Comparison of laser in situ keratomileusis flaps created by 3 femtosecond lasers and a microkeratome.

PURPOSE

To evaluate the thickness and side-cut angle of laser in situ keratomileusis (LASIK) flaps created by 1 of 3 femtosecond lasers or a microkeratome using Fourier-domain optical coherence tomography (OCT).

SETTING

Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.

DESIGN

Comparative case series.

METHODS

Flap creation for bilateral LASIK was performed using an IntraLase (femtosecond group 1), VisuMax (femtosecond group 2), or Femto LDV (femtosecond group 3) femtosecond laser or an M2 microkeratome. Flap thickness was determined at 14 points. The side-cut angle was measured in 4 directions at the margin interface. Measurements were taken 2 months postoperatively using an RTVue Fourier-domain OCT device and integrated software.

RESULTS

Femtosecond group 1 comprised 50 eyes; femtosecond group 2, 40 eyes; femtosecond group 3, 64 eyes; and the microkeratome group, 52 eyes. Eyes in femtosecond groups 1 and 2 had relatively even flap configuration. Flaps in femtosecond group 3 and the microkeratome group had a meniscus shape. Flaps in femtosecond group 1 had the least difference between the mean peripheral and the central flap thickness (P<.001). The greatest flap thickness predictability (measured versus intended thickness) was in femtosecond group 3 (P<.001). Flaps in femtosecond group 1 had a side-cut angle closest to 90 degrees (P<.001).

CONCLUSIONS

Flap morphology differed according to the system used. The 3 femtosecond laser systems appeared to be superior to the microkeratome system generally. The 3 femtosecond laser systems also produced different flap configurations depending on their individual mechanisms.