Central retinal vein occlusion (CRVO) results from a blockage in the central retinal vein, located in the optic nerve. In this animation, Sanjay Sharma explains the pathophysiology of CRVO including elasticity changes in the arterial vessel, clot formation and lumen occlusion. Dilated tortuous vessels and vessel wall rupture leading to blood and serum leakage into the retina are illustrated in cross-section.