Biomechanics of Aqueous Humor Outflow Resistance*

Conventional aqueous outflow pathway – Comprised of the trabecular meshwork, the juxtacanalicular connective tissue, the endothelial lining of Schlemm’s canal, Schlemm’s canal itself, the collecting channels, and aqueous veins. Flow resistance – The flow resistance (R=DP/Q) of a tissue is the ratio between the pressure drop across that tissue (DP) and the flow rate generated by that pressure drop (Q). Giant vacuoles – The outpouchings of the inner-wall endothelium of Schlemm’s canal into its lumen. They are caused by the pressure drop across inner-wall endothelial cells. Hydraulic conductivity (Lp) – A measure of the ease with which a fluid passes through a tissue: Lp=Q/A/DP where A is the cross-sectional area of the tissue facing flow. Inner-wall region – Comprised of the inner-wall endothelium of Schlemm’s canal, its basement membrane, and the adjacent juxtacanalicular tissue. Laser trabeculoplasty – The surgical treatment of glaucoma, in which a laser beam is focused on the trabecular meshwork making tiny, evenly spaced burns.