Cabrera Fernández Delia, Niazy A M, Kurtz R M, Djotyan G P, Juhasz T
University of Miami, Department of Ophthalmology, Miller School of Medicine, Bascom Palmer Eye Institute, Miami, Florida 33136, USA.
J Biomed Opt. 2005 Nov-Dec;10(6):064018. doi: 10.1117/1.2136149.
A 2-D finite element model of the cornea is developed to simulate corneal reshaping and the resulting deformation induced by refractive surgery. In the numerical simulations, linear and nonlinear elastic models are applied when stiffness inhomogeneities varying with depth are considered. Multiple simulations are created that employ different geometric configurations for the removal of the corneal tissue. Side-by-side comparisons of the different constitutive laws are also performed. To facilitate the comparison, the material property constants are identified from the same experimental data, which are obtained from mechanical tests on corneal strips and membrane inflation experiments. We then validate the resulting models by comparing computed refractive power changes with clinical results. Tissue deformations created by simulated corneal tissue removal using finite elements are consistent with clinically observed postsurgical results. The model developed provides a much more predictable refractive outcome when the stiffness inhomogeneities of the cornea and nonlinearities of the deformations are included in the simulations. Finite element analysis is a useful tool for modeling surgical effects on the cornea and developing a better understanding of the biomechanics of the cornea. The creation of patient-specific simulations would allow surgical outcomes to be predicted based on individualized finite element models.
建立了角膜的二维有限元模型，以模拟角膜重塑以及屈光手术引起的变形。在数值模拟中，当考虑随深度变化的刚度不均匀性时，应用线性和非线性弹性模型。创建了多个模拟，采用不同的几何构型来去除角膜组织。还对不同的本构定律进行了并排比较。为便于比较，材料特性常数从相同的实验数据中确定，这些数据来自对角膜条带的力学测试和膜膨胀实验。然后，通过将计算得到的屈光力变化与临床结果进行比较，验证所得模型。使用有限元模拟角膜组织切除所产生的组织变形与临床观察到的术后结果一致。当在模拟中考虑角膜的刚度不均匀性和变形的非线性时，所开发的模型提供了更可预测的屈光结果。有限元分析是一种用于模拟手术对角膜的影响以及更好地理解角膜生物力学的有用工具。创建患者特异性模拟将允许基于个体化有限元模型预测手术结果。
