Central retinal vein occlusion is associated with systemic conditions, such as arterial hypertension, diabetes, hypercholesterolemia, but also with certain hypercoagulability states (thrombophilia). Growing evidence indicates, that the presence of antiphospholipid antibodies and elevated plasma homocysteine levels predispose to central retinal vein occlusion. In younger patients, factor V Leiden (Arg506Gln) could increase the risk of this disease. Other probable causes of thrombophilia related to retinal vein occlusion include increased levels of plasminogen activator inhibitor 1 and lipoprotein (a), which impair fibrinolysis.