Inter- and Intra-Lamellar Slippage of Collagen Fibrils as a Potential Mechanism of Keratoconus Progression

Abstract

 

Purpose

 

To assess if inter- and intra-lamellar slippage of collagen fibrils may lead to progressive cone formation in keratoconus.

 

Methods

 

A generic finite element model of the human eye was generated that incorporates the micro-architecture of collagen fibrils in the corneo-scleral shell. Inter- and intra-lamellar slippage was simulated through residual strains of collagen fibrils using a microstructure-based constitutive formulation. Progressive inter- and intra-lamellar slippage was imposed to an eccentric, 4-mm-diameter area of the cornea while the model was subjected to normal IOP (15 mmHg). Topographic results were compared to clinical observation of a keratoconus patient with an eccentric cone.

 

Results

 

Increasing inter- and intra-lamellar slippage led to progressive cone formation of the cornea. The results were in good agreement with topographic observation of keratoconus patients with eccentric cone.

 

Conclusions

 

The numerical results support the assumption that inter- and intra-lamellar slippage of collagen fibrils may be the underlying mechanism that leads to progressive cone formation in keratoconus.

 

 

Numerical simulation of keratoconus progression showing the development of an eccentric cone due to inter- and intra-lamellar slippage of corneal collagen fibrils.

 

Keywords: 574 keratoconus