Traction on the retina induced by saccadic movements in the presence of Posterior Vitreous Detachment

Vitreous humor, which fills most part of the eye's interior, is a gel-like substance in the young healthy man. With aging, it undergoes a liquefaction process that usually leads to vitreous separation from the retina, which is called Posterior Vitreous Detachment (PVD). Sites of strong adherence between the vitreous and the retina may prevent a complete detachment. In such circumstances the adherent vitreous fibers may pull so hard as to produce a retinal break. This rupture mechanism may possibly be induced by eye rotations. Our aim is to study the dynamic stress concentration on the retina induced by saccadic eye movements. While our formulation applies to a general three-dimensional problem, we consider a plane strain problem just to simplify the computational setting. The solid vitreous is modeled as a hyperelastic incompressible solid, endowed with a Mooney-Rivlin response function, and the liquefied vitreous as a Newtonian fluid. Moreover, we account for finite-amplitude eye rotations. We implemented our model in Comsol by using the PDE Application Mode in weak form and the Moving Mesh Application Mode. The numerical simulations show that very high values of the traction are attained at the boundary of the interface during eye rotations.