Mathematical modelling of aqueous humour outflow from the eye through the pores in the lining endothelium of Schlemm's canal.

Aqueous humour leaves the eye mainly by way of pore openings in vacuolar swellings in the endothelial cells which line the wall of Schlemm's canal. Calculation of the resistance to fluid flow offered by these small pores requires data on their incidence and dimensions linked to a suitable mathematical model. Data are derived from scanning electron microscopy (SEM) studies conducted on rhesus monkey eyes maintained at an intraocular pressure (IOP) of either 8 or 15 mmHg and on human eyes either untreated controls or treated with pilocarpine. Mathematical models of flow through the pore openings are developed. Application of a Venturi tube model to the SEM data shows that the pore resistance of rhesus monkey eyes at 8 mmHg was seventeen times greater than that at 15 mmHg while the pore resistance in untreated human eyes was five times greater than in eyes which received pilocarpine.