Analysis of Microkeratome Thin Flap Architecture Using Fourier-domain Optical Coherence Tomography

PURPOSE: To assess the corneal architecture and reproducibility of LASIK flap thickness created by the Amadeus II mechanical microkeratome (Ziemer Ophthalmic Systems AG) using Fourier-domain optical coherence tomography (OCT; Optovue Inc). METHODS: Anterior segment Fourier-domain OCT was used to analyze the morphology of 58 LASIK flaps from 30 patients created with the Amadeus II microkeratome 140-mu m head and ML7090CLB blades (Med-Logics Inc) at 2 weeks postoperatively. Flap thickness was assessed at 10 points across the central 6 mm of the cornea (horizontal and vertical meridians). Postoperative central corneal flap thickness measured by Fourier-domain OCT was compared with intraoperative ultrasound pachymetry measurements. RESULTS: No significant difference was noted between central flap thickness measured by intraoperative pachymetry (107.2 +/- 14 mu m) and postoperative OCT (111.7 +/- 11 mu m; P = .07, correlation coefficient = 0.86). Fourier-domain OCT measurements demonstrated functionally planar flap architecture (standard deviation [SD] of thickness across the flap = 4.9 mu m, SD range across the flap = 2 to 9 mu m) for the microkeratome flaps. CONCLUSIONS: The Amadeus II microkeratome with Med-Logics blades created thin, reproducible, functionally planar flaps as measured by Fourier-domain OCT. Central flap thickness measured by intraoperative ultrasound pachymetry was equivalent to that measured 2 weeks postoperatively by OCT. [J Refract Surg. 2011;27(10):759-763.] doi:10.3928/1081597X-20110812-03