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Comparison of LASEK and LASIK with thin and ultrathin flaps after excimer laser ablation with the SCHWIND Aspheric ablation profile.

PURPOSE
to compare visual, refractive, and wavefront aberration outcomes of laser epithelial keratomileusis (LASEK), thin-flap LASIK (flap thickness 110 to 130 microm), and ultrathin-flap LASIK (flap thickness <110 microm) after excimer laser ablation with an aspheric ablation profile.


METHODS
a retrospective analysis of 97 eyes of 56 patients with myopia <6.00 diopters (D) sphere (30 eyes, alcohol-assisted LASEK; 30 eyes, LASIK 110; and 37 eyes, LASIK 130) was conducted. Surgery was performed using the SCHWIND ESIRIS Aberration-Free aspheric ablation profile and the Carriazo-Pendular microkeratome.


RESULTS
groups were comparable preoperatively except for lower astigmatism and ocular trefoil (3,+3) in the LASIK 130 group and lower corneal thickness in the LASEK group. At 6 months postoperative, the groups were comparable for uncorrected and corrected distance visual acuity, efficacy index, safety, and refractive predictability. All groups demonstrated improved contrast sensitivity. All groups demonstrated a significant change in spherical aberration compared to preoperative levels. The induced spherical aberration was 0.057 microm/D in the LASEK group, 0.039 microm/D in the LASIK 110 group, and 0.044 microm/D in the LASIK 130 group. Other higher order aberrations did not show significant change except for a reduction in corneal trefoil (P=.034) in the LASEK group and increased ocular trefoil (P=.002) in the LASIK 110 group. The extent of change in higher order aberrations was not significantly different among groups.


CONCLUSIONS
the aspheric ablation profile is safe, effective, and predictable and produces similar visual and refractive results with three different surgical approaches of LASEK, thin-flap LASIK, and ultrathin-flap LASIK. The ablation profile demonstrated a low induction rate of higher order aberrations regardless of surgical approach.