Eye strain may be caused by visual fatigue, corneal conjunctival dryness or conjunctivitis. 1. Visual fatigue: prolonged reading or use of electronic products (such as computers, cell phones, etc.) can cause visual fatigue, astringent eye fatigue, which may be accompanied by eye distension, eye foreign body sensation and other uncomfortable symptoms. You should pay attention to rest, relieve eye fatigue, avoid excessive eye use. 2. Corneoconjunctival dryness: dry eye, often manifested as dry eyes, foreign body sensation, blurred vision and visual fatigue, etc. Mild dry eye does not affect or mildly affect vision, and in the late stage, corneal limbal epithelial cell dysfunction can occur, which seriously affects vision. 3. Conjunctivitis: Bacteria, viruses, smoke and dust can cause conjunctivitis, the common symptoms of foreign body sensation, burning sensation, itching, photophobia, tearing, etc., but also can appear in the eyes, eye soreness, visual fatigue and other symptoms. When there is eye astringency and eye fatigue, it is recommended to go to the ophthalmology department of the regular hospital, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.