The cause of redness in the eyes is always determined by the presence of other symptoms in the eyes. If there is eye discharge in addition to redness, it is usually a sign of an infectious disease such as bacterial conjunctivitis, keratitis or viral conjunctivitis or keratitis. If there is no eye discharge and the vision is normal, it may be a sign of dry eye or eye fatigue. If there is redness and localized pain in the eyes and vision loss is more obvious, it may be a sign of scleritis or uveitis, glaucoma, or other diseases. So if you have this symptom, you need to go to the hospital for a comprehensive examination as soon as possible to understand the specific cause of the disease, so that the treatment can be more targeted.