Purchase this article with an account.
Anders Ivarsen, Anders Vestergaard, Sven Asp, Jesper Hjortdal; Corneal Aberrations after Laser in situ Keratomileusis (LASIK) for Moderate to High Myopia: Comparison of Mechanical Microkeratome versus Visumax Femtosecond Laser. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5760.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To compare corneal wavefront aberrations after microkeratome based LASIK and femtosecond LASIK (FS-LASIK) using a Visumax femtosecond laser.
Twenty-three patients received LASIK and 26 patients FS-LASIK in both eyes. LASIK and FS-LASIK treated patients were comparable with respect to all preoperative parameters including age, visual acuity, refractive correction, and corneal aberrations. Preoperative spherical equivalent refraction averaged -8.0 ± 1.3 D with a maximal astigmatism of -3.0 D. In LASIK, flaps were cut using a Moria M2 microkeratome with single use 90 heads. In FS-LASIK, a 500kHz Visumax femtosecond laser was used to cut flaps with a diameter of 8 mm, a thickness of 110 µm, and a cut-angle of 70 degrees. In all eyes, a MEL-80 flying spot excimer laser was used for photoablation in a 6-mm diameter zone. Clinical examination was performed before and 3 months after surgery and included corneal tomography using a Pentacam-HR. Wavefront aberrations were calculated from corneal front surface topography and decomposed into Zernike polynomials up to the 8th order for pupil-sizes of 4 and 6 mm.
After three months, LASIK and FS-LASIK caused a significant increase in 3rd, 4th, and other higher order aberrations for 4 and 6 mm pupils. When comparing LASIK and FS-LASIK, more spherical aberration occurred in LASIK treated patients (p < 0.01). Furthermore, for a 4 mm pupil, coma-like aberration increased more after LASIK than FS-LASIK (p = 0.02). Three months after surgery, no significant difference was observed in BSCVA. One LASIK treated patient lost two Snellen lines in BSCVA.
This is the first study to compare Visumax FS-LASIK with conventional microkeratome based LASIK. Both LASIK and FS-LASIK cause an increase in corneal higher order aberrations, but coma-like and spherical aberrations increase more in eyes treated with a microkeratome. The planar flap and well-defined undercut margin in FS-LASIK may be speculated to facilitate proper repositioning of the flap, decreasing the impact on visually important post-operative higher order aberrations.
This PDF is available to Subscribers Only