[Retinal vein occlusion. I. Pathophysiology of thrombosis and etiopathogenesis of retinal vein occlusion].

The author submits contemporary views on thrombosis. In all intravascular thromboses three mechanisms participate in varying extents: humoral, i.e. haemocoagulation, fibrinolytic and thrombocyte disorders, disorders of the vascular wall and rheological and haemodynamic disorders resp. Mechanisms of thrombosis are interlinked, activation of one group as a rule does not lead to the development of a thrombus unless it is particularly intense. As a rule combination with another group of factors is necessary. In case of venous thrombosis a key role is played by a combination of stasis and activation of the blood clotting system. In the aetiopathogenesis of occlusion of the retinal vein the author considers impairment of the vascular wall the key factor which leads to changes of the rheological conditions which predispose to thrombosis. The author describes the so-called critical retardation of the blood flow in the retinal vein as the critical level of changed rheological condition humoral factors begin to play a clinical role when in thrombogenesis. On this predisposed background humoral factors act and the result is occlusion of the retinal vein. The author considers occlusion proper a process which develops for a long time and the occlusion of the retinal vein is the final link of a long and very complicated process which is multifactorial and very variable.