The higher the degree of myopia, the more corneal tissue must be removed during the operation. In order to ensure the stability of the cornea, corneal thickness should be maintained at at least 280 microns (µm) to avoid Keratoconus. The professional physician will complete a visual assessment to judge whether surgery is suitable. Regardless of whether or not surgery is performed, patients with high degrees of myopia are recommended to perform regular retinal examinations.