1, there are certain misconceptions about keratoplasty treatment, such as the unrealistic belief that the method can cure myopia. 2, expectations are too high and do not match the actual role of keratomileusis. 3, eye disorders: such as patients with diseases of the ocular surface, epithelial cell degeneration, endothelial cell degeneration, cone corneas, patients with recurrent epithelial cell spotting and severe dry eyes, infection, inflammation, etc. 4, refractive error myopia greater than 600 degrees, astigmatism for the inverse gauge, astigmatism greater than -200 degrees is not suitable for night wear. 5, patients with significant intraocular astigmatism, as well as those with refractive irregularities myopia than astigmatism ratio less than 2 need to be considered carefully. 6.Patients with large pupils, especially those with large pupils at night 7.Patients younger than 7 years old, poor self-care ability and poor personal hygiene 8.Patients who cannot complete the follow-up operation, and those who have poor compliance with the fitting and follow-up 9.Patients whose intraocular pressure exceeds normal