Outflow of aqueous humour occurs by two routes. Approximately 80 % of total outflow is through the trabecular meshwork into the canal of schlemn into the venous circulation via the aqueous veins. The remaining 20% is accounted for by the uveoscleral pathways: through the ciliary body into the suprachoroidal space, to be drained into the ciliary body, choroid, and sclera via the venous circulation.