There are many reasons why patients sometimes have symptoms of blackout, for example, when squatting for a long time or lying down and suddenly getting up too quickly and violently, transient postural hypotension causes insufficient cerebral perfusion, and patients will have symptoms of blackout and dizziness. Transient ischemic attack of the internal carotid artery system may also lead to the symptom of darkness in front of the eyes, and there may be other symptoms of ischemia of the internal carotid artery system, such as hemiparesis or hemiplegia, monocular visual impairment, and so on. Therefore, it is recommended to consult the hospital for timely examination when the patient has the symptom of darkness in front of the eyes, and can do ultrasound or transcranial Doppler examination of carotid blood vessels to determine the blood supply of the internal carotid artery system initially. If the internal carotid artery system is considered to have stenosis, head CTA examination should be done to clarify, and treatment should be given according to the results.