A blackness in front of the eyes may be a result of ischemia and hypoxia in the brain, which mostly occurs due to insufficient blood supply to the brain, including insufficient blood supply to the brain and insufficient blood supply to the cerebellum. Patients with inadequate blood supply to the brain can have a blackness in front of the eyes, and patients with inadequate blood supply to the cerebellum can have dizziness, balance disorders and ataxia. The cervical vascular ultrasound, blood lipids, blood glucose and blood pressure should be checked, and if necessary, oral Cipro and Ginkgo biloba drops can be taken to improve blood circulation. Low blood glucose should be corrected promptly by oral saline or chocolate, and if necessary, intravenous hypertonic glucose infusion for rapid correction. Severe hypoglycemia or chronic hypoglycemia may cause hypoglycemic encephalopathy, which may cause irreversible damage to the brain nerves and may even endanger the life of the patient. In addition, it may also be caused by low blood pressure, which may cause sudden changes in body position, such as sitting or lying down, and sudden standing up may cause transient ischemia in the brain, which may also cause blackness in front of the eyes. The above-mentioned factors cause blackness in front of the eyes when the movement should be slowed down a bit.