The US Food and Drug Administration recently approved the 193-nm excimer laser for the treatment of superficial corneal pathology and surface irregularities--a procedure called phototherapeutic keratectomy (PTK). Indications for PTK include corneal dystrophies, degenerations, and scars that impair corneal transparency, thus compromising visual acuity. In some cases, PTK may offer a better treatment modality than corneal transplant surgery. This article reviews the basic fundamentals of PTK, including indications for surgery, the surgical procedure, preoperative and postoperative patient evaluation and care, and possible complications.