Embedded Collagen Deformation Models for Computational Modeling of Healthy, Keratoconic, and Crosslinked Corneas

Abstract

Collagen plays an extremely important role in carrying forces and maintaining the shape of the cornea. In keratoconus, the cornea shape can become distorted to the extent that normal vision is impossible, and the amount crosslinking between collagen fibrils are generally lower than in healthy eyes. In contrast, riboflavin-induced crosslinks can strengthen and stiffen the cornea. This article examined quantitatively how the extent of crosslinking in collagen fibrils influences the overall mechanical behavior of corneal tissue. Three models for the stress–strain behavior of the fibrils were examined, which is a function of the crosslink density within the fibrils. These models were then embedded in a matrix model, and tensile tests of cornea strips were examined using a finite element program. Results were compared with experiments from the literature for both normal and crosslinked corneas.

Finite element modelling of cornea mechanics: a review

“…Using shell elements, they investigated how variations in IOP and material properties of the cornea (i.e., decrease in rigidity of the cornea) can lead to a localized increase in corneal curvature. Foster et al (54) examined the stiffening effect of CXL in corneal tissue, fitting the material parameters to experiments on corneal strips.…”