Abstract:Objective Under high intraocular pressure, the deformation of the lamina cribrosa compresses the axons of retinal ganglion cells (RGCs) passing through it, leading to axonal damage and axoplasmic flow blockage. Therefore, studying the mechanical properties of the lamina cribrosa is of great significance. The lamina cribrosa region, comprising the lamina cribrosa and RGC axons, can be regarded as a typical heterogeneous composite material. This study aims to simulate indentation experiments using the finite element method to investigate the relationship between the mechanical properties of the tissues of the lamina cribrosa region and the contact area during indentation, and to propose a method for determining the mechanical properties of the lamina cribrosa and RGC axons. Methods Based on the microstructure of the tissues of lamina cribrosa region in rats and cats, an idealized three-dimensional finite element model of the heterogeneous composite material representing the lamina cribrosa region was established. The finite element method was used to simulate the indentation process of a spherical indenter, generating load-depth curves for various porosities of lamina cribrosa. Using dimensional analysis principles to obtain the modulus ratio of the lamina cribrosa to RGC axons in the lamina cribrosa region tissues, as well as the relationship between the indentation load, porosity, mechanical properties of the lamina cribrosa, and mechanical properties of RGC axons, thereby determining the mechanical properties of the lamina cribrosa and RGC axons. Results An empirical formula was used to obtain the modulus ratio and the effective elastic modulus of each component in the lamina cribrosa region tissues under indentation, and numerical examples verified the validity of the method for determining the modulus ratio and the effective elastic modulus. The results showed that the errors in identifying the modulus ratio was less than 5%, and the effective elastic modulus was less than 6%. Conclusion By measuring the porosity of the lamina cribrosa region tissues, the mechanical properties of the lamina cribrosa could be obtained.