Lasers are used in eye surgery. They can take the laser and weld your retina back together with no mark on your eye. Lasers are also used to correct poor vision by reshaping the cornea. One of the newest medical uses for lasers is to make small holes in the heart so that pathways are created for new blood flow. This helps prevent heart attacks.
Lasers can also cut tissue and cauterize the tissue without damaging other tissue around it.