The main causes of dull eyes include lack of sleep, excessive rubbing of the eyes, etc., which is manifested as dull and lifeless eyes. 1. Dullness of the eyes may be caused by lack of sleep, so usually must pay attention to develop good sleeping habits and eye habits. Do not stay up all night, because staying up all night will make the blood flow of the eyes become slow and stagnant, in which case it is very easy to aggravate the local pigmentation, so that the skin of the eyes show darkness and so on. 2. Dullness of the eyes may also be caused by excessive rubbing of the eyes, usually due to allergies caused by itching, so that the patient is always unconsciously rubbing the eyes, and ultimately, the skin of the eyes become dull. If you have darkness under the eyes, you can actively seek medical advice, correct bad habits and follow the doctor’s instructions for reasonable treatment.