Background/aim To compare stromal bed smoothness in LASIK flaps created with two different femtosecond lasers (IntraLase FS150 and WaveLight FS200) and a mechanical microkeratome (MMK) (Carriazo-Pendular microkeratome).

Methods Sixty freshly enucleated porcine eyes were used for the study. Twenty flaps were created and constitute each of the following three groups: IntraLase FS150 (IFS group), WaveLight FS200 (WFS group) and MMK (MMK group). In each of the three groups, 10 flaps were created with intended thickness of 110 μm and another 10 flaps with 130 μm. Images were assessed with light microscopy and scanning electron microscopy. Qualitative surface roughness grading of the images was performed by five masked observers and statistical comparisons of scores were made between groups.

Results The results of qualitative surface roughness grading demonstrated that there was no significant difference between the two femtosecond (FS) lasers when comparing the subgroups with the same flap thickness (p>0.05 in both comparisons, Mann–Whitney U test). In addition, there was no statistically significant difference (p>0.05) in each flap maker group between different thickness subgroups. However, the scores of the FS laser subgroups were significantly better than the scores of the MMK subgroups with corresponding flap thicknesses (p<0.05, Mann–Whitney U test).

Conclusions Our study demonstrates that the IntraLase FS150 and the WaveLight FS200 had a similar performance and provided flaps with smooth surfaces. In comparison to the MMK, the studied femtosecond laser systems had a superior performance in terms of smoothness.