Abstract:

Objective    To compare the features of corneal flaps created using the FS200 and Moria M2 microkeratome 90μm-knife. Methods    A pilot and prospective study was designed. Ninety eyes of 145 patients were enrolled in this clinical trial. The patients were divided into the FS200 group (50 eyes) and the M2 microkeratome 90μm-knife group (40 eyes), with matching demography. Fourier-domain optical coherence tomography (RTVue OCT) was used to measure flap thickness using 10 settings on the 90 corneas at one week post-operatively. The features of the LASIK flaps were analyzed on the basis of the outcomes. Written informed consent was obtained from each patient prior to LASIK. Results    The mean flap thickness of the FS200 group was considerably thinner than that of the Moria 90 group (112.2±3.2μm versus 128.2±11.2μm) (P<0.01). The corneal flaps in both the FS200 groups showed a flat shape and in the Moria 90 group showed a meniscus shape. The central flap thickness of the FS200 group was not evidently different from that of peripheral(P>0.05), but in the Moria 90 group, the central flap thickness was obviously thinner than the peripheral thickness (P<0.05). The mean deviation between the achieved and attempted flap thickness (110μm) was (2.99±4.34)μm in the FS200 group and (16.82±9.72)μm in the Moria 90 group (P<0.01).  Conclusion    The shape of flaps created using the FS200 is more uniform and closer to the expected thickness of 110μm than the ones created using the Moria M2 90 microkeratome.

Key words: Laser in situ keratomileusis, Fourierdomain optical coherence tomography, Flap thickness, femtosecond laser； Microkeratome