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Laser technology

Generality/Definition
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    Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery. There are three primary types of refractive errors: myopia, hyperopia and astigmatism. Persons with myopia, or nearsightedness, have more difficulty seeing distant objects as clearly as near objects. Persons with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects. Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. Combinations of myopia and astigmatism or hyperopia and astigmatism are common.
    Source: Provisu look LASIK (medicinenet.com)

Treatment

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    The lasik is present since 10 years in the refractive surgery and it didn't have any changes in the principles, but great changes in the cutting quality and in the efficiency. The lasik technique has the advantage to be able to correct stronger shortsightedness than the surface PRK (Surface Excimer laser). It has a shorter visual recovery delay . The lasik principle ( Laser Assisted In-situ Keratomileusis ). The lasik intervention allows to cut a cornea level ( 160 ), in order to operate directly in the stroma. The operation 1. A succion ring is placed on the eye. It is useful for two reasons: To maintain the eye in a proper position during the operation, to support and to guide the microkeratome in its cutting advancement. 2. The surgeon is placing the microkeratome on the succion ring. 3. The microkeratome advancement is regular and programmed, a corneal flap with a thickness representing 20 or 25% of the cornea ( 160 ) but it will stand together with the cornea with an hinge. 4. Once the cutting is done, the microkeratome comes back to its starting position and the surgeon is able to remove the microkeratome and the succion ring. 5. The surgeon lifts the cornea cover with a surgical spatule. 6. The laser process can begin. It's strictly similar to the surface PRK . 7. At the end of the laser intervention, the surgeon is replacing the cornea cover without any suture and the natural cicatrization is playing its full role in 2 or 3 minutes. 8. A protection shell is placed on the eye treated, because the link cornea flap \ cornea is still fragile for a moment.
    Source: Provisu look Excimer laser correction- LASIK (myopes.com)
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Illustrations

Source: Provisu look Surface Excimer laser (myopes.com)


The laser has ablated one part of the cornea ( orange part ), which offers a flatter refraction surface.

Scientific articles: All recent articles for "Lasers"

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Last modified: Jan 2014
Creation: Jan 2006