1. The need to improve visual acuity. High astigmatism is the most common cause of amblyopia, but the corrective ability of frame glasses is limited, and the “deformation” is obvious. After wearing RGP contact lenses, due to the formation of a unique tear lens between the lens and the glasses, vision correction is good, and the patient has a high degree of comfort; 2. Balance between the two eyes, the development of stereoscopic needs. The difference between the refractive errors of both eyes is more than 250 degrees, and the difference in the size of the object image after correction by wearing frames is more than 5%, which will hinder the formation of stereoscopic vision. However, wearing “contact lenses” can avoid the above phenomenon; 3. The need to control the rapid development of myopia. Keratoplasty is a kind of special contact lenses worn at night, which is currently a more effective means of controlling myopia.