Abstract: when they go to the hospital for preoperative examination of myopia surgery, the medical staff will ask whether they have worn contact lenses and how long they have worn them, and then remind the friends who wear contact lenses to stop wearing them for a certain time before seeing a doctor for examination. Why must we stop wearing contact lenses before myopia surgery? This is the question of many patients., When you go to the hospital for preoperative examination of myopia surgery, the medical staff will ask whether you have worn contact lenses and how long you have worn them, and then remind friends who wear contact lenses to stop wearing them for a certain period of time before seeing a doctor for examination. Why must we stop wearing contact lenses before myopia surgery? This is the question of many patients. Stopping wearing contact lenses is one of the scientific procedures for myopia surgery. Experts say, Corneal contact lens (contact lens) the degree of influence on corneal morphology and diopter varies from person to person. According to age and other differences, the stopping time may be different, depending on the specific situation. The purpose of stopping wearing contact lenses: 1. Fully restore the original shape of the cornea, so as not to affect the preoperative diopter examination, so as to affect the accuracy of surgical correction 2. Different types of corneal contact lenses (different materials, different radians, matching degree with corneal shape) and the effect of corneal contact lenses on corneal tissue (thickness, elasticity, etc.) have different degrees of influence. 3. Generally, the easily deformed cornea is also easy to restore the shape before wearing. However, this kind of cornea should be paid attention to. Most of them are thin cornea or have the characteristics of keratoconus. 4. Stopping wearing contact lenses is to restore the normal corneal epithelial cells, especially the damaged corneal epithelial cells 5. If keratitis is caused by contact lenses, it needs systematic treatment. After keratitis is completely controlled, the operation can be carried out only after inspection and confirmation. Therefore, contact lenses should be stopped before the examination and evaluation of laser corneal refractive surgery. According to the current clinical practice experience, According to the type of lens (daily polishing, weekly polishing, monthly polishing, seasonal polishing and annual polishing) and wearing habits (occasional wearing and frequent wearing) and time, the soft contact lenses shall be stopped for at least 3 days to 2 weeks, with an average of more than one week. While the hard contact lenses (corneal shaping lenses or RGP) shall be stopped for at least 3 months, and the operation can be carried out only after the cornea returns to its original shape and the examination results are normal.