Eyes will tear when looking at the cell phone in the exclusion of foreign body influence, often consider several situations, respectively, visual fatigue, dry eye, keratitis, and so on. 1. Visual fatigue: the luminous range of the cell phone screen is very limited, and the degree of light is low, the eyes will cause eye fatigue after a long time looking at the phone, the eyes will be compensatory secretion of tears to reduce fatigue, usually try to reduce the time and number of times looking at the phone. 2. Dry eye: staring at the cell phone for a long time will lead to a reduction in the number of blinking, so that the excessive evaporation of tears, easy to cause dry eye, dry eye after the basic tears will be insufficient to stimulate the tear reflex secretion, which often tears. 3. Keratitis: the most common cause is infection, keratitis will lead to corneal infiltration foci, looking at the cell phone will make the cornea stimulated, so that tears and even pain. If the symptom of tears when looking at a cell phone persists and cannot be relieved, it is recommended to consult a doctor to avoid aggravation of the condition.