To purpose of this study was to evaluate complications of unintended thin corneal flap in laser in situ keratomileusis (LASIK), such as visual acuity and myopic regression, at the one year follow-up. We performed a study on 54 eyes, i.e. 27 patients, having LASIK. The eyes were split into two groups, group one, 27 eyes with unintended thin corneal flap with a thickness of 100 µm or less, and as a control group, 27 eyes with a thickness of 110 µm or more. The average corneal flap thicknesses of the two groups were 88.89 ± 8.07 µm and 132.70 ± 19.58 µm, respectively. With regard to postoperative complications, there were no statistical differences between the groups for: foreign bodies in aspects of the interface, mild peripheral infiltration, superficial punctuate keratitis, myopic regression and decreased vision. The only complication showing any statistical difference between the two groups was the central corneal opacity. An unintended thin corneal flap, with an intact Bowman's layer, induced no significant postoperative complications. Central corneal opacity was apparent in 4 of the eyes in group one, so may be related with a thin corneal flap.