What is PRK?

 

In PRK, or photorefractive keratectomy, we apply the laser directly to the cornea according to carefully calculated measurements, without creating a flap. For nearsightedness we decrease the relative curvature; for farsightedness we increase the relative curvature. At the conclusion of the procedure we place a transparent “bandage” contact lens over the cornea to promote healing. PRK is presently used to treat nearsightedness, nearsightedness plus astigmatism, farsightedness, and farsightedness plus astigmatism.
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What is LASEK?

 

In LASEK, or laser epithelial keratomileusis, we surgically treat the outermost layer of the cornea to create and move aside a sheet of cells a third the thickness of a LASIK flap (see “The LASIK treatment”). We then apply the laser to reshape the cornea. For nearsightedness we decrease the relative curvature; for farsightedness we increase the relative curvature. At the conclusion of the procedure we replace the sheet of cells and cover the cornea with a transparent “bandage” contact lens to promote healing. LASEK is presently used to treat nearsightedness, nearsightedness plus astigmatism, farsightedness, and farsightedness plus astigmatism. LASEK is reserved for patients who have thin corneas, are at risk of occupational damage to the eye, are reluctant to have a LASIK flap, or have corneal disease that precludes the LASIK procedure.
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PRK versus LASEK

Although PRK and LASEK use basically the same technique, there are minor differences between them. In PRK, epithelium is removed and the outermost layer below the epithelium is treated with laser. In LASEK, epithelium is not removed, but an alcoholic solution is used to cause the epithelial cells to weaken; the surgeon will fold the epithelial layer out of the laser treatment field, and fold it back in its original place after cornea has been reshaped by laser. If the epithelial flap is not strong enough to be laid back in its original place, it will be removed, and the LASEK procedure becomes a PRK procedure.
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