This argon fluoride excimer laser was developed by IBM in the early 1980's to etch silicone chips. It was subsequently discovered that the laser could be used to cleanly and precisely remove living tissue.
The VISX Star Laser The laser's high-energy ultraviolet light pulses break molecular bonds but do not heat or damage the surrounding tissue. A thin (.25 micron) layer of tissue is removed with each pulse. The distribution of laser pulses on the cornea is controlled by a computerized shutter. Multiple laser pulses can be used to sculpt the central cornea, changing the cornea's curvature and power.
Thus, the excimer laser is able to reproduce the shape of a contact lens on the front surface of the cornea in less than a minute. For every diopter (the unit of measure which defines refractive power) of correction, approximately 10 microns of corneal tissue are removed. Therefore, correcting 5 diopters of myopia requires the removal of roughly 50 microns of tissue, less than 10% of the corneal thickness.
A hair sculpted by the excimer laser.Clinical treatment of sighted eyes was initiated in 1988. Clinical excimer lasers are very complicated and sensitive instruments requiring careful calibration, monitoring of energy out, and regular maintenance, as is demanded by their meticulous application to surgery of the human cornea.
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