Biomechanical analysis of the human eye after the surgical correction of hyperopia

Abstract

Changes in the stress-strain state of the cornea and in the intraocular pressure (IOP) readings obtained by Goldmann (GAT) and Maklakov (MAT) applanation tonometers after hyperopia correction surgery are discussed. Two types of refractive correction procedures (LASIK and IntraLASIK) are considered. In the ANSYS software package the corneasclera elastic system is presented as two conjugate transversely isotropic spherical segments loaded with internal pressure. The cornea is simulated as a multi-layered transversely isotropic elastic shell and the sclera is modelled by a transversely isotropic homogeneous elastic shell. In order to estimate changes of the IOP readings obtained by GAT and MAT after hyperopia surgery the problem of deformation of the cornea under the load with a flat base is considered. The IOP readings before and after the surgeries for two types of tonometers are compared for the same value of true IOP.