The basic principle of excimer laser surgery: Excimer laser is a “cold laser”, which is an excited dimer laser that, under the control of a computer, precisely cuts the corneal tissue and changes the curvature of the cornea according to the refractive error to be corrected, in order to correct the vision. Excimer laser in situ keratomileusis is one of the most advanced procedures developed in recent years to treat myopia, and is particularly suitable for high myopia. LASIK, which is also used in eye centers, involves cutting a “corneal cap” of 0.16 mm in thickness on the corneal surface, turning it over, then cutting the corneal stroma with an excimer laser, and finally resetting the “cap” without sutures. No sutures are required. The advantages of laser surgery for refractive errors: 1, a wide range of applications: can correct myopia – within 15.00D; farsightedness, astigmatism within 5.00D; 2, high safety: no significant change in the mechanical strength of the cornea after surgery; 3, high accuracy: computer-controlled, the general error of about 1.00D; 4, surgery painless: local anesthesia, surgery time is only 10 minutes; 5, short surgery time The laser time is only a few tens of seconds to 1 minute; 6. Fast post-operative recovery: you can recover the next day after surgery and can go to work normally; 7. Stable effect: long-term refractive error is stable after surgery; 8. Indications for laser surgery patients: 1, age above 18 years old, vision stable for two years. 2, no eye inflammation, cone cornea, glaucoma, cataract, dry eye disease, and retinal disease, no history of larger eye surgery, such as glaucoma and net detachment surgery, etc. 3, 2 weeks for soft contact lens wearers, 4 weeks for hard contact lens wearers, and no complications caused by contact lens. 4.No serious systemic or local infectious or systemic diseases, such as hepatitis, cardiovascular and cerebrovascular diseases, etc., and no scarring body. 5.Patients who have the requirement of laser surgery and understand the principle of surgery and postoperative complications without excessive expectations.