Moving from a Mechanical Microkeratome to a Femtosecond Laser for LASIK to Correct Astigmatic Patients: Clinical Outcomes of a Retrospective, Consecutive, Comparative Study

Abstract

Background: To evaluate outcomes after optimized laser in situ keratomileusis (LASIK) for astigmatism correction with flap created by a mechanical microkeratome or a femtosecond laser. Patients and Methods: In this retrospective study, a total of 102 eyes of 71 consecutive patients were enrolled undergoing optimized LASIK treatments using the Allegretto laser system (WaveLight Laser Technologie AG, Erlangen, Germany). A mechanical microkeratome for flap creation was used (One Use, Moria®) in 46 eyes (31 patients, spherical equivalent [SE] −4.44 D ± 2.4) and a femtosecond laser was used (LDV, Ziemer®) in 56 eyes (40 patients, spherical equivalent [SE] −3.07 D ± 3.3). The two groups were matched for inclusion criteria and were operated under similar conditions by the same surgeon. Results: Overall, the preoperative spherical equivalent was −9.5 diopters (D) to +3.37 D; the preoperative manifest astigmatism was between −1.5 D and −3.5 D. At 6 months postoperatively, the mean postoperative uncorrected distance visual acuity (UDVA) was 0.93 ± 0.17 (range 0.4 to 1.2) in the Moria group and 1.0 ± 0.21 (range 0.6 to 1.6) in the Femto group, which was statistically significant (p = 0.003). Comparing the cylinder power there was a statistical difference between the two groups (p = 0.0015). Conclusions: This study shows that the method of flap creation has a significant impact on postoperative astigmatism with a significantly better postoperative UDVA in the Femto group. These findings suggest that the femtosecond laser provides a better platform for LASIK treatment of astigmatism than the commonly used microkeratome.

Zusammenfassung

Hintergrund: Ziel war die Auswertung von LASIK-Ergebnissen, wobei die Flaps mit einem Femtosekunden-Laser (LDV, Ziemer) oder einem mechanischen Mikrokeratom (One Use, Moria) erzeugt wurden. Patienten und Methoden: Retrospektive Studie mit 102 Augen von 71 konsekutiven Patienten nach optimierter LASIK mit dem Allegretto Laser System (WaveLight Laser Technologie AG, Erlangen, Germany). Ein mechanisches Mikrokeratom zur Flaperzeugung wurde (One Use, Moria®) bei 46 Augen benutzt (31 Patienten, sphärisches Equivalent [SE] −4,44 D ± 2,4), ein Femtosekunden-Laser (LDV, Ziemer®) bei 56 Augen (40 Patienten, SE −3,07 D ± 3,3). Die beiden Gruppen wurden abgeglichen und unter ähnlichen Bedingungen operiert. Ergebnisse: Insgesamt betrug das präoperative SE −9,5 Dioptrien (D) bis +3,37 D; der präoperative Astigmatismus war zwischen −1,5 D und −3,5 D. Nach 6 Monaten betrug die durchschnittliche unkorrigierte Sehschärfe 0,93 ± 0,17 (von 0,4 bis 1,2) in der Moria-Gruppe und 1,0 ± 0,21 (von 0,6 bis 1,6) in der Femto-Gruppe. Dieser Unterschied war statistisch signifikant (p = 0,003). Bei der Zylinderstärke fand sich ebenfalls ein statistisch signifikanter Unterschied zugunsten der Femto-Gruppe (p = 0,0015). Schlussfolgerungen: Die Studie zeigt auf, dass die Methode der Flap-Erzeugung einen signifikanten Einfluss auf den postoperativen Astigmatismus hat und mit einer besseren postoperativen Sehschärfe in der Femto-Gruppe assoziiert ist. Diese Resultate suggerieren, dass der Femtosekunden-Laser eine bessere Plattform für die LASIK-Behandlung von Astigmatismus bietet als das Mikrokeratom.

Key words

LASIK - Femto-LASIK - microkeratome - femtosecond laser

Schlüsselwörter

LASIK - Femto-LASIK - Mikrokeratom - Femtosekunden-Laser

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