laser(redirected from energy density of a laser)
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See also: chromophore.
See also: chromophore.
laser/la·ser/ (la´zer) a device that transfers light of various frequencies into an extremely intense, small, and nearly nondivergent beam of monochromatic radiation in the visible region, with all the waves in phase; capable of mobilizing immense heat and power when focused at close range, it is used as a tool in surgery, in diagnosis, and in physiological studies.
laserLight amplification by stimulated emission of radiation, Physics A device that provides a focused beam of light with enough energy to cut or coagulate tissue Surgery A tool that focuses light into an intense, narrow beam to cut or destroy tissue Applications Microsurgery, photodynamic therapy, diagnostics Types of lasers Argon-405 nm wavelength, CO2-630 nm, tunable dye-1600 nm, YAG-neodymium-yttrium-aluminum-garnet-10,600 nm. See Argon laser, Excimer laser, Holmium pulsed laser, Nd:YAG laser, PTP laser, Roller ball technique, Selective photothermolysis, Yellow krypton laser.
laserAcronym for Light Amplification by Stimulated Emission of Radiation. A device that produces light of a single, precisely defined wavelength, in which all the waves are in phase with each other (coherent light). This allows the beam to be intensely concentrated, with little tendency to spread out, and permits focusing into a spot of microscopic size. The properties of the various lasers make them invaluable for a variety of medical and surgical purposes, and a many laser types, including argon lasers, various YAG lasers, carbon dioxide lasers, various pumped dye lasers and high-precision excimer lasers, are being exploited for this purpose. See also LASER THERAPY.
laseracronym for light amplification by stimulated emission of radiation; device concentrates high-frequency electromagnetic energy into a (constant or pulsed) beam of monochromatic light (wavelength 660-950 nm); therapeutic action (burning, cutting or tissue stimulation) is dependent on device specification; tissue effects are inhibited by non-steroidal anti-inflammatory drugs and steroids
chronic wound treatment with laser improved healing rates in chronic wounds (after initial deterioration and increase in exudation); used with caution over epiphyseal lines (in children) or photosensitive tissue; contraindicated with neoplasm and haemorrhage; indications: for laser treatment management of bone repair, verrucae, pain relief, myofascial pain, chronic heel pain, rheumatoid arthritis, osteoarthritis, neuralgia, soft tissues and overuse injury, chronic wounds, burns, scar tissue
manner of use laser probe (protected by a layer of cling film) held at 90° to, and in contact with, skin surface
power of a laser laser energy density (in J/cm2) is directly proportional to product of probe power (in watts) and exposure time (in seconds), and inversely proportional to area irradiated (in square centimetres)
tissue effects of laser dose-dependent increased inflammatory response, immunological effects and capillary formation
argon laser A laser with ionized argon gas as the active medium, which emits a blue-green light beam with a wavelength of 514 nm. It may be used to perform iridectomy, iridoplasty, iridotomy, photocoagulation or trabeculoplasty.
excimer laser A gas laser that emits pulses of light in the ultraviolet region (at 193 nm). All the energy is absorbed by the superficial layers (e.g. the corneal epithelium), which are then exploded away or ablated without any change to the underlying or adjacent tissue or material. See photorefractive keratectomy; LASEK; LASIK.
laser interferometry See clinical maxwellian view system.
laser iridotomy See iridotomy.
krypton laser A laser with krypton gas ionized by electric current as the active medium, which emits a light beam in the yellow-red region of the visible spectrum (521 nm, 568 nm or 647 nm). It may be used to perform photocoagulation or trabeculoplasty.
neodymium-yag laser (Nd-Yag) A solid-state laser whose active medium is a crystal of yttrium, aluminium and garnet doped with neodymium ions. It emits an infrared light beam with a wavelength of 1064 nm. It is typically used with a slit-lamp and in conjunction with a helium-neon laser which produces a red beam of light (633 nm) to allow focusing. It may be used to perform capsulotomy, iridotomy or trabecular surgery. Yag is an acronym for yttrium-aluminium-garnet.
laser refraction See laser refraction.
laser refractive keratoplasty See photorefractive keratectomy.
laser trabeculoplasty See laser trabeculoplasty.
Patient discussion about laser
Q. Should I have eye laser surgery? I am 17 and have been wearing glasses since I was a kid. I was thinking of having an eye laser surgery in order to fix my eyesight. What are the risks?
Q. Is there a laser vision correction operation that will correct both near and farsightedness? My optometrist said that typical laservision would require that I wear glasses for reading since it only corrects farsightedness. I'm leery of the technique of doing only one eye for distance and leaving the other "as is" for reading. I seem to recall a brief news report of some new laser vision technique that corrects both near- and farsightedness. Is that true or were they referring to the "one eye for closeup and one eye for distance" type of correction that I'm skeptical about? Thanks!!
Q. I may have to undergo Laser Acupuncture next week. I am taking medicines for the heart attack I had last year and on my sons wish I am following acupuncture and after observation I may have to undergo Laser Acupuncture next week….I am afraid that this laser can lead to cancer …..And I also worried about the impact and effect of the medicine which I am taking…though my attack is in control will it be good to go for laser.?