Myopia surgery is usually referred to as keratoconus surgery. The following precautions need to be taken before surgery: First, active eye diseases such as keratitis and conjunctivitis should be ruled out. Serious systemic diseases such as diabetic patients, systemic connective tissue diseases, and immunocompromised patients should be operated with caution. Secondly, those with high expectations of surgery should be operated with caution. Third, the age should not be too young, generally requiring at least 18 years of age and a stable refractive state for more than 2 years. Fourth, the range of myopia treatment is generally within 1200 degrees of myopia, 600 degrees of astigmatism and 600 degrees of hyperopia. Fifth, the curvature of the cornea is generally required to be less than 48D, and the thickness of the cornea must be at least 460 microns. Sixth, the pupil diameter requirements are: patients with a generally large pupil diameter, such as more than 7mm in the darkroom, are recommended to be treated without surgery or with caution in order to avoid complications such as postoperative glare and night vision impairment.