Excimer laser-based refractive surgery is a brilliant idea aimed at replacing the need for glasses or contact lenses. It has been improved significantly during the last decade for precision correction of refractive errors with less pain and fewer adverse effects. The refractive results of this method are excellent. The potential problem lies elsewhere.
This procedure involves a laser beam at 193 nm that practically evaporates part of the cornea, breaking cells and molecules to create the smooth surface necessary for the best optical results. The creation of free radicals, therefore, is an inseparable part of the corneal-reshaping process.1-4 Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) are known to cause keratocyte apoptosis within the corneas of laboratory animals.1,3 Although it is not possible to foresee the long-term effects of corneal keratocyte apoptosis, it is reasonable to assume that these cells fulfill a function within the corneal structure and that even if no short-term damage is apparent, long-term damage must be considered. These procedures are also known to cause biochemical and ultrastructural modifications in the lens, both of which are markers of cataractogenesis.5-7 Because the vitreous base is located immediately behind the lens, there is every reason to expect that it will be affected by the same process that affects the cornea, the anterior chamber, and the lens.
Ben-nun J. Photorefractive Keratectomy and Laser In Situ Keratomileusis: A Word From the Devil's Advocate. Arch Ophthalmol. 2000;118(12):1706–1707. doi:
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