Swelling of the left eye may be caused by visual fatigue, glaucoma, trauma and other factors, the patient should consult a doctor in a timely manner, under the guidance of the doctor for appropriate treatment. 1. Visual fatigue: If you have stared at the computer, cell phone or TV for a long time before the swelling of your left eye, and you are in a place with poor lighting, you should consider that the swelling is caused by visual fatigue, and this kind of patients will also suffer from dry eyes, blurred vision, and loss of visual acuity. In this case, you should pay attention to rest, reduce the time of using electronic devices, and if necessary, use artificial tears, such as sodium vitrate eye drops to relieve symptoms. 2. Glaucoma: progressive optic nerve damage and visual field defect caused by increased intraocular pressure, patients will have symptoms such as eye swelling, blurred vision, headache and night blindness on the side of the glaucoma occurring, including the appearance of eye swelling, and in acute episodes, you can use hairy fruit rutaecarpine drops, and if necessary, laser. 3. Trauma: If the patient has a history of trauma to the head and face or obvious skin lesions around the eyes before the occurrence of eye swelling, eye swelling caused by trauma should be considered and treated under the guidance of a doctor. Swelling of the left eye, after resting the symptoms can not be relieved, and accompanied by other discomforts, timely medical treatment, under the guidance of the doctor to use medication.