Eyes with more than 25 degrees of nearsightedness are considered myopic. According to the diopter classification of myopia, myopia is classified as low myopia, -0.25D to -3.00D, moderate myopia, -3.25D to -6.00D and high myopia, 6.00D or more. In general, myopia, mild to moderate is mostly simple myopia. Ultra-high myopia is pathological myopia. Since adolescent children, the ciliary muscle is often in a state of low contraction, so it is not a loss of vision, ordinary optometry, found to have a degree of myopia, is true myopia. Usually, it is necessary to adjust the numbing eye drops used after the dilated pupil examination to make a clear diagnosis. In recent years, studies have found that the occurrence of transient hypermetropia can occur after a period of continuous near looking, averaging -0.5D and lasting 1 to 2 minutes. Therefore, it is now also possible to determine, in conjunction with an examination of the eye axis length, whether it is true myopia. The normal population should have an eye axis of 24 mm, and if it is greater than 24 mm, true myopia is still usually considered. Therefore, if true myopia is diagnosed, it is best to wear glasses to correct it in a timely manner. If teenagers and children, they can consider the treatment of keratoplasty, and if adults, they do not want to wear glasses, they can consider myopia surgery.