1. Pregnancy As early as the mother’s fourth week of pregnancy, the fetus’ vision is formed. At this time, the fetal eye is small (smaller than the head of a pin) and is enveloped by a cortex. In the next 4 or 5 months, the eye meridian, blood vessels, lens and retina begin to develop. By the end of the 6th month, the fetal eye has developed considerably. 2. Newborns Although the two eyeballs of normal newborns are formed, their vision is not fully developed. It is generally estimated that the vision between birth and 1 week is 0.01~0.02, and 0.05~0.1 for one-month-old infants. between birth and 3 months, the eyes do not fixate, but are attracted to faces, bright or moving objects. Therefore, they sometimes have a “strabismic” appearance. 3. 3 Months By this time, most infants can “follow” moving objects smoothly and can fix their eyes on an object. Colors and moving objects are attractive to infants, and these promote visual development. 4. 3~6 months During this period, the retina is well developed. Infants can see from near to far and then from far to near, and they can see subtle parts of objects clearly. Stereoscopic vision begins to develop at 4 months of age. 5, 6 months By this time, the eyes are about 2/3 of the size of an adult. When looking at objects, both eyes are seeing at the same time, thus obtaining normal “binocular vision”. The ability to judge distance and depth also continues to develop. 6. 1 year old At this time, the child’s vision is further developed in all aspects. The coordination of the eyes, hands, and body is more natural. Vision at this time is about 0.1~0.3. Before the age of 1, vision is “plastic”, and if vision is blocked, vision will not continue to develop, or even degrade. 7. 2~4 years old At this time, children like to look at pictures, drawings and stories with pictures often attract children’s attention, the normal visual acuity at the age of 3 is about 0.6~0.7, and at the age of 4, the normal visual acuity is about 0.8~1.0. The establishment of stereo vision at the age of 3 is nearly complete. 8. 5~7 years old The normal visual acuity at this age should be 1.0. if normal visual acuity cannot be achieved, the cause needs to be identified. If amblyopia is found, good results will be achieved through active treatment. 9. 8~9 years old The development of vision is basically completed. If amblyopia or lack of stereo vision is found only at this time, the chance of correction is not optimistic.