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S.V. Patel, J.W. McLaren, L.J. Maguire, W.M. Bourne; A Randomized–Controlled Study of Bladeless and Microkeratome LASIK . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4331.
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© ARVO (1962-2015); The Authors (2016-present)
To compare outcomes between eyes randomized to LASIK performed with a femtosecond laser (bladeless) and LASIK performed with a microkeratome.
Twenty patients received LASIK for myopia or myopic astigmatism. One eye of each patient was randomized by ocular dominance to flap creation with a femtosecond laser (IntraLase FS, IntraLase Corp., Irvine, CA) with intended flap thickness of 120 µm, and the other eye to flap creation with a microkeratome (Hansatome, Bausch & Lomb, Rochester, NY) with intended flap thickness of 180 µm. Patients were examined before surgery and at 1, 3 and 6 months after surgery. During each visit, backscattered light was measured from digitized high magnification video images of a slit–beam, forward light scatter was measured by a stray light meter, high–contrast visual acuity was measured by electronic–ETDRS, contrast sensitivity was measured by the Functional Acuity Contrast Test, and confocal microscopy in vivo was used to examine keratocytes and measure flap thickness. At 3 months, patients were asked if they preferred the vision in either eye.
Corneal backscatter was higher after bladeless LASIK than after LASIK with the microkeratome at 1 month (P= .003, n=20), 3 months (P= .014, n=20), and 6 months (P= .045, n=13). In both treatments, corneal backscatter was higher at 1 month (bladeless, P= .001, n=20; microkeratome, P= .009, n=20) and 3 months (bladeless, P= .002, n=20; microkeratome, P= .031, n=20) after LASIK than before LASIK. Forward light scatter did not differ between treatments at any time, but was higher at 3 months (bladeless, P= .030, n=20; microkeratome, P= .034, n=20) and 6 months (bladeless, P= .007, n=13; microkeratome, P= .022, n=13) after LASIK than before LASIK. High–contrast visual acuity (corrected and uncorrected) and contrast sensitivity did not differ between treatments at any time. In both treatments, confocal microscopy images showed particles at the interface and activated keratocytes deep to the interface. Flap thickness at 1 month was 142 ± 16 µm (bladeless, mean ± SD, n=20) and 139 ± 22 µm (microkeratome, n=20, P= .563). At 3 months, 7 patients preferred the microkeratome eye, 5 patients preferred the bladeless eye, and 8 patients had no preference. Ocular preference did not correspond to ocular dominance or better uncorrected visual acuity.
High–contrast visual acuity and contrast sensitivity does not differ between eyes receiving myopic bladeless LASIK or LASIK performed with a microkeratome. Although corneal backscatter is greater with bladeless LASIK during the first 6 months after surgery, patients do not perceive a difference in vision.
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