The length of the eye axis varies with age, typically being about 16 mm at birth and developing and stabilizing at about 24 mm in adulthood. The length of the eye axis is not fixed and grows with age and development. At birth, the axial length is the shortest, at around 16 millimeters, and then lengthens rapidly as it grows, reaching close to 20 millimeters by the age of six or seven. The rate of development then slows down, but still lengthens year by year until around 18 years of age, when it reaches around 24 mm and stabilizes. If the eye axis grows too fast, it may cause myopia. Usually, an increase in the length of the eye axis of more than 1 millimeter over the normal value will lead to an increase in myopia of 300 degrees. It is recommended that patients with abnormal eye axes seek prompt medical attention to evaluate their condition and follow the doctor’s instructions for treatment.