The total refractive power of the eye is 58.64D, while the refractive power of the cornea is 43.05D, accounting for 70% of the total refractive power, and the cornea is located on the surface of the eye, making it easier to operate, so many scholars believe that surgery to correct refractive errors of the eye should first start with the cornea. Corneal refractive surgery is a surgical procedure to change the shape of the corneal surface to correct refractive errors, including myopia, hyperopia and astigmatism. The basic approach is to make different shaped incisions in the cornea to release the tension of the corneal fibers, such as radial keratotomy (RK), or to remove part of the corneal tissue by precise laser cutting to flatten or steepen the corneal surface, such as excimer laser refractive keratectomy (PRK) and excimer laser refractive keratectomy (ECL). (PRK) and excimer laser in situ keratomileusis (LASIK). As early as 1869, Herman Snellen, a Dutch ophthalmologist, reported that an incision in the steeper corneal meridian could alter the amount of astigmatism. Subsequently, in 1885, Schiotz in Norway reported that a corneal incision along a steeper meridian could result in a significant flattening of the cornea during cataract surgery. The first person to actually perform keratomileusis to treat myopia was Mitsuru Sato (1939) in Japan, who observed that myopic refraction decreased due to flattening of the cornea after Descemet’s membrane rupture occurred in conical corneas. Originally, an incision was made from the anterior surface of the cornea, but the results were not satisfactory because the central visual zone of the cornea was retained too large (>6 mm) and the depth of the incision was insufficient (only 50% of the corneal thickness). Since the important role of corneal endothelium in maintaining corneal transparency was not known at that time, the surgery was changed to incision from the anterior and posterior sides of the cornea. Due to severe damage to the corneal endothelium, large vesicular keratopathy occurred in 3/4 of the cases 10-20 years after surgery and led to blindness. This historical tragedy interrupted keratoconus research for some time. Another pioneer of keratomileusis was Barraquer in Spain, who in the 1950s and 1960s used keratomileusis and keratophakia to correct nearsightedness and farsightedness by altering corneal thickness and refraction. The former is to cut off the anterior corneal layer with a microkeratome, freeze it, and then use a special lathe to thin the central part (to correct myopia) or peripheral part (to correct hyperopia) spherically, and then sew it in place; while the latter is to cut open the corneal lamina, and then use an allogeneic human cornea or synthetic material to cut a convex or concave lens and sandwich it between the cut corneal lamina to correct hyperopia or myopia. However, these procedures have not been popularized because they are complicated, risky, unpredictable, and inevitably result in scar formation during interlaminar healing, which affects the optical outcome. Fyodorov (1972) in the former Soviet Union further developed and refined radial keratotomy, driven by ocular microsurgery. He proposed the important principles of modern RK surgery: (1) the smaller the preservation of the central visual area of the cornea, the greater the resulting refractive correction; the deeper the corneal incision depth, the greater the correction effect. Therefore, the current RK surgery generally preserves 3 mm of the central corneal visual field and the incision depth reaches 85% to 90% of the corneal thickness in order to obtain the maximum amount of correction. ②In order to avoid corneal endothelial loss of compensation, only radial incisions can be made on the corneal surface. (③According to the preoperative refractive error, the surgical volume is determined by a calculation formula to make the correction more precise. Bores (1978) in the United States further improved the RK preoperative examination equipment and surgical instruments, simplified the surgical calculation formula and standardized the surgical operation method. In the 1980s, hundreds of thousands of myopic correction RK surgeries were performed annually in the United States, which became the major myopic refractive surgery procedure at that time. Almost parallel to RK surgery is the surface keratoplasty (epikeratophakia) proposed by Kaufman (1980) in the United States, which has been carried out in the United States, the Soviet Union, the United Kingdom, France, Germany and other countries and has achieved certain results. Zhongshan Eye Center of Sun Yat-sen University in China (1990) also took the lead in clinical research and application in China. Surface keratoplasty is mainly used for the correction of hyperopia, especially for aphakic eyes. The introduction of the excimer laser revolutionized keratoconus surgery, and in 1983, Trokel et al. at Columbia University first reported the fine cutting effect of the excimer laser on the cornea of bovine eyes without thermal effects. Subsequently, in 1985, T. Seiler et al. in Germany used the excimer laser for the first time to perform keratomileusis on blind eyes to observe refractive changes based on animal experiments, and in 1988, Marguerite McDonald in the United States first used excimer laser refractive keratectomy (PRK) for The excimer laser has a wavelength of 193 nm and is used for the treatment of refractive errors. The excimer laser is a far-ultraviolet laser with a wavelength of 193 nm and an activated fluorine-argon (ArF) dimer as its working substance. Each photon has an energy of 6.4 eV, which is much greater than the energy required to maintain molecular bonds in corneal tissue (3.4 eV). When the excimer laser acts on the corneal tissue, it breaks it down into small fragments to produce a vaporization effect, also known as the cutting photolysis effect. Due to the short wavelength of the laser, in addition to the high photon energy, the penetration is weak (0.25mm per pulse), so the cutting edge of the tissue is neat and does not damage the surrounding tissue and has no effect on the intraocular tissue. Currently, there are three types of excimer laser machines, namely, large spot blast type, slit scan type and flying spot scan type. The advantages of the large spot (spot diameter >1.0mm) blast type are that the treatment time is shorter with a lower laser pulse frequency and the cutting is less likely to be off-center; the disadvantages are that the cutting surface is relatively rough, the incidence of central island is higher, and the acoustic vibration wave is larger. The advantage of scanning type is that the cutting surface is smoother, the incidence of central island is lower, and the acoustic vibration wave is smaller. The disadvantage is that it requires an eye tracking system, otherwise it is prone to off-centering; in addition, the treatment time is longer and the laser pulse frequency needs to be increased significantly. With the rise of wavefront-guided individualized excimer laser keratomileusis, small spot (spot diameter