Modelling aqueous humor outflow through trabecular meshwork

A simple model of aqueous outflow through the trabecular meshwork in eye has been developed. The model considers the meshwork as an annular cylindrical ring with uniform thickness of homogenous, isotropic, viscoelastic material, swollen with continuously percolating aqueous humor through it. It incorporates a strain-dependent permeability function into Darcy's law which is coupled to the force balance for the bulk material. A simple analytical expression relating aqueous flux to pressure differential is developed which shows how strain-dependent permeability can lead to reduction in hydraulic conductivity (aqueous outflow facility) with increasing intraocular pressure (IOP) as observed in experiments by ophthalmologists. Analytical expressions for the displacement, fluid pressure and dilatation in the trabecular meshwork have been obtained. (c) 2006 Elsevier Inc. All rights reserved.