What causes sudden eye pain?

Generally, sudden eye pain may be caused by foreign bodies in the eye, eye strain, allergic conjunctivitis, bacterial keratitis, acute angle-closure glaucoma, and other reasons. It is recommended to seek medical attention promptly, identify the underlying cause, and receive symptomatic treatment under a doctor's guidance. Specific analyses are as follows:

1. Foreign body in the eye: Dust, sand, or other foreign objects entering the eye can directly rub against the cornea, causing sudden pain, often accompanied by tearing and frequent blinking. Immediately stop rubbing the eye; close the eye to allow natural flushing by tears, or gently rinse the eye with sterile saline solution. If the foreign body remains, it should be removed by a doctor using professional tools.

2. Eye strain: Prolonged screen time, staying up late, and similar behaviors can tense the eye muscles and reduce tear secretion, leading to sudden eye pain and dryness. Follow the 20-20-20 rule—look at something 20 feet away for 20 seconds every 20 minutes of screen use. Ensure 7–8 hours of sleep each night and apply a warm compress with a towel heated to around 40°C to the eyes for 10 minutes to relieve eye fatigue.

3. Allergic conjunctivitis: After exposure to allergens such as pollen or dust mites, an allergic reaction occurs in the conjunctiva, manifesting as sudden eye pain, itching, and redness. Quickly avoid the allergen, wear protective eyewear when outdoors, and use antiallergic eye drops such as levocabastine hydrochloride, sodium cromoglicate, or olopatadine hydrochloride as directed by a physician.

4. Bacterial keratitis: Infection of the cornea by bacteria such as *Staphylococcus aureus* causes sudden eye pain, photophobia, and blurred vision. Avoid touching the eyes with dirty hands. Use antibiotic eye drops such as levofloxacin, tobramycin, or chloramphenicol as prescribed. In severe cases, corneal debridement may be required to remove the infected tissue.

5. Acute angle-closure glaucoma: Sudden closure of the anterior chamber angle leads to a rapid increase in intraocular pressure, causing severe eye pain along with headache and nausea. Immediate medical attention is essential. Use intraocular pressure-lowering medications such as brinzolamide eye drops, timolol maleate eye drops, or pilocarpine eye drops as prescribed. Surgical intervention such as trabeculectomy may later be performed to establish a new aqueous humor drainage pathway.

Maintain good eye hygiene in daily life and avoid rubbing the eyes with unclean hands. Eat more foods rich in vitamin A, such as carrots and spinach, reduce intake of spicy and irritating foods, and promote overall eye health.