There are various causes of conjunctival congestion: 1. inflammatory diseases of the eye, such as conjunctivitis (in addition to conjunctival congestion, often accompanied by other symptoms such as foreign body sensation, itching, burning sensation, increased secretion and even vision loss), keratitis (in addition to conjunctival congestion, often accompanied by eye pain, photophobia, vision loss and other symptoms), acute iridocyclitis (in addition to conjunctival congestion, often accompanied by eye pain, photophobia, vision loss and other symptoms), endophthalmitis, sclerositis, blepharitis, acute lacrimal glanditis, etc.; 2. (in addition to conjunctival congestion, often accompanied by eye pain, photophobia, vision loss, etc.), endophthalmitis, sclerositis, blepharitis, acute lacrimal glanditis, etc.; 2. acute episodes of acute angle-closure glaucoma (in addition to conjunctival congestion, often accompanied by eye pain, eye swelling, vision loss, and in some cases, systemic symptoms such as ipsilateral headache and nausea); 3. various ocular surface foreign bodies entering the eye (such as shampoo, perfume, and other irritating liquids; or iron filings, thread, hair scraps, cinder, wall skin, willow, etc.) In addition, various types of trauma, abnormal eyelid position resulting in exposure conjunctivitis (e.g., entropion, ectropion, ectropion, ectropion, ectropion, etc.); 4. In addition, conjunctival congestion can be caused by various types of trauma, exposed conjunctivitis due to abnormal eyelid position (e.g., intraocular impingement, ectropion, incomplete eyelid closure, congenital abnormalities of the eyelid, etc.), wearing contact lenses, lack of sleep, staying up late, after drinking, taking hot baths, and prolonged continuous eye use.