Decreased vision is caused by the following: 1. Using the thickened lens and not taking off glasses to see objects at a short distance. 'Farther' environment should be created at a short distance. 2. Behaviors of watching bright light from electronic media. 3.Stress. Eyesight can be preserved only if the above factors are avoided. Eyesight recovery requires focusing on creating environment of high levels. Eyesight recovery is difficult with the naked eye, and can be successful by the aid of instruments. It is best to learn and practice the training; in daily life, it is helpful to try to see objects 1 m away lest the thickened lens be used. It is good to avoid short-distance life as far as possible, and the principle of 'farther' must be kept in a short distance.