclusionsThere is a correlation between the biomechanical properties and corneal HOAs.The changes of the corneal biomechanical properties are mainly associated with the posterior corneal aberrations, which may contribute to the early diagnosis of subclinical keratoconus or dilated corneal disease.