Amblyopia can be commonly understood as a delay in the development of vision, which means that the vision is not fully developed for various reasons during the development of vision. Here, it is necessary to first understand the process of understanding the normal development of vision. So, what is the world like for the growing baby? The world in the eyes of the baby: 4 weeks of pregnancy, the fetal eye began to develop, the anatomical structure of the eye began to gradually develop and differentiate; 15 weeks of pregnancy, the fetus can feel the light, at this time with light stimulation, the fetus may have a corresponding response; 27 weeks of pregnancy, the fetus can already open and close the eyes, 30 weeks of pregnancy, the baby can already distinguish between light and darkness, and even back and forth to find the light source. Is the baby was born, he saw the world and adults see is not the same: born within 1 month of the baby can see the object in front of 15-30 cm, gradually began to be able to gaze at the object, but both eyes can not be well coordinated gaze, the little one at this time like soft light, if the stronger light shining eyes, the baby will quickly close their eyes. At 2 months old, they like to look at moving objects and familiar faces, and when an object comes quickly near their eyes, they will blink and other protective reflexes, and they can look at their small hands for more than 5 seconds. At 3 months old, babies can see about 75cm away and have a visual acuity of about 0.1. The gaze time is significantly longer and the eyesight can follow moving objects. For example, the baby’s eyes will follow the mother’s body movement and turn. Babies are very sensitive to colors at this time and prefer to look at bright and vivid colors, especially red, and not dull colors. Their preferred colors in order of red, yellow, green, orange, blue, etc. At this time, you can often tease the baby with red toys and observe whether the baby’s eyes will be interested. (Cartoon: 21, swaddled baby, I like red, remember oh) 5-6 months can accurately see the front of the object, but also can grab the object in front of the eyes to play, hand-eye coordination, but also can look at more distant objects, such as street pedestrians, vehicles, etc.. At this point, you can use toys to move slowly up and down, observe whether the baby can consciously take the initiative to follow, and judge the assessment of the baby’s eyesight. One-year-old babies can follow falling objects, look for dropped toys, and be able to distinguish the size, shape and speed of movement of objects. Beginning to appear depth perception, which is actually a three-dimensional sensory perception, visual acuity of up to 0.2. 2-3 years, visual acuity of about 0.5-0.6; 4, 5 years, some children’s visual acuity can reach about 1.0, a variety of eye physiological reflexes have been formed and tend to stabilize; 6, 7 years to reach the level of adult vision (Table 1 baby age and visual acuity).