3D simulation of the aqueous flow in the eye

Glaucoma is one of the leading causes of blindness in the world. It results in an increase of the aqueous humour (AH) outflow pathway which leads to an increase of the intraocular pressure (IOP). Many treatments exists to reduce and stabilize the IOP such as medications, filtering surgery and Glaucoma Drainage Devices. So far computational fluid dynamics (CFD) modeling of the eye drainage system has not yet been well studied. Therefore our goals was to numerically simulate the AH outflow pattern in a model of the eye to further simulate a healthy and glaucomatous eye and various forms of glaucoma surgery. In order to do so, a 3D CDF model of the eye was created based on real geometries. Two methods were tested to this aim. The first one consisted in the injection of a CT contrast agent in an enucleated rabbit eye and visualization by a CT scan. A segmentation process was then achieved on the resulting scans to reconstruct the eye structures. The second one was based on microphotography stacks of histology of human eye whereof digital processing of the eye structure images and 3D reconstruction of a numerical model were performed. Due to resolution limitations several ocular structures could not be extracted from the segmentation process. In the second method, simulations of pressure and flow velocity distribution in healthy eye gave results comparable to physiology. Modeling the glaucomatous eye led to an increase in the IOP around 37 mmHG. We have been able to model the 3D structure of the eye based on real geometry. Flow simulations gave interesting results for the IOP and the flow velocity on a healthy eye. Mimicking glaucoma conditions led to an increase of the IOP from normal range, which went down to lower values after a filtering procedure. Further refinements in the boundary conditions for the filtering procedure shall improve the precision and efficacy of this innovative tool for modeling glaucoma surgery