Patients sit down, stand up when the symptoms of darkness in front of the eyes, the reasons are as follows: 1, postural hypotension: because the blood pressure adjustment is not timely will lead to cerebral perfusion transient insufficiency, the patient will appear in front of the eyes of the black or unsteady, usually in a few seconds on the quick relief, patients often have this situation, it is recommended that the hospital for prone position blood pressure measurement, if the blood pressure is low, patients can normally Oral pulse drink, or drink more soybean milk to enhance the physique, in general to participate in more physical activities, help the regulation of vascular elasticity; 2, anemia: to check the blood routine clearly, the patient should also pay attention to the usual in the get up must be slow, because stand down, sit down and stand up suddenly this dizziness, may lead to fainting, caused by unnecessary fall injury.