Corneal deformation mapping and FE-based strain analysis via digital image correlation: Biomechanical changes after...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Materials Science

Background:

• Accurate corneal mechanical property assessment is vital for ocular biomechanics, refractive surgery outcomes, and cross-linking (CXL) optimization.
• Traditional methods like uniaxial tensile testing have limitations in simulating in vivo conditions.
• Inflation testing offers a more physiological stress state but lacks detailed deformation mapping.

Purpose of the Study:

• To develop and validate an integrated experimental-computational protocol for quantifying corneal biomechanical changes.
• To assess the localized stiffening effects of CXL and increased compliance from stromal ablation.
• To enable quantitative evaluation of treatment-induced biomechanical alterations in the cornea.

Main Methods:

• Combined inflation testing of porcine eyes with high-resolution 3D digital image correlation (3D-DIC).
• Analyzed three cohorts: controls, CXL-treated, and femtosecond laser-ablated corneas under controlled intraocular pressure (IOP).
• Utilized membrane theory and 3D finite element modeling for strain quantification and parameter identification.

Main Results:

• 3D-DIC provided dense, pointwise displacement and strain maps of the corneal anterior surface.
• Successfully quantified localized stiffening from CXL and increased compliance from stromal ablation.
• Established an end-to-end method for evaluating treatment-induced biomechanical changes.

Conclusions:

• The integrated protocol accurately quantifies regional corneal biomechanical properties.
• This method allows for precise evaluation of the effects of CXL and laser ablation on corneal tissue.
• The approach provides a foundation for improved understanding and prediction in ophthalmic procedures.