The laser gives energy to the skin, which is absorbed by blood vessels, scars, port wine stains, hemangiomas, and other vascular lesions. This relatively quick, comfortable procedure can eliminate blood vessels by precise tissue heating, i.e. energy is directed against the vessels alone and does not alter the surrounding skin. Usually, the vessels collapse during the treatment session, but there can be some post-treatment redness and swelling. Following treatment sessions with aggressive sun protection practices can produce longer-lasting results and prevent formation of similar lesions.