There are numerous clinical causes of ocular vascular occlusion, such as vascular inflammation, altered blood composition, embolism, vasospasm, and so on. 1. Inflammation of blood vessels: Inflammation of blood vessels may cause inflammatory cell infiltration, blood vessel damage, resulting in thrombosis, which may easily lead to ocular vascular occlusion. 2. Changes in blood composition: for example, the increase in red blood cells, platelets, platelet activity increases, which can lead to increased blood viscosity, which in turn can easily lead to ocular vascular occlusion. 3. Embolism dislodgement: once the embolism formed by the blood vessels in other parts of the body dislodge, it may accompany the flow of blood and enter into the fundus blood vessels to cause obstruction, which is commonly seen in cardiac insufficiency. 4. Vasospasm: patients generally do not have organic lesions, exertion, tension, stress and other conditions cause abnormal vascular contraction, also can lead to fundus vascular blockage. Eye vascular blockage can be big or small, need to be treated as soon as possible, so as not to miss the condition.