The central retinal vein (retinal vein) is a short vein that runs through the optic nerve and drains blood from the capillaries of the retina into the larger veins outside the eye. The anatomy of the veins of the orbit of the eye varies between individuals, and in some the central retinal vein drains into the superior ophthalmic vein, and in some it drains directly into the cavernous sinus. [WP,unvetted]. [ http://en.wikipedia.org/wiki/Central_retinal_vein ]