PTK (Photo Therapeutic Keratectomy) is used to treat corneal surface diseases and shallow corneal scars. PTK's goal is to produce a smoother and clearer cornea through "polishing" the cornea.

The epithelium, a layer of cells covering the cornea, is gently removed and the laser is applied to the corneal surface.  

PTK can sometimes be combined with PRK if a refractive error is also present.