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O. Fernandez, R. Velasco, O. Baca, A. Babayan; Vectorial Analysis and Comparative Results Between Conventional and Wavefront-Guided Laser in situ Keratomieleusis for VISX S4. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4204.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the type and grade of induced astigmatism, as well as efficacy of conventional and wavefront-guided (WG) laser in situ keratomileusis (LASIK) in the treatment of low and moderate myopia by using the Visx S4 CustomVue wavefront platform
A comparative, prospective, longitudinal study, including 2 groups: Group 1. 40 eyes treated with conventional LASIK and Group 2. 40 eyes treated with WG. The calculation of the induced and astigmatism was made with a vectorial analysis at the first and third month. Preoperative best spectacle-corrected visual acuity (BSCVA), the three principal higher order (uncorrectable by spectacles) Zernike coefficients, the root-mean-square (RMS) of higher order aberrations with 6.0 mm pupil size, WaveScan refraction, postoperative uncorrected visual acuity (UCVA), and manifest refraction were determined. The clinical outcomes were evaluated on the basis of standard formats and criteria. One month postoperatively data are presented.
Preoperatively, mean spherical equivalent (SE) for WG and conventional group was -3.182 ± 1.511 and -3.895 ± 1.517. Postoperatively, 91.4% of the WG group gained an SE of ± 0.5D, compared with 88% for convencional group. 95.7% of the WG group had an UCVA of 20/20 or better, compared with a 92.3% for conventional (P=0.019). Moreover, the increase in Zernike coefficients in wg LASIK group was statistically smaller than that in conventional LASIK group (P<0.05). The induced and astigmatism was 1.33 x 5.76º for wg and 2.0 x 178º for conventional LASIK.
Wavefront-guided LASIK is efficient to reduce higher order aberrations especially spherical and coma aberrations, and to improve postoperative visual acuity compared with conventional LASIK. The application of vectorial analysis shows a major grade of induced astigmatism with the conventional group but this difference is not statistically significative.
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