Three-dimensional Spherical Symmetry Model Analysis of Corneal Deformation

Abstract

In order to analyze the deformation response of the intact cornea to the physiological Intraocular pressures (IOPs), in this article, a spherical probe was used to indent the intact cornea and test the mechanical properties of cornea. Then, the JKR model of contact mechanics was used to get the corneal equivalent elastic modulus value in different IOP. On this basis, the cornea was simplified as spherically symmetric model. The three dimensional strain values of corneal integrity on different IOP were calculated by elastic theory. Besides, the effects of corneal thickness and Poisson’s ratio on the strain values were discussed. The results show that the intact cornea presented tension and compressive strain responses to physiological intraocular pressure in the circumferential and radial directions, respectively. The corneal circumferential and radial strain increased with corneal thickness. With the increase of Poisson’s ratio, the circumferential strain decreased and the radial strain increased. The results suggested an antagonistic effect between corneal circumferential and radial strain, which made the whole cornea respond to the change of intraocular pressure with uniform volume deformation. The results of this study are helpful to quantitatively analyze the biomechanical properties of cornea under different intraocular pressures, and can provide a reference for the numerical modeling and simulation of corneal mechanics.

Keywords

• intraocular pressure
• indentation test
• jkr-model
• volumetric strain
• cornea