The Excimer Laser
The EXCIMER laser, which is a specific type of "cool" laser, generates its power from light in the ultraviolet range. It cannot be visualized by the human eye. Because the laser does not generate any heat, there is no tissue damage as the result of the laser light. The energy of the laser simply causes miniscule amounts of corneal tissue to dissociate a microscopic level.
As the treatment with the laser proceeds, microscopic layers of tissue, approximately 1/10th the width of a human hair are removed. The laser is programmed to remove precisely the amount of tissue needed to achieve the desired visual result.