Purpose: To predict the shape of the interface between aqueous humor and a tamponade, gas or silicone oil (SO), in vitrectomized eyes. To quantify the tamponated retinal surface for various eye shapes, from emmetropic to highly myopic eyes.
Methods: We use a mathematical model to determine the equilibrium shape of the interface between the two fluids. The model is based on the VOF (volume of fluids) method. The governing equations are solved numerically using the free software OpenFOAM. We apply the model both to the case of idealized, yet realistic, geometries of emmetropic and myopic eyes and to a real geometry reconstructed from MRI images of the vitreous chamber.
Results: The numerical model allows us to compute the equilibrium shape of the interface between the aqueous humor and the tamponade fluid. From this we can compute the portion of the retinal surface that is effectively tamponated by the fluid. We compare the tamponating ability of gases and SOs. We also compare the tamponating effect in emmetropic and myopic eyes by computing both tamponated area and angular coverage.
Conclusion: The numerical results show that gases have better tamponating properties than SOs. We also show that, for a given filling ratio the percentage of tamponated retinal surface area is smaller in myopic eyes. The method is valuable for clinical purposes, especially in patients with pathological eye shapes, to predict the area of the retina that will be tamponated for a given amount of injected fluid.