Word: lasering
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...minutes before--to examine your eyes as well as take your medical history and answer your questions. Be sure to tell the doctor if you or anyone in your family has ever had a corneal disorder, diabetes or an autoimmune disease. Such conditions may increase the chances that laser surgery will severely damage your eyesight. If you have particularly dry eyes or an ocular herpes infection, you aren't a good candidate either. If the first surgeon turns you down, don't go shopping for another...
Enter the excimer laser. Originally developed in the 1970s for the precise etching of computer chips, it is a so-called cool laser, meaning that it can cut through almost any material without generating a lot of heat damage. That's just the kind of exacting low-impact tool surgeons needed to rework the delicate tissues of the eye. So a company called Summit Technology, of Waltham, Mass., dedicated itself to figuring out how to adapt the excimer laser to eye surgery. Today, Summit and another company, Visx, of Santa Clara, Calif., dominate the eye-laser industry...
...surgeons first tried using the excimer laser to correct vision in a procedure called photorefractive keratectomy. They scaled off the cornea's outermost protective layer, or epithelium. Then they vaporized some of the underlying tissue with the laser, forcing the cornea to flatten or steepen, depending on the correction. Although the epithelium always grew back, the cornea retained its new shape. It was a big improvement over radial keratotomy, although the healing of the epithelium remained painful...
LASIK solved this problem. Using a delicate cutting instrument called a microkeratome, surgeons made a sideways slice through the cornea's outermost layers, leaving one side attached, and carefully lifted the flap of tissue out of the way. In nearsighted patients, an invisible beam of laser light then trimmed away layers of tissue from the center of the cornea, producing a flatter curve. In farsighted patients, the beam scooped out a doughnut-shaped ring that resulted in a steeper curve. Then the doctors lifted the flap back into place. After a few minutes of drying, it rebonded with the rest...
Some of these limits may change in the next decade as the technology improves. Summit recently acquired a start-up company that is working on a laser that uses radar initially developed for the Star Wars, or Strategic Defense Initiative, to track the eye during the operation. Currently doctors keep the eye steady by asking you to stare at a blinking red dot. If you suddenly shift your gaze, your surgeon can turn the laser off very quickly, but the doctor can't compensate for the small, involuntary eye movements we make all the time. These saccadic motions aren...