Corneal architecture of femtosecond laser and microkeratome flaps imaged by anterior segment optical coherence tomography
Received 8 May 2008; received in revised form 20 August 2008; accepted 6 September 2008.
Purpose
To assess and compare the morphology of laser in situ keratomileusis flaps (LASIK) created by a 60 kHz femtosecond laser and a mechanical microkeratome.
Setting
Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.
Methods
Anterior segment optical coherence tomography (AS-OCT) (Visante) was used to assess 1 week postoperatively the morphology of 20 LASIK flaps created with the IntraLase femtosecond laser or the Zyoptix XP microkeratome. The flap diameter and flap thickness were assessed at 20 measuring points across each flap. First, the repeatability of the AS-OCT flap measurement was evaluated. On this basis, the dimensions of femtosecond laser flaps and microkeratome flaps were tested and their regularity, reproducibility, and accuracy compared.
Results
The method was approved with a repeatability of maximum 8.9 μm. The femtosecond laser flaps were more regular than the microkeratome flaps (P = .02). The reproducibility of flap morphology was not different in the central 1.0 mm radius area (P = .26); however, the femtosecond laser was significantly more precise than the microkeratome in the peripheral area (P = .001). The mean thickness of the femtosecond laser flap was significantly more accurate than the mean thickness of the microkeratome flap (P = .01), with a mean deviation of +16.9 μm and 40.8 μm, respectively.
Conclusions
The flap architecture created with the femtosecond laser was more regular and accurate than the flap architecture created with the microkeratome.
From the Department of Ophthalmology (von Jagow, Kohnen), Johann Wolfgang Goethe-University, Frankfurt am Main, Germany, and the Cullen Eye Institute (Kohnen), Baylor College of Medicine, Houston, Texas, USA
Corresponding author: Thomas Kohnen, MD, Johann Wolfgang Goethe-University, Department of Ophthalmology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
Neither author has a financial or proprietary interest in any material or method mentioned.
Presented in part at the 21. Kongress der Deutschsprachige Gesellschaft für Intraokularlinsen-Implantation, Interventionelle und Refraktive Chirurgie (DGII), Potsdam, Germany, March 2007.
ABSTRACT