Laser surgery is a type of surgery that uses a laser to cut tissue or remove a surface lesion such as a skin tumour. There are a number of different types of lasers that differ in emitted light wavelengths and power ranges and in their ability to clot, cut, or vaporize tissue. The frequently used lasers are the YAG laser, the pulsed-dye laser, the argon laser, the CO2 laser, the exciter laser, the KTP laser, and the diode laser. Laser surgery is commonly used on the eye. Methods used include LASIK, which is used to correct near and far-sightedness in vision, and photorefractive keratectomy, a procedure which permanently reshapes the cornea using an exciter laser to remove a small amount of the human tissue.