Pavlou, Michael J.. A mechanics based analytical model of vitreous motion and vitreous detachment in the human eye when subjected to saccadic movement. Retrieved from https://doi.org/doi:10.7282/T37H1P03
DescriptionIn the human eye, the detachment behavior of the vitreous cortex from the sensory retina is clinically significant as this pathology is highly correlated with rhegmatogenous retinal detachment, a serious eye condition that can result in vision loss. A mechanics based mathematical model for vitreo-retinal detachment in the human eye when subjected to saccadic eye motion is presented in this dissertation. The problem is formulated as a two-dimensional propagating boundary value viscoelasticity problem in the calculus of variations. This formulation yields the governing equations of the vitreous body, boundary conditions, matching conditions and a transversality condition which, in turn, yields the detachment criterion during a saccade. The first part of the dissertation studies a constrained two-dimensional model where only the dominant motion of the vitreous is considered. Closed form analytical solutions of the coupled set of partial differential equations are obtained via modal analysis of a vibrating two-dimensional continuum with non-periodic loading. Results of numerical simulations are presented, ultimately revealing the evolution of the detachment of the vitreo-retinal interface. In the second part of the dissertation, fully two-dimensional motion of the vitreous is considered. A semi-analytical solution is obtained via the Rayleigh-Ritz method in combination with modal analysis. Results are compared to the constrained two-dimensional model, as well as to clinically observed data and previously published experimental and numerical studies. The material properties of the human vitreous are both difficult to study, and change significantly with age and other factors. The effects of these properties on the motion of the vitreous and the detachment behavior of the vitreo-retinal interface are studied. The results of the present study indicate that if a saccade is large enough to cause further detachment of the vitreous from the retina, then the detachment will progress until it reaches a point of abnormal vitreo-retinal adhesion.