Mercer Ryan N, Waring George O, Roberts Cynthia J, Jhanji Vishal, Wang Yumeng, Filho Joao S, Hemings Richard A, Rocha Karolinne M
J Refract Surg. 2017 Sep 1;33(9):625-631. doi: 10.3928/1081597X-20170621-03.
To evaluate and compare biomechanical properties in normal and keratoconic eyes using a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (Corvis ST; Oculus Optikgeräte GmbH, Wetzlar, Germany).
This retrospective study evaluated 89 eyes (47 normal, 42 keratoconic) and a validation arm of 72 eyes (33 normal, 39 keratoconic) using the Corvis ST. A diagnosis of keratoconus was established by clinical findings confirmed by topography and tomography. Dynamic corneal response parameters collected by the Corvis ST (A1 velocity, deformation amplitude [DA], DA Ratio Max 1mm, and Max Inverse Radius) and a stiffness parameter at first applanation (SP-A1) were incorporated into a novel logistic regression equation (DCR index). Area under the receiver operating curve (AUC) was used to assess the sensitivity and specificity of the DCR index.
DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1 were each found to be statistically significantly different between normal and keratoconic eyes (Mann-Whitney test [independent samples]; P = .0077, < .0001, < .0001, and < .0001, respectively; significance level: P < .05). DCR index demonstrated high sensitivity, specificity, and overall correct detection rate (92.9%, 95.7%, and 94.4%, respectively; AUC = 98.5). The sensitivity and overall correct detection rate improved when eyes with Topographical Keratoconus Classification grades (TKC) greater than 0 were reevaluated (from 92.9% to 96.6% and from 94.4% to 96.1%, respectively).
Combining multiple biomechanical parameters (A1 velocity, DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1) into a logistic regression equation allows for high sensitivity and specificity for distinguishing keratoconic from normal eyes. [J Refract Surg. 2017;33(9):625-631.].
使用配备非接触眼压计（Corvis ST；德国韦茨拉尔的Oculus Optikgeräte GmbH公司）的动态超高速Scheimpflug相机，评估并比较正常眼和圆锥角膜眼的生物力学特性。
这项回顾性研究使用Corvis ST评估了89只眼（47只正常眼，42只圆锥角膜眼）以及一个包含72只眼（33只正常眼，39只圆锥角膜眼）的验证组。圆锥角膜的诊断通过地形图和断层扫描确认的临床发现来确定。将Corvis ST收集的动态角膜反应参数（A1速度、变形幅度[DA]、DA Ratio Max 1mm和最大反半径）以及首次压平处的刚度参数（SP-A1）纳入一个新的逻辑回归方程（DCR指数）。使用受试者工作特征曲线下面积（AUC）来评估DCR指数的敏感性和特异性。
发现正常眼和圆锥角膜眼之间的DA、DA Ratio Max 1mm、最大反半径和SP-A1在统计学上均有显著差异（曼-惠特尼检验[独立样本]；P分别为0.0077、<0.0001、<0.0001和<0.0001；显著性水平：P<0.05）。DCR指数显示出高敏感性、特异性和总体正确检测率（分别为92.9%、95.7%和94.4%；AUC = 98.5）。当重新评估地形性圆锥角膜分类等级（TKC）大于0的眼时，敏感性和总体正确检测率有所提高（分别从92.9%提高到96.6%，从94.4%提高到96.1%）。
将多个生物力学参数（A1速度、DA、DA Ratio Max 1mm、最大反半径和SP-A1）纳入逻辑回归方程可实现区分圆锥角膜眼和正常眼的高敏感性和特异性。[《屈光手术杂志》。2017；33(9)：625 - 631。]
