update on surgical procedures
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An Update on Refractive Surgical Procedures
Expanding Options for Visual Improvement Ophthalmologists have used laser surgery to improve the vision of millions of patients since the technology entered mainstream use in the late 1980s. Refractive surgery tools and techniques are increasingly sophisticated, and specialists can now overcome anatomical issues that previously excluded patients from surgery and correct a broader range of refractive errors. Laser refractive surgeries currently can correct errors between -14 and +5 diopters with up to 6 diopters of astigmatism, says UAB ophthalmologist Andrew J. Velazquez, MD, who notes advances in laser technology are constantly expanding this range on both ends of the visual spectrum. Laser in situ keratomileusis (LASIK) is the most commonly performed refractive surgery, he says. “Of current refractive procedures, LASIK offers the least discomfort and the most rapid postoperative healing and visual improvements. Epi-LASIK, photo refractive keratectomy [PRK], and laser epithelial keratomileusis [LASEK] are usually reserved for patients whose corneas are too thin or shaped in a way that rules out LASIK.” Velazquez and other UAB ophthalmologists also perform wavefront-guided, or custom, LASIK. This novel technology measures tiny distortions in visual light processing and creates a detailed map of the patient’s refractive error. “Wavefront-guided LASIK can correct higher-order aberrations and improve visual performance in a way glasses and traditional refractive laser procedures cannot,” he says. When a wavefront of light passes through a perfect eye (and such eyes exist only in theory), it creates a perfectly flat, distortion-free plane. When a wavefront penetrates eyes with refractive errors, a variety of irregular three-dimensional shapes, or aberrations, are created. Lower-order aberrations — myopia, hyperopia, and astigmatism — makeup about 85% of all visual errors. Higher-order aberrations produce less-common visual irregularities such as decreased contrast sensitivity, blurriness, glare, halos, shadows, and poor night vision. Wavefront-guided LASIK uses a computerguided excimer laser to remove tiny, precise portions of tissue and reshape the cornea, Velazquez says. “Conventional LASIK, glasses, and contact lenses can significantly improve visual acuity as measured by a standard 20/20 eye chart, but custom LASIK also can enhance visual quality, increasing sharpness and contrast sensitivity, as well as reducing glare and halos.” Monovision Although refractive surgeries can rectify a broader range of refractive errors than ever before, they cannot correct presbyopia. Monovision is an option for patients with aging eyes who are having difficulty with near-vision tasks and who want to avoid reading glasses. “Using LASIK or PRK, we can reshape one eye for near vision and the other for distance vision. Monovision causes a loss of depth perception, and some patients cannot adapt to the change. Patients considering this procedure may wish to test drive contact lenses that produce monovision before undergoing surgery,” says Velazquez, who notes he oversees patients throughout the surgical process, performing the procedures and providing pre- and postoperative care. FATIMA MAE A. ALPAPARA BSN-4B(Group 1)
Expanding Options for Visual Improvement Ophthalmologists have used laser surgery to improve the vision of millions of patients since the technology entered mainstream use in the late 1980s. Refractive surgery tools and techniques are increasingly sophisticated, and specialists can now overcome anatomical issues that previously excluded patients from surgery and correct a broader range of refractive errors. Laser refractive surgeries currently can correct errors between -14 and +5 diopters with up to 6 diopters of astigmatism, says UAB ophthalmologist Andrew J. Velazquez, MD, who notes advances in laser technology are constantly expanding this range on both ends of the visual spectrum. Laser in situ keratomileusis (LASIK) is the most commonly performed refractive surgery, he says. “Of current refractive procedures, LASIK offers the least discomfort and the most rapid postoperative healing and visual improvements. Epi-LASIK, photo refractive keratectomy [PRK], and laser epithelial keratomileusis [LASEK] are usually reserved for patients whose corneas are too thin or shaped in a way that rules out LASIK.” Velazquez and other UAB ophthalmologists also perform wavefront-guided, or custom, LASIK. This novel technology measures tiny distortions in visual light processing and creates a detailed map of the patient’s refractive error. “Wavefront-guided LASIK can correct higher-order aberrations and improve visual performance in a way glasses and traditional refractive laser procedures cannot,” he says. When a wavefront of light passes through a perfect eye (and such eyes exist only in theory), it creates a perfectly flat, distortion-free plane. When a wavefront penetrates eyes with refractive errors, a variety of irregular three-dimensional shapes, or aberrations, are created. Lower-order aberrations — myopia, hyperopia, and astigmatism — makeup about 85% of all visual errors. Higher-order aberrations produce less-common visual irregularities such as decreased contrast sensitivity, blurriness, glare, halos, shadows, and poor night vision. Wavefront-guided LASIK uses a computerguided excimer laser to remove tiny, precise portions of tissue and reshape the cornea, Velazquez says. “Conventional LASIK, glasses, and contact lenses can significantly improve visual acuity as measured by a standard 20/20 eye chart, but custom LASIK also can enhance visual quality, increasing sharpness and contrast sensitivity, as well as reducing glare and halos.” Monovision Although refractive surgeries can rectify a broader range of refractive errors than ever before, they cannot correct presbyopia. Monovision is an option for patients with aging eyes who are having difficulty with near-vision tasks and who want to avoid reading glasses. “Using LASIK or PRK, we can reshape one eye for near vision and the other for distance vision. Monovision causes a loss of depth perception, and some patients cannot adapt to the change. Patients considering this procedure may wish to test drive contact lenses that produce monovision before undergoing surgery,” says Velazquez, who notes he oversees patients throughout the surgical process, performing the procedures and providing pre- and postoperative care. FATIMA MAE A. ALPAPARA BSN-4B(Group 1)
