Patients presenting with unilateral eye swelling may be caused by ocular trauma, mosquito bites or blepharitis. 1. Eye trauma: If the patient accidentally hit the unilateral eye socket, without timely cold compresses on the damaged blood vessels and hemostasis, resulting in subcutaneous hemorrhage, unilateral eye swelling can occur. Patients can apply cold compresses to reduce bleeding in the early stage of eye trauma, and local hot compresses can be applied after 48 hours to promote blood circulation and reduce edema. 2. Mosquito bites: If the patient’s eyes are bitten by mosquitoes, it can cause an allergic reaction, resulting in the patient’s eyes appearing localized redness, swelling, itching and other uncomfortable symptoms. 3. Blepharitis: Blepharitis refers to suppurative inflammation of the eyelid glands, mostly caused by Staphylococcus aureus and other bacterial infections, and under the stimulation of inflammation, the patient may experience unilateral eyelid edema, pain and other uncomfortable symptoms. It is recommended that patients with significant eye swelling should seek prompt medical attention to assess their condition and follow the doctor’s instructions for treatment.