I have encountered several such patients in the outpatient clinic, where the fundus examination could show signs of diabetic retinopathy, but the patient refused to admit to having diabetes. Because the unit organizes physical examination every year, the blood sugar is normal every year. In fact, the general physical examination does not completely exclude diabetes, because the physical examination measures fasting blood sugar. Some diabetic patients have normal fasting blood sugar, but only high postprandial blood sugar. Therefore, the physical examination fasting blood draw also has certain limitations, can consider the occasional post-meal blood draw, although there is a certain impact on the determination of liver and kidney function, but is more good than bad.