NBEO Ocular Anatomy Posterior Segment and Cranial Nerves Practice Test 2026 - Free NBEO Practice Questions and Study Guide

The outer retinal layers rely on the choroidal circulation for nourishment, and their venous outflow follows the choroid. Blood from the choroid drains primarily through the vortex veins, which collect this flow and typically empty into the ophthalmic venous system (via the superior or inferior ophthalmic veins) before reaching the cavernous sinus. In contrast, the central retinal vein handles drainage from the inner retina, not the outer layers. The ciliary veins drain the uveal tract more broadly, and the superior ophthalmic veins are part of the orbital drainage network but are not the principal path for the outer retina’s outflow.