There is usually no change. However, patients whose original myopia is in an unstable state where it continues to progress will develop new myopia after surgery, because surgery can only correct the current myopia and cannot stop the progression of myopia. Therefore, there is a prerequisite for patients to undergo surgery, which requires that the refractive error be stable for at least 2 years. Because of the differences in corneal healing after surgery, individual patients may experience partial regression after surgery, and even if they do, it is unlikely that they will regress to their original original diopters. If there is a large regression, a retrospective can be done for free if allowed.