Contact lenses worn for a long time with red blood, may be caused by secondary infection, eye allergies, or dry eye, can be combined with the cause of the general treatment, medication and so on. 1. Secondary infection: If you don’t pay attention to personal hygiene during wearing contact lenses, or the disinfection of contact lenses is not thorough, it is very easy to be infected with bacteria and other microorganisms, which will lead to red blood in the eyes. Levofloxacin eye drops can be used to sterilize, and when the condition is more serious, systemic medication can be used, such as oral cephalosporin. 2. Eye allergy: If you are sensitive to the material of contact lenses, you are prone to allergic reactions after wearing them, and the above symptoms appear. Cetirizine can be taken orally as prescribed by the doctor to combat allergies. 3. Dry eye: wearing glasses for a long time may lead to changes in the quality of tears, thus causing dry eye, resulting in red eyes. Sodium vitrate eye drops can be used for treatment, which can provide moisturizing effect. If you wear contact lenses with the above several adverse reactions, you need to stop using them in time, and then change to frame glasses, but should be selected under the guidance of physicians.