There is a trend in the growth of the eye axis. When a normal child is first born, the length of the eye axis is around 16mm. From birth to 2 years of age, the growth rate of the eye axis is about 0.6mm; between 3-10 years of age, the growth rate of the eye axis is 0.5mm; between 10-12 years of age, the growth rate of the eye axis is between 0.5-0.6mm; between this 12-18 years of age, the growth rate of the eye axis is between 0.3-0.4mm. After the age of 18, the growth gradually stops and basically stabilizes by the age of 20. The normal human eye axis is stable by the age of 20, and the eye axis fluctuates around 24mm, which is a normal value. If the growth rate is too fast and exceeds 24mm, for every 1mm increase in the eye axis, the myopia increases by about 300 degrees.