# Addressing Parameter Variability in Corneal Biomechanical Models: A Stepwise Approach for Parameters’ Optimization

## TL;DR

This paper introduces a stepwise method to optimize corneal material model parameters, aiming to reduce variability and improve reliability in biomechanical modeling.

## Contribution

A novel stepwise approach is proposed to separately estimate isotropic and anisotropic components in corneal biomechanical models.

## Key findings

- The stepwise approach reduces variability in parameter sets by isolating isotropic and anisotropic components.
- The methodology improves the reliability of corneal material model parameters for clinical and biomimetic applications.

## Abstract

Biomechanical modeling of the cornea is crucial for understanding the progression of some ocular diseases and optimizing surgical treatments. However, hyperelastic non-linear material models, such as those used for corneal tissue, often yield highly variable parameter sets in the scientific literature, influenced by factors like the chosen optimization intervals and differences between tensile and inflation test curve optimization, both of which are addressed in this study. This variability complicates the understanding of corneal mechanical properties. In this research, the aim is to optimize and calibrate the key parameters of the corneal material model, particularly focusing on c1, c2, k1 and k2, using the Holzapfel–Gasser–Ogden (HGO) hyperelastic model, and a novel methodology is proposed that separately estimates the isotropic and anisotropic components in a stepwise manner, addressing the issue of multiple parameter sets fitting experimental curves similarly. This approach helps to standardize corneal material models and improve the reliability of parameter estimations. Moreover, accurate biomechanical characterization within this framework contributes not only to clinical applications but also to biomimetics, inspiring the design of artificial corneal substitutes and bioengineered materials.