Excimer laser

A laser that emits very concentrated light in the ultraviolet (UV) region of the spectrum. Excimer lasers are used in medicine. For examples, In ophthalmology — to vaporize part of the surface layer of the cornea and thus reshape the cornea to correct refractive errors from myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. In dermatology — to treat psoriasis and vitiligo. Technical Note: An excimer laser uses a noble-gas halide. "Excimer" is a chemical term that refers to a substance formed by the joining of two atoms or two molecules of the same chemical composition in an excited state; it is an excited dimer.

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excimer laser n a laser that uses a compound of a halogen and a noble gas to generate radiation usu. in the ultraviolet region of the spectrum

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a laser that can remove very thin sheets of tissue from the surface of the cornea of the eye. This can be done to alter the curvature of the corneal surface, for example to treat long- or short-sightedness (see LASEK, LASIK), or to remove diseased (e.g. calcified) tissue from the corneal surface. See keratectomy.

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[excited dimer] a laser with rare gas halides as the active medium whose beam is in the ultraviolet spectrum and penetrates tissues only a small distance; the beam breaks chemical bonds instead of generating heat to destroy tissue. Used in ophthalmologic and dermatologic procedures and in laser angioplasty.