There are many reasons for pain in one eye, such as glaucoma, uveitis or keratitis, etc. It is necessary to consult a doctor in time to find out the cause of the disease and then carry out targeted treatment. 1. Glaucoma: Patients with glaucoma will experience eye pain due to the obstruction of aqueous drainage. They need to consult a doctor in time and apply medication such as brinzolamide drops or surgery such as trabeculotomy to control the eye pressure, thus relieving the symptoms and minimizing the damage to the optic nerve. 2. Uveitis: in addition to the symptoms of eye pain, it may also be accompanied by eye redness, photophobia, tearing and other discomforts, which need to be treated with ciliary muscle paralyzing agents, glucocorticoid drugs, etc., in order to control the inflammation and reduce the complications. 3. Keratitis: when keratitis occurs, the symptoms of corneal pain are obvious, if it is caused by bacterial infection, it can be treated with tobramycin dexamethasone eye drops, if it is caused by viral infection, it can be treated with antiviral drugs such as acyclovir eye drops. The causes of monocular pain are varied, persistent unrelieved or even lead to vision loss need to be vigilant, it is recommended to consult an ophthalmologist in a timely manner, the measurement of intraocular pressure, slit-lamp microscopy and other ancillary tests to confirm the diagnosis, standardized treatment under the guidance of the doctor, the use of medication, do not use their own medication.