Anterior Segment Optical Coherence Tomography Measurement of Flap Thickness After Myopic LASIK Using the Mona One Use-Plus Microkeratome

PURPOSE: To analyze the accuracy and consistency of corneal flap thickness created in myopic LASIK using the Mona One Use-Plus microkeratome compared with the Mona M2 Single Use 90-mu m microkeratome. METHODS: Bilateral LASIK was performed in 68 myopic patients. Flaps were created using the One Use-Plus microkeratome in 82 eyes (41 patients) and the M2 90-mu m microkeratome in 54 eyes (27 patients). Flap complications and visual outcomes were evaluated. Horizontal "High Res. Corneal" scan pattern of anterior segment optical coherence tomography (AS-OCT) was applied to measure flap thickness at five locations (0, +/- 2, and +/- 3.5 mm from the corneal vertex) on the first postoperative day. RESULTS: No significant differences were noted in flap complications and visual outcomes between groups. The central flap thickness was dramatically thinner in the One Use-Plus group (114.7 +/- 10.1 mu m and 109.4 +/- 11.0 mu m for right and left eyes, respectively) than in the M2 group (155.6 +/- 14.8 mu m and 151.6 +/- 12.5 mu m for right and left eyes, respectively) (P<.001) The One Use-Plus did not show a markedly better uniformity than the M2; the variation was mainly observed in the periphery. Multiple linear regression showed that for the One Use-Plus, the steeper the preoperative keratometry, the thicker the flap thickness, and for the M2, the thicker the preoperative pachymetry, the thicker the flap (P<.1). CONCLUSIONS: The One Use-Plus and M2 microkeratomes have similar safety and efficacy. The flap created by the One Use-Plus was much thinner than the flap created with the M2; however, the One Use-Plus can not realize a fully planar-shaped flap. [J Refract Surg. 2010;26(6):403-410.] doi:10.3928/1081597X-20090710-04