Swollen and painful eyes may be related to trauma, or due to insect bite dermatitis, eye inflammation and other causes. 1. Trauma: when the eye is hit or struck by an external force, resulting in trauma to the eye, it can cause the eye swollen and painful, and may also be accompanied by localized bruising and other symptoms. 2. Insect bite dermatitis: If the mosquito bites into the eye accidentally, it will induce insect bite dermatitis, which can cause eye swelling and pain, and can be accompanied by obvious itching and other symptoms. 3. Eye inflammation: when there are bacteria and other pathogens in the eye infection, under the stimulating effect of inflammation, can cause eye swelling and pain, can also be accompanied by eye foreign body sensation, photophobia, tearing and other symptoms. Common diseases include keratitis, conjunctivitis, blepharitis and blepharitis. If the symptoms are not relieved, you should go to the hospital to diagnose the cause of the swelling and pain, and then go to the doctor for treatment.