Multi-physics modeling and finite element formulation of corneal UV cross-linking

Biomech Model Mechanobiol. 2021 Aug;20(4):1561-1578. doi: 10.1007/s10237-021-01463-3. Epub 2021 May 19.

Abstract

The UV cross-linking technique applied to the cornea is a popular and effective therapy for eye diseases such as keratoconus and ectatic disorders. The treatment strengthens the cornea by forming new cross-links via photochemical reactions and, in turn, prevents the disease from further developing. To better understand and capture the underlying mechanisms, we develop a multi-physics model that considers the migration of the riboflavin (i.e., the photo-initializer), UV light absorption, the photochemical reaction that forms the cross-links, and biomechanical changes caused by changes to the microstructure. Our model is calibrated to a set of nanoindentation tests on UV cross-linked corneas from the literature. Additionally, we implement our multi-physics model numerically into a commercial finite element software. We also compare our simulation against a set of inflation tests from the literature. The simulation capability allows us to make quantitative predictions of a therapy's outcomes in full 3-D, based on the actual corneal geometry; it also helps medical practitioners with surgical planning.

Keywords: Biological material; Finite elements; Multi-field problems; UV cross-linking.

MeSH terms

  • Biomechanical Phenomena
  • Calibration
  • Computer Simulation
  • Cornea / physiology*
  • Cross-Linking Reagents
  • Elasticity
  • Finite Element Analysis
  • Humans
  • Keratoconus / metabolism*
  • Keratoconus / therapy*
  • Physics
  • Riboflavin / pharmacology*
  • Shear Strength
  • Ultraviolet Rays

Substances

  • Cross-Linking Reagents
  • Riboflavin