There are many reasons for head not clear and black eyes, common causes are high blood pressure, vestibular migraine, intracranial lesions and so on. 1. Hypertension: hypertensive patients will have dizziness and black eyes when their blood pressure rises suddenly. 2. Vestibular migraine: patients generally manifest dizziness, blurred vision, and in more serious cases, nausea and vomiting. 3. Intracranial lesions: When intracranial lesions such as tumors occur, the tumor grows gradually and compresses the optic nerve over time, which will cause dizziness and black eyes. There may be other reasons, such as sudden standing when anemia, atherosclerotic plaque in neck blood vessels, vitreous hemorrhage, which may lead to unconsciousness and black eyes, and it is recommended to consult a doctor for treatment under the guidance of a doctor in time.