(lā′zĕr )

[Acronym forlight amplification by stimulated emission of radiation]
A device that emits intense heat and power on small target by converting various frequencies of light into a unified beam of a single frequency or wavelength. Lasers can influence cellular chemistry (the photochemical effects) and damage tissues by generating heat (such as producing coagulation, the photothermal effects). They can drill into, cavitate, or explode tissues (photomechanical effects) and can ablate tissues after transforming them into plasma. Lasers can also be used diagnostically (as by illuminating cells or tissues, as in fluorescence). They have many applications in laboratories and in surgical procedures. In ophthalmology, they are used to treat cataracts, diabetic retinopathy, macular degeneration, and retinal detachment; in cardiology, to vaporize arterial obstructions; in dermatology, to obliterate blood vessels and to remove warts, skin cancers, nevi, excess tissue, and tattoos; in gynecology, to remove vulval lesions, including genital warts; in gastroenterology, to control bleeding in the gastrointestinal tract; and in oral surgery and dentistry, to remove tumors. Many kinds of lasers are used depending upon the wavelength and power required, including argon, carbon dioxide, copper vapor, dye, excimer, helium-neon, ion, krypton, neodymium:yttrium-aluminum garnet, and ruby lasers.
Laser safety precautions must be observed: Warning signs should be posted indicating that a laser is being used; equipment must be checked before the procedure; conventional endotracheal tubes must be wrapped with aluminum foil tape (flexible metallic endotracheal tubes insulated with silicone may be used); skin preparation solution should not contain combustible agents; and towels draped around the site must be kept wet. The laser equipment must be moved carefully to avoid jarring the mirrors out of alignment. Alcohol-based skin preparations should not be used.