Myopia can be divided into low myopia of less than 300 degrees, moderate myopia of 300-600 degrees, and high myopia of more than 600 degrees. 400 degrees of myopia belongs to the category of moderate myopia by degrees. 400 degrees of myopia is not a very high degree of myopia, corrective measures include the following: first of all, the safest and most effective is still optometry. It is important to note that if you are less than 16 years of age and children, you need to take a dilated optometry to get an accurate prescription, and after the optometry you can consider wearing frame glasses and contact lenses. In addition, surgical treatment is also available, which includes laser surgery and IOL implantation for crystalline eyes.