Microkeratome blades and corneal flap thickness in LASIK.

Background And Objective: To determine the corneal flap thickness produced by using two different types of blades on the same microkeratome for LASIK, comparing flap thickness in the first and second eyes.

Patients And Methods: The corneal flap thickness was measured in two sets of 100 consecutive patients undergoing bilateral LASIK procedures using the Moria M2 microkeratome with a 110 head (Moria, France) and either Moria or CLB blades (Med-Logics Inc., Laguna Hills, CA). Corneal flap thickness was determined by intraoperative pachymetry using an ultrasonic pachymeter.

Results: The mean corneal flap thickness was 138.95 +/- 21.6 microm (range: 75-205 microm) with Moria blades and 115.07 +/- 16.0 microm (range: 70-153 microm) with CLB blades, which is a significant difference (P < .001). The difference in flap thickness between the first and second eyes was not significant with the Moria blades (141.46 +/- 21.46 microm vs 136.45 +/- 21.55 microm, P = .965), but it was when the CLB blades were used (123.21 +/- 12.07 microm vs 106.93 +/- 15.51 microm; P= .013).

Conclusion: In LASIK surgery using a Moria M2 microkeratome, blades from different manufacturers may produce significantly different corneal flap thicknesses, as well as differences between the first and second eyes.