Corneal shaping lenses are a non-traumatic vision correction method for patients with myopia. The principle is that by wearing high oxygen permeable hard contact lenses and wearing them at night and taking them in the morning, the following results can be achieved in a short period of time 1. By wearing keratoplasty lenses at night, the damage to the eyes caused by traditional soft contact lenses is avoided because of their high oxygen permeability, high biocompatibility and anti-precipitation properties. 2, There is no need to wear glasses during the day, which will not affect the patient’s normal study, work and learning requirements. 3.While eliminating the trouble of frame glasses, it can effectively control the deepening of myopia in teenagers. In 1962, an optometrist was amazed to find that the wearer could slightly reduce the degree of myopia by mistakenly wearing a rigid corneal contact lens with a curvature flatter than his own, thus improving his vision without glasses. The main reasons for the failure of the first generation design to be clinically popular are: ① The use of PMMA material, which is not breathable, cannot be worn for a long time, and can only be worn for a short period of time during the day, so the effect is short-lived. Patients needed to wear a series of gradual flattening ordinary hard contact lenses during the day in order to obtain a certain degree of improvement in naked eye vision after removal of the lenses. It is poorly centered and tends to deviate up and down, causing astigmatism. In 1971, the second generation of plastic lenses was designed, the most important feature of which was the “reversed geometry”, the three-zone design, the base arc of the lens was 1.5-4.0D flatter than the central cornea, which improved the centering of the lens compared to the first generation and greatly shortened the treatment time. The shortcomings of this design are: ① The wide reversal arc and the large amount of edge warping in the second generation design cause irregular lens movement, and it is still difficult to maintain good lens positioning and neutrality. This design usually requires more than one pair to achieve the final orthodontic effect. This gradual reduction of myopia using 4-5 pairs of lenses is intended to control the central positioning. The treatment period is eventually reduced by 2-3D myopia. The 3rd generation emerged around 1995, featuring a design of the inner surface of the lens with more than 4 curved surfaces, as well as the use of high oxygen permeable lens materials, making it possible to wear the lenses only at night, without the need for regular replacement of multiple pairs of lenses, and correcting myopia up to a maximum of 600 degrees. The materials of keratoconus are classified by DK value as low oxygen permeability (DK value <50), medium oxygen permeability (DK value between 50 and 90) and high oxygen permeability (DK value >90) materials. The U.S. FDA requires that the DK value for night-wear lenses be no less than 80, and the Chinese SFDA requires that the DK value for night-wear lenses be no less than 90. Corneal shaping lenses are used to treat myopia by using specially designed corneal shaping lenses that symmetrically and progressively change the shape of the central surface of the cornea to reduce myopia; similar to laser surgery, but different from Unlike laser surgery, keratoplasty produces temporary and reversible results. -It has the effect of limiting the growth of myopia because it does not produce defocusing and has high quality imaging. Wearing method: Wear at night and remove during the day, and wear for no more than 10 hours continuously. Generally need to wear for 2 weeks to achieve stable effect. After 30 days of discontinuation of wear, the original condition is completely restored. The keratoplasty lens needs to be removed daily, which is a tedious and time-consuming process, and with the rebound of the cornea, the correction effect in the afternoon is worse than in the morning. In order to solve the above troubles, foreign countries are developing a biological curing agent, which is expected to be worn only a few times a month, or only a few times a year, and this curing agent is currently in clinical trials.