Biomechanical Model of the Human Eye on the Base of Nonlinear Shell Theory

Abstract

The goal of this work is the development of a biomechanical model of the human eye and to prove software simulation systems of measuring the intraocular pressure (IOP) by an optical analyzer. We numerically simulate the eye deformation when the IOP is measured using the Ocular Response Analyzer developed by the USA company Reichert. The biomechanical model includes a cornea and a sclera, which are considered as axisymmetrically deformable shells of revolution with fixed boundaries; the space between these shells is filled with incompressible fluid. Nonlinear shell theory is used to describe the stressed and strained state of the cornea and sclera. The optical system is calculated from the viewpoint of the geometrical optics. Dependences between the pressure in the air jet and the area of the surface reflecting the light into a photo detector for the different thickness of the cornea were obtained. Three problems with different boundary conditions were considered. The shapes of the regions on the cornea surface were found from which the reflected light falls on the photo detector. First, the light is reflected from the center of the cornea, but then, as the cornea deforms, the light is reflected from its periphery. The numerical results make it possible to better interpret the measurement data. This work was supported by a grant No. 13-01-00801 from the Russian Foundation for Basic Research.