I. Definition of excimer laser and the principle of surgery Excimer laser is a “cold laser” produced by fluorine and argon gas in an excited state, which is invisible to the naked eye. Excimer laser surgery is a high-tech means of treating myopia and is currently a very successful form of corneal refractive surgery. The principle is to use a computerized excimer laser beam to open the chemical bonds of tissue molecules through the energy of laser photons, causing the tissue to vaporize and play a cutting role, changing the curvature of the cornea, reshaping the curvature of the cornea, flattening the center of the anterior surface of the eye (flattening the curvature of the cornea), allowing light to focus on the retina, so that external light can accurately converge and image in the fundus of the eye, thus achieving the treatment of myopia, farsightedness and astigmatism. Farsightedness and astigmatism. Excimer laser treatment for myopia has the advantages and effects Excimer laser treatment for myopia has the characteristics of neat and clean cutting, high precision, strong prediction, good stability, and very few comorbidities, etc. Patients are painless during surgery, do not need to be hospitalized, and do not affect normal work and life, which is the ideal surgical solution for the treatment of myopia. The effect of laser treatment for myopia is long-lasting and stable. For myopic patients with more than 1000 degrees of myopia, it is basically not easy to regress after surgery. This is because the surgery for patients with advanced myopia is usually slightly more corrective according to the degree of myopia. Due to the correct estimation in advance, even if regression occurs in a year or two, the correction is just right. The regression and re-wear of glasses in individual patients is due to their own physical condition, eye condition and improper post-operative maintenance. It should be emphasized that post-operative care should be taken to protect the vision and adhere to healthy eye use. Excimer laser treatment for myopia is a computer-controlled, accurate cutting of the anterior corneal layer to reduce refractive error for the purpose of myopia correction, and the procedure has no effect on the surrounding tissues and deep intraocular structures. Objectively speaking, the safety of the current excimer laser surgery is relatively high, compared with the earliest myopic radial keratotomy surgery using a diamond knife, its safety has taken a qualitative leap, after more than 10 years of extensive clinical practice has fully proved this, it can be said that the laser treatment of myopia surgery in China has been relatively mature. However, the success rate of any surgery cannot be 100%, just as contact lenses are prone to infection that endangers vision, and trauma caused by ruptured lenses of frame glasses is also a cause of blindness. Most refractive surgery experts in China disagree with the American Journal of Ophthalmology article that states that the failure rate of such eye surgery is 1/10. Of course, good surgical equipment, skillful operation and experience of the surgeon, and good cooperation of the patient are the basis of high safety of the surgery.