Our eye movements are performed by three pairs of cranial nerves controlling six pairs of twelve muscles in both eyes. When the eyes move in concert with the brain, good binocular vision, including spatial perception (stereopsis) and spatial orientation, is developed to adapt to a variety of living and working environments. Once the movement of both eyes is out of balance, one eye will focus on the target while the other is off the target, and binocular vision will be disrupted, which is called strabismus. According to the direction of the skewed vision, strabismus is often divided into internal strabismus, external strabismus and vertical strabismus. Prevention points: 1. Prevention of strabismus should start from infancy, parents should pay attention to carefully observe the development and changes of their children’s eyes. Parents should pay attention to the coordinated function of both eyes and observe the eye position for any abnormalities. 3.The child’s eye hygiene or eye hygiene should be paid attention to frequently. For example, lighting should be appropriate, not too strong or too weak, printing pictures with clear handwriting, do not lie down to read books, do not watch TV and play video games and computers for a long time, do not look at 3D pictures, etc. 4. For children with a family history of strabismus, even though there is no strabismus in appearance, it is necessary to ask the ophthalmologist to check at the age of 2 weeks to see if there is farsightedness or astigmatism. 5. When children watch TV, in addition to maintaining a certain distance, children should not be allowed to sit in the same position every time, especially the position of the oblique to the TV. Should always exchange seats left and right, otherwise the child in order to watch TV, the eyes always look in one direction, the head will also be habitually crooked to one side. Over time, the development and tension of the six eye muscles will be different, losing their original role in regulating balance, and one side of the muscle will always be in a state of tension, while the other side will be relaxed, resulting in strabismus.