Circumstances in which the eye cannot undergo myopic surgery may include: concomitant eye diseases other than myopia, unstable refractive status, myopia that is too high or too low, and pupil diameter that is too large. In addition, systemic diseases such as hyperthyroidism, diabetes mellitus and scarring are not suitable for myopic surgery. 1. In addition to myopia accompanied by other eye diseases: such as external eye infection, cone cornea, high intraocular pressure, dry eye, etc. can not do myopic surgery, which is likely to cause the spread of infection to the eye, corneal rupture or dry eye aggravation. 2. Unstable refractive state: It is not recommended to do myopic surgery if you are under 18 years old or if your myopia has increased by more than 50 diopters per year in the past 2 years, and your refractive error may continue to increase after the surgery. 3. Myopia too high or too low: myopia within the range of 100-1200 degrees can be myopic surgery, too low a degree of surgery is not necessary, too high a degree of intraocular lens implantation surgery can be considered. 4. Pupil diameter is too large: for myopic patients with pupil diameter more than 7mm in the dark room, night vision disorder and glare are easy to appear after the operation, generally surgery is not recommended, and patients should be informed of the corresponding surgical risks if they want to have the operation. 5. Systemic diseases: such as uncontrolled diabetes mellitus, systemic connective tissue disease and severe autoimmune diseases, etc., scarring due to slow wound healing, after cutting the cornea cornea is also more likely to form irregularities, or scarring of the healing, so can not do myopia surgical treatment. It is recommended that myopic patients should consult a doctor for a comprehensive examination to determine whether they are suitable for surgical treatment.