A Model for the Human Cornea. Constitutive Behavior and Numerical Analysis

The human cornea (the external lens of the eye) has the macroscopic structure of a thin shell, originated by the organization of collagen lamellae parallel to the middle surface of the shell. The lamellae, composed by bundles of collagen fibrils, are responsible for the experimentally observed anisotropy of the cornea. Anomalies in the fibril structure may explain the changes in the mechanical behavior of the tissue observed in pathologies such as keratoconus. We propose a numerical model for the human cornea that is able to account for its mechanical behavior in normal conditions or in presence of keratoconus. An anisotropic material model is used in a finite element framework to simulate the response of healthy and degenerated corneas under increasing values of the intraocular pressure. The ability of our model to reproduce the behavior of the human cornea opens a promising perspective for the numerical simulation of refractive surgery.