Posters

Biomechanics of the structurally anisotropic cornea

Poster Details

First Author: A.Daxer AUSTRIA

Co Author(s):                        

Abstract Details

Purpose:

The understanding of the biomechanics of the cornea is most important for the understanding of the behaviour of the cornea during and after corneal and refractive surgery as well as for the understanding of ectatic corneal diseases. Ananlytical models like that after Laplace are based on an isotropic wall of a sphere and are, therefore, very limited in ist applicability, while numerical concepts such as Finite Element Modelling (FEM) are laburous and applicable to a particular situation only. Here I present the spherical dome model of the cornea which is both, simple an effective.

Setting:

Gutsehen Eye Center and Department of Ophthalmology, Medical University of Innsbruck, Austria

Methods:

Ultrastructural and biomechanical analysis demonstrate considerable anisotropy of colagen fibril orientation inside the corneal stroma and limbus. This fact allows mathematical modeling of the cornea and to descibe the cornea as an isolated anisotropic spherical dome.

Results:

The new spherical dome model presented here describes the biomechanical behaviour of the cornea via a new effective formula where an anisotropy factor f represents the anisotropic arrangement of the corneal collagen lamellae centrally to the limbus. When setting the anisotropy factor to an isotropic value the model converges to the elastic sphere model after Laplace. The new spherical dome model allows the effective calculation of the biomechanical behaviour after kerato-refractive procedures more realistic as the currently available approaches.

Conclusions:

The results show that current considerations from isotropic models, including FEM and the elastic sphere model after Laplace, overestimate the weakening of the cornea induced by corneal refractive procedures such as PRK and LASIK.

Financial Disclosure:

NONE