*Universidad del Norte, Barranquilla, Colombia †Instituto Barraquer de América, Bogotá, Colombia §Universidad de los Andes, Bogotá, Colombia ‡Centro Internacional de Métodos Computacionales en Ingenieréa (CIMEC)-INTEC-(UNL/CONICET), Universidad Nacional de Entre Ríos, Entre Ríos, Argentina.
J Glaucoma. 2013 Jan;22(1):10-4. doi: 10.1097/IJG.0b013e31822f4747.
There exists a concern about the general accuracy of intraocular pressure (IOP) measurements using tonometry, and especially Goldmann applanation tonometer (GAT) because it considers the cornea as an infinite thin shell. In this study, the relationship between the true IOP and tonometric IOP, external curvature radius (ECR), and central corneal thickness (CCT) is explored.
In this study, the calibration of the IOP measurements through GAT for different values of CCT, ECR, and E (Young modulus), is done through computational simulations of the mechanical behavior of the cornea subjected to the applanation process using the finite element method (FEM). Previous to this simulations, experimentations on rabbits were performed to confirm that inaccurate readings are obtained with GAT in certain conditions. This methodology is also followed to establish the range of corneal parameters of patients for which the GAT measure of pressure is reliable. The calibration equation for GAT measurements is developed from a statistical multiple linear regression analysis.
Based on a statistical variable analysis of the computational modeling results, a calibration equation is established for the GAT that relates the true IOP with the ECR, CCT, and GAT measurements.
Our results show that GAT measures are linearly dependent on the modulus of elasticity of the cornea; nevertheless, if we consider a healthy cornea with a specific modulus of elasticity, it is possible to correct the measure with a linear equation involving CCT and ECR.
眼压（IOP）测量的金氏压平眼压计（GAT）普遍准确性存在一定争议，因为它将角膜视为无限薄的壳。本研究旨在探讨真实IOP 与眼压计IOP、外部曲率半径（ECR）和角膜中央厚度（CCT）之间的关系。
本研究通过有限元法（FEM）模拟角膜在压平过程中的力学行为，对不同 CCT、ECR 和 E（杨氏模量）值下的 GAT IOP 测量进行了校准。在此之前，对兔子进行了实验，以确认在某些情况下 GAT 会得到不准确的读数。该方法还用于确定 GAT 压力测量可靠的患者角膜参数范围。GAT 测量的校准方程是通过统计多元线性回归分析得出的。
基于对计算模型结果的统计变量分析，建立了 GAT 的校准方程，将真实 IOP 与 ECR、CCT 和 GAT 测量值联系起来。
我们的结果表明，GAT 测量值与角膜弹性模量呈线性相关；然而，如果我们考虑具有特定弹性模量的健康角膜，则可以通过涉及 CCT 和 ECR 的线性方程对测量值进行校正。
