Wavefront-guided LASIK improves contrast sensitivity
SAN FRANCISCO – Wavefront-guided LASIK corrects higher-order optical distortions and provides significantly improved contrast sensitivity compared with standard LASIK. This is the conclusion of a study appearing in the March 2004 issue of Ophthalmology, the clinical journal of the American Academy of Ophthalmology, the Eye M.D. Association. Contrast sensitivity is the visual system's ability to detect subtle shades of gray between an object and its background.
In this comparative study conducted in Israel, 24 eyes of 13 patients were treated with wavefront-guided LASIK and 22 eyes of 12 patients were treated with standard LASIK. At one month after surgery, it was found that 88 percent of the contrast sensitivity measurements improved in the wavefront group, whereas only 40 percent improved in the standard group. Also, uncorrected visual acuity of 20/20 or better was achieved by 72 percent of the wavefront group and by 70 percent of the standard group.
Igor Kaiserman, MD, an ophthalmologist at Hadassah Medical Center in Jerusalem and lead author of the study, explained, "LASIK has a high rate of improving uncorrected visual acuity, but it can degrade the quality of vision, resulting in reports of reduced night vision clarity, glare and halos. This is the result of reduced contrast sensitivity, which is greater among patients with high degrees of nearsightedness. One reason for reduced contrast sensitivity is the increased higher-order distortions caused by the LASIK procedure. Because wavefront measurement provides a more precise and detailed map of the visual system's distortions, wavefront-guided LASIK reduces these distortions, resulting in an improved quality of vision."
Academy spokesperson Scott MacRae, MD, professor of ophthalmology and visual science at the University of Rochester Medical Center, Rochester, New York, said, "I agree that customized wavefront treatments should be incorporated into refractive surgery practices because they minimize higher-order aberrations that are created by conventional LASIK. Customized treatments make LASIK safer, and allow some patients to have sharper vision with greater contrast sensitivity. However, because this study was done on a small number of different patients, the results do not provide conclusive evidence that the wavefront treatment is better for every patient. A paired, bilateral study in which each patient has a wavefront correction and a conventional treatment would be more compelling."
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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