The sudden blackness in front of the eyes may be the result of a transient black cloud, which is often caused by postural hypotension, anemia, carotid artery stenosis, etc. 1, postural hypotension: due to long-term squatting, lying position factors, resulting in the accumulation of blood pressure in the lower part of the body, suddenly get up will lead to temporary ischemia of the tissues around the eyes, and then a transient The symptoms of black blindness. Usually pay attention not to get up too violently, when changing position, pay attention to keep the movement slow; 2, anemia: anemia may also lead to insufficient blood supply to the brain, the symptoms of transient blackout. Patients need to improve anemia by supplementing iron and other drugs under the guidance of professional doctors; they should pay attention to a balanced diet and increase iron-rich foods in daily life, such as animal liver, meat, shellfish, spinach, etc.; 3, carotid artery stenosis: the ophthalmic artery comes from the branches of the carotid artery, and if the carotid artery is stenosed, it may lead to insufficient blood supply to the ophthalmic artery, and transient blackout may also occur, commonly used Anti-platelet agglutination drugs, statins, etc.; 4, other: bradycardia, cervical spondylosis, hypoglycemia and other conditions can also lead to a sudden blackness in front of the patient’s eyes for a while and then well, the patient needs to be targeted according to the cause of the disease.