The length of the axis of the eye changes with age, and the axis of the newborn is 17.5mm. As the eye grows and develops, the normal length of the eye reaches that of an adult after the age of 6, which is about 24mm, and the visual acuity develops to about 1.0 for a normal person. Therefore, every child’s eye is basically highly hyperopic at birth, and gradually tends to develop in the direction of myopia as the eye grows and the eye axis grows. For every 1mm increase in axis length, myopia increases by 300 degrees. This growth is irreversible, just like a person who grows taller and can’t go back. Myopia also cannot be recovered at present, and it becomes true myopia.