To report a case of irregular astigmatism caused by a free flap during laser-assisted in situ keratomileusis (LASIK) surgery that was treated with a flap rotation based on postoperative topography.

A 21-year-old female underwent LASIK, which was complicated by a free cap on her right eye. Because the gentian violet markings were no longer present, the exact orientation of the cap was unknown. At 3 months after surgery, the astigmatism of the right eye was −3.00 diopters (D) with an uncorrected visual acuity (UCVA) of 0.4, and the astigmatism of the left eye was −0.75 D with an UCVA of 1.0. The corneal topography was analyzed in order to return to the existing position. Free cap repositioning was performed and irregular astigmatism was corrected to improve the UCVA to 1.0.

If the preoperative markings cannot be identified on a free flap during LASIK, secondary postoperative corneal topographic analysis can be performed to restore the corneal free flap to its original position to minimize astigmatism with good visual outcomes.