Edema in one eye and normal in the other eye is usually caused by allergic factors, infectious factors, mechanical stimulation and so on. Allergy is a common cause of monocular edema, usually accompanied by eye itching and other manifestations, can be treated with anti-allergy drugs such as olopatadine hydrochloride eye drops, and at the same time to keep away from allergens. Infections can also lead to monocular edema, such as bacterial conjunctivitis, granuloma, etc., usually need to be treated with antibiotics, such as coated with ofloxacin eye ointment. Mechanical stimuli such as rubbing the eye can also cause edema, which can be reduced by applying cold compresses and avoiding undesirable behaviors such as rubbing the eye. If the edema in one eye does not subside for a long time or is accompanied by eye discomfort, it is recommended to consult a doctor for treatment. Medications should be used under the guidance of a doctor, do not take medication without authorization.