Tears are not only a common ophthalmic symptom, but also a common ophthalmic disease that can cause tears, the following are common: first, due to tear duct obstruction or narrowing, the tear duct is located in the inner corner of the eye, connecting the conjunctival sac and the nasal cavity, the main role is to discharge the tears secreted by the eye into the nasal cavity, absorbed by the nasal mucosa, once the tear duct is narrowed or obstructed, so that tears accumulate in the eye to form a tearful performance. The diagnosis can be confirmed by tear duct irrigation, and if the tear duct is obstructed or narrowed, it can be treated by tear duct exploration. Second, due to ingrown eyelashes or entropion, the eyelid entropion or ingrown eyelashes can cause the eyelashes to lodge against the cornea, thus damaging the cornea and causing reflex tearing, which needs to be removed, electrolyzed or surgically corrected to cure the entropion. Third, due to keratitis, when the cornea is inflamed, it can cause corneal tingling and other symptoms, resulting in irritated tearing.