Unilateral eye swelling may be caused by unilateral eye inflammation, eye allergy, trauma and other reasons. 1. Unilateral eye inflammation: such as unilateral eye chalazion, conjunctivitis, keratitis, ciliary body inflammation, choroiditis, total uveitis, etc., due to the inflammation stimulation, it is easy to cause the eye loose connective tissue edema, eyelid swelling. 2. Unilateral eye allergy: most common in seasonal allergic conjunctivitis, mainly due to pollen and other allergens. 3. Unilateral eye trauma: such as eyelid scratches, eyelid injuries, etc., can also cause unilateral eyelid swelling. In addition to the above diseases, cardiac insufficiency, diabetic peripheral neuropathy, liver and renal insufficiency and other diseases can also cause the above symptoms. If the above symptoms occur, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment.