When it comes to vision, the first thing that comes to mind is vision, but in fact, vision has much more than that. The basic functions of human vision are light perception, shape perception, color perception, eye movement, binocular monocularity, and other physiological functions. The basis of vision is photoreception, the perception of external light stimulation is the most basic feature of vision. In addition to photoreception, the eye also has morphological perception, which is the ability to distinguish and recognize the shape of external objects, also known as central vision or visual acuity. Corresponding to the concept of central visual acuity, the spatial extent of the eye is called the visual field when the eye is fixed in front of a target, and the finer the resolution of objects in the visual field toward the periphery, the worse it is. In addition. The human eye can distinguish about 150 shades of more than 13,000 colors from the visible spectrum of nature, and this ability is called color vision. While the above are the capabilities of each of our eyes, one of the visual capabilities that distinguish humans from many animals is that we also have very good binocular vision. Binocular vision is divided into three levels: the most elementary is simultaneous perception, that is, both eyes can see two different images at the same time; the second level is like fusion function, that is, both eyes will be two mostly identical, in the details of some differences in the image into one image; the third level is stereo vision, for three-dimensional space perception, also known as depth perception or spatial vision, with perfect binocular vision, in order to perceive the three-dimensional shape of the object and the object and The distance between the object and the human eye, or the relative distance of two objects. Stereopsis is the highest level of binocular monocularity, the basis for all kinds of advanced fine work. Normal vision is not only related to whether we can see clearly or not, which affects the quality of human life, but also directly related to the development of human intelligence and thinking. The richer the external stimulation received through the sensory system, the faster the development of the cerebral cortex. More than 80% of our perception of the outside world is obtained through the visual system. But human vision is not innate. Newborns are born with only photopic reactions, and their visual function is gradually developed and perfected after receiving a large number of visual stimuli after birth. Visual development continues until the age of 12-13 years, which is the sensitive period for visual development, the most critical period being the first 2 years of life, during which the ability to receive a large number of visual stimuli is necessary for visual development. Deprivation of visual stimulation of the eye by external light for any reason can seriously affect visual development and produce amblyopia. Also, it is only by seizing this period to treat various diseases that cause delayed visual development that normal visual ability can be achieved. Therefore, it is important to seize the opportunity for early intervention and treatment of eye diseases in infants and children.