Modeling of the increased intraocular pressure effect on changes in the stress state of the eyeball’s internal structures

Abstract

The aim of the study was creating a model and evaluating the effect of elevated IOP in the anterior chamber during phacoemulsification on the changes in the stress state of various ocular structures. Materials and methods.A simplified axial symmetrical anatomical model of the eyeball was created using the finite element method. Using the Deform software package, the deformation problem was worked out by calculating the redistribution of the excess pressure in the anterior chamber during phacoemulsification, on the changes in the stress state of different ocular structures.Results. At processing of modeling results, data were obtained on redistribution of the excess pressure delivered to the anterior chamber towards its decrease in the posterior pole area. The pressure level amounted to 0.85 % of excess pressure applied. The findings are supported by few animal experiments. Conclusions.Proposed model of the increased IOP level effect on changes in the stressed state of various ocular structures demonstrates that the autoregulation mechanism maintaining ocular blood flow at a constant level includes a compensating mechanism for a steep IOP increase due to elastic properties of the vitreous body. This model allows calculating the redistribution of pressure in different parts of the eyeball, depending on the state of resilient-elastic properties of the vitreous, as well as on avitreal eyes, and in patients with silicone oil tamponade.