Sudden blackness in front of the eyes for a few seconds: 1. Consider insufficient cerebral perfusion caused by low blood pressure; 2. Dizziness episodes due to low blood sugar; 3. May be caused by insufficient transient blood supply to the brain. If blood pressure is usually low, during the process of dizziness or blackness or blurring in front of the eyes, attention needs to be paid to maintain a sitting or lying position to ensure adequate cerebral perfusion. Usually, you need to drink more water and supplement sufficient fluid intake to ensure sufficient cerebral perfusion and improve the symptoms of dizziness and blackness. For some people who have diabetes or usually eat less, or in the process of some weight loss, they usually have the symptoms of hypoglycemia with blackness in front of their eyes. When hypoglycemia occurs, it is also accompanied by dizziness, panic, sweating, nausea and vomiting. When hypoglycemia occurs, it is necessary to replenish sugar and eat in time to improve the symptoms of hypoglycemia. If the symptoms of blackness and dizziness occur frequently, it is necessary to go to the neurology department for timely consultation and comprehensive diagnosis through specific physical examination and head imaging and physical examination.