Swollen eyes may be caused by physiological or pathological factors, common causes include improper living habits, mosquito bites, allergies, infections and so on. 1. Improper living habits: rubbing the eyes, staying up late, improper diet and other physiological factors may cause the patient’s eyes to appear swollen, generally can be recovered on their own. 2. Mosquito bites: mosquito bites on the eyelids can cause swelling on one side of the eyes. 3. Eye allergy: patients with eye allergy, patients may experience eye swelling, itching and other uncomfortable symptoms. 4. Eye infections: Eye infections are also a common pathologic factor that causes eye swelling in patients. Patients with eye diseases such as mydriasis, dacryoadenitis, and other eye diseases can experience eye swelling under the stimulation of inflammation. It is recommended that patients with abnormal eye swelling consult a doctor in time to assess their condition and follow the doctor’s instructions for treatment.