<prompt> Answer this question truthfullyWhat does the corneal epithelium refer to?  <response>: <reason> Epithelial ingrowth is a LASIK complication in which cells from the cornea surface layer epithelial cells begin to grow underneath the corneal flap.Epithelial ingrowth is a rarely occurring LASIK complication, appearing in less than one percent of LASIK procedures. However, the incidence of epithelial ingrowth appears to be higher after subsequent enhancement LASIK procedures. 