A Combined Approach for the Analysis of Ocular Fluid Dynamics in the Presence of Saccadic Movements

One of the main ocular diseases is age-related macular degeneration, actually treated with antibodies injections into the eye. This problem has been faced by computational approaches, taking into account either the influence of the tissues surrounding the vitreous, or the saccades. The aim of this work is to propose a combined fluid dynamic model of the vitreous chamber that analyses the impact of the saccades on the fluid dynamic mechanisms. The ocular vitreous humor was modeled considering liquefaction occurring in presence of age-related macular degeneration. We identified two kinds of boundary conditions, one related to the physiological environment outside the chamber, and one related to the saccades. The scleral hydraulic conductivity was evaluated by means of experimental permeability tests. An exponential decay was used to describe the trend of the scleral hydraulic conductivity with the acting pressure drop. The streamline analysis shows two main stagnant regions on the equatorial plane and peculiar fluid dynamics in absence of saccades. This study demonstrates the major role played by the saccades in determining the fluid dynamic mechanisms inside the vitreous chamber of the eye and represents a powerful tool to investigate vitreous dynamics and its relation to clinical issues.