Fig. 10 Venous drainage system of the eye. Aqueous enters Schlemm's canal and then penetrates through the intrascleral channels (aqueous veins of Ascher). Portions of the aqueous veins are visible at the limbus. The episcleral vessels drain to the anterior ciliary vessels, which along with the vortex veins drain to the ophthalmic vein and then the cavernous sinus.