The Evaluation of the Parameters Affecting Flap Thickness in LASIK Surgery

Objective: To evaluate the factors affecting flap thickness (FT) in LASIK surgery using the MK-2000 microkeratome. Materials and Methods: One hundred and fifty-nine eyes of 82 cases with myopia and/or myopic astigmatism who underwent LASIK surgery were included. The MK-2000 microkeratome was used in all cases. The patients were divided into two groups according to microkeratome heads (Group 1: 130 μm, Group 2: 160 μm). The actual FT was calculated by subtracting the pachymetric thickness of the central corneas before and after lifting the flap. The impact of age, preoperative central corneal thickness (CCT), and refractive and keratometric values on FT was determined. In addition, the possible effects of the first and second usage of the same microkeratome were also evaluated in cases with bilateral LASIK surgery. Results: The mean FT was found to be lower in the study group (t=21.35 and t=18.78, P 0.001) than expected. There was a significant positive correlation between FT and preoperative CCT. In bilateral LASIK cases, FT was not significantly different between the first and second eyes in Group 1. However, the FT values of the first eye were found to be thicker than those of the second eye in Group 2. Conclusion: Although the obtained FT values were thinner than the expected theoretical FT, we did not encounter any microkeratome-related flap complications. Therefore, the MK- 2000 microkeratome may be used as a reliable and safe method for LASIK surgery.