Biomechanics of chiasmal compression: Sensitivity of the mechanical behaviours of nerve fibres to variations in material property and geometry

Abstract

The mechanism of bitemporal hemianopia is still unclear. Previous research suggested that the nerve fibre packing pattern may contribute to the selective damage of nasal (crossed) nerve fibres. Numerical models were built using finite element modelling to study the biomechanics of optic nerve fibres. The sensitivity of the mechanical behaviours of the nerve fibres to variations of five parameters in the nerve fibre model were investigated using design of experiments (DOE). Results show that the crossing angle is a very significant factor that affects a wide range of responses of the model. The strain difference between the crossed and the uncrossed nerve fibres may account for the phenomenon of bitemporal hemianopia. This work also highlights the need for more accurate material properties of the tissues in the model and an improved understanding of the microstructure of the optic chiasm.