There are three levels of myopia depending on the severity: the first is mild myopia, which usually refers to myopia up to and including 300 degrees; the second is moderate myopia, which refers to myopia between 325 and 600 degrees; and the third is high myopia, which usually refers to myopia over 600 degrees. This classification criteria is mainly to highlight the serious degree of myopia on the eye damage size, because mild and moderate myopia will only cause vision loss, will not appear other pathological changes, high myopia is different, high myopia will appear high myopic fundus lesions, serious and even retinal fissures, retinal detachment these, so must pay attention to.