Why does my vision suddenly drop after looking at my phone continuously for a long time? There are three possible reasons for this to happen. One is sudden overuse of the eyes, causing a spasm of eye adjustment. When people look at things, they need the ciliary muscle in the eye to contract to make adjustments. If you use your eyes excessively for a long time, the muscle cannot relax, and distant objects become blurry. The second reason is to use the eyes in a dark environment for a long time, which causes damage to the surface of the eyes and may even lead to tears, fear of light and shame of the eyes. The third reason is that when a person looks at something exciting, or is in a particularly tense or excited state, it may cause spasm and constriction of blood vessels, resulting in transient ischemia of the eyes. The so-called blindness, in terms of ophthalmology, is actually the absence of light perception, it may be a sudden loss of vision, we understand it as blindness. The most likely symptom of prolonged nighttime cell phone watching is dry eye. The eyes need to secrete a certain amount of tears, and they cannot evaporate too fast. If a person stares at the phone for a long time, the number of blinks will be reduced and the tears will evaporate excessively, which will cause the epithelium of the cornea to peel off. This causes the person to feel uncomfortable and dry eyes, and even the feeling of entering a foreign body, and the vision will be reduced. In addition, looking at something with a small screen like a cell phone in the dark for a long time can stimulate glaucoma. It may also cause spasm of blood vessels or cause the eyes to be unable to relax and the adjustment power to decrease. At the age of 40 to 45, the decrease of eye regulation will be more obvious. In addition, as age increases, the secretion function of the tear glands or the health of the tear film on the eye surface decreases, so it is more important for middle-aged people to pay attention. It is important to prevent eye diseases. Don’t wait until you have symptoms to start paying attention to them, but start to prevent them from the beginning, look at cell phones and computers in moderation, pay attention to time control, not continuously look at more than an hour, an hour is best to close your eyes and relax for three to five minutes, or look at the distance to adjust. Another is to choose the right font size and lighting intensity. The first thing you should do is to pay attention to rest when you look at the phone for a long time at night causing eye discomfort. When the eyes are dry and uncomfortable to immediately rest, if rest for a period of time, eye discomfort or blurred symptoms still can not be relieved, then we must go to the hospital. In addition, you can also make some adjustments in the diet structure, for example, you can take some vitamins orally, especially vitamin A. Eat more carrots and fresh vegetables. When you wash your face, you can use a hot towel on your eyelids and then do some gentle massage near the eyelashes to keep the lid glands secreting oil smoothly, this oil can protect the aqueous component of the eyes from evaporating too fast.