Red blood in the eyes all the time may be physiological, or may be caused by staying up all night, conjunctivitis and so on. 1. Physiological: The surface of the eyes is covered with conjunctiva, which is composed of capillaries, and the redness seen on the surface of the eyes is these capillaries. 2. Staying up late: staying up late causes the blood circulation around the eyes to deteriorate, and the blood vessels in the conjunctiva become congested to a certain extent, resulting in redness on the surface of the eyes. 3. Conjunctivitis: Conjunctivitis occurs when the conjunctiva is infected by bacteria, and the inflammation stimulates the conjunctival blood vessels to become congested, leading to redness in the eyes. When the eyes appear red blood, pay attention to rest, can to a certain extent to relieve the symptoms; if the patient has dry eyes, eye pain, eye itching and other symptoms, must promptly seek medical treatment.