The redness and pain in the eye first depends on the specific area. If the redness and pain is in the eyelid, it may be an inflammation of the eyelid tissue, such as blepharitis, blepharitis, mydriasis, acute lacrimal gland or dacryocystitis, etc., which is usually caused by bacterial infections and requires topical or systemic antibiotics depending on the severity of the condition. If the redness and pain is in the eye, it may be conjunctivitis or keratitis, and antibiotics, antifungal or antiviral eye drops or ointments should be used topically, or systemically in severe cases, depending on the symptoms and laboratory tests (e.g., microbiological cultures of eye secretions). It may also be corneal epithelial abrasion, electrophthalmia, which is often very painful, but the pain disappears immediately after drops of surface anesthetics, and can be identified. In this case, antibiotic eye drops are needed to prevent infection, and eye medication to promote corneal epithelial growth is added. Acute attacks of glaucoma, acute iridocyclitis, and endophthalmitis can also cause painful eye redness and swelling, often accompanied by significant vision loss, which is more serious and requires prompt consultation to clarify the cause and targeted treatment. Therefore, eye redness and pain can occur in a variety of eye diseases, so if it occurs, please seek medical attention to clarify the cause in order to provide targeted treatment.