There are many reasons for the sudden appearance of dizziness and blurred vision: 1) If the patient has hypertension, the sudden appearance of dizziness and blurred vision should be considered to be caused by elevated blood pressure, which can be clarified by blood pressure measurement. 2) If the patient is middle-aged or old, and has cerebral arteriosclerosis and cerebral stenosis, the sudden appearance of dizziness and blurred vision should be considered to be caused by cerebral vascular spasm and insufficient cerebral blood supply, which can be clarified by transcranial Doppler examination. Doppler examination can be done to clarify. 3, if the patient’s body temperature rises during a cold or fever, it can also lead to sudden dizziness and blurred vision, which may be accompanied by muscle aches and discomfort. 4, sudden dizziness and blurred vision may also be caused by hypoglycemia, and if the patient is accompanied by heart palpitations, palpitations, and sweating, it can be clarified by measuring the fingertip glucose. 5, sudden dizziness and blurred vision after giving food can be caused by the patient’s blood sugar. 6, sudden dizziness and blurred vision after giving food can be caused by the patient’s blood sugar. The symptoms of dizziness and lightheadedness are relieved after giving food to the patient, indicating that it is related to hypoglycemia.