A 4.0 vision is equivalent to a 0.1 vision, which is about 300 degrees. Usually this degree of myopia is already considered moderate myopia, so it has a greater impact on vision. Especially among children, if they have 300 degrees of myopia, they definitely need to wear glasses and need to monitor the growth of myopia every six months. If the growth is fast, you may also need to wear keratoplasty lenses to slow down the growth of myopia. In adults, there are many options, including frames, contact lenses, and myopia surgery. Usually laser correction of the cornea can be done for this type of myopia, and the post-operative results are good.