The anterior and posterior diameters of the eye are too long, which is a manifestation of a long eye axis. This condition is usually seen in myopia, and as myopia deepens, the length of the eye changes, and the higher the degree of myopia, the longer the length of the eye axis. In other words, there is no way to restore the shape of the eye to normal. When the length of the eye axis reaches a certain level, there will be highly myopic fundus lesions, such as vitreous opacity, vitreous liquefaction, retinal fissure, retinal detachment or macular hemorrhage, macular cleft, all of these complications will have a serious impact on vision. In order to avoid this situation, we must pay attention to control the growth rate of myopia in general.