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R. Haverly, C. Haverly; Comparison of Microstriae Created with Femtosecond Lasik to Mechanical Microkeratome Lasik. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2877.
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© ARVO (1962-2015); The Authors (2016-present)
A retrospective comparison of 124 consecutive eyes that underwent laser in situ keratomileusis (LASIK) using a femtosecond laser keratome to 124 eyes that underwent LASIK using a mechanical microkeratome.
124 consecutive LASIK cases using the femtosecond laser keratome 110 micron flap (Intralase FS60; Advanced Medical Optics, Inc, Santa Anna, California) and the VISX S4 excimer laser (Advanced Medical Optics, Inc, Santa Anna, California) termed ilasiktm were evaluated before and after LASIK with comprehensive examination including refraction, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), corneal topography, wavefront analysis, slit lamp biomicroscopy, and notation of visible microstriae with slit lamp biomicroscopy. The results were compared with a matched group of 124 cases treated with the Hansatome 180 Micron head (Bausch & Lomb, Rochester, New York) and the same excimer laser. All surgeries were done by the same surgeon.
Of the 124 consecutive LASIK cases using the femtosecond LASIK cases, 2 were noted to have visible microstriae. Of the 124 the mechanical microkeratome cases, 9 were noted to have visible microstriae. The patients in both groups with visible microstriae were asymptomatic and BCVA was 20/20 or better. There was statistical significance between the two groups of P=0.029 using a t-Test. The incidence of microstriae was 1.6% in the femtosecond group and 7.3% in the mechanical microkeratome group. There was no statistical difference in age, sex, central corneal thickness, pre-operative refraction, preoperative keratometry, final BCVA, or UCVA.
The femtosecond and mechanical keratome create different morphologic features in the lasik flap. The femtosecond laser creates a planar shape flap and the mechanical keratome creates a meniscus shaped flap. The flap edges and stromal bed irregularities are different as well. These differences may account for the increased incidence of microstriae with the mechanical keratome group.
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