Common causes of red blood in the eyes include overuse of the eyes, conjunctivitis, and improper eye care. If it is overuse of the eyes, you need to let the eyes fully rest, scientific eye use; if it is conjunctivitis, you need to use levofloxacin eye drops and other medications; if it is improper care, you need to reduce the wearing of contact lenses, the use of cosmetics and so on. 1. Excessive eye use: If you stay up late for a long time, use computers and electronic products for a long time, and your eyes do not get enough rest, your eyes will become red because of excessive fatigue, you should use your eyes in a scientific way, and take a rest after an hour of work or study with your eyes closed or look into the distance for a while, and at the same time take regular rest and avoid staying up all night. 2. Conjunctivitis: Conjunctivitis is an inflammation of the eye caused by bacterial and viral infections in the eye, which is characterized by redness, pain, and purulent discharge, etc. It is necessary to consult a doctor for timely treatment, and to use ofloxacin eye drops and other medications under the guidance of a doctor. 3. Improper eye care: daily often wear contact lenses for a long time, excessive make-up and so on can also cause eye redness, long time wearing contact lenses will lead to corneal hypoxia, local vasodilatation, and in serious cases, even complicate the infection, cosmetics and other powders are easy to fall into the eye to stimulate the production of redness, so you should reduce the use of contact lenses and cosmetics. If the symptoms are serious, you need to consult a doctor in time to avoid delaying the condition and affecting your vision, and strictly follow the doctor’s instructions for treatment.