Femtosecond Laser Flap-in-Flap Technique for Correction of Post-LASIK Myopic Regression.

Purpose: To discuss the technique and outcome of what the authors called the "flap-in-flap" technique and report its safety as a procedure for correction of post-laser in situ keratomileusis (LASIK) myopic regression.

Methods: Seven eyes of 4 patients were included in this study. All patients had previously undergone LASIK for compound myopic astigmatism using the Moria M2 micro-keratome (Moria) 8 to 12 years prior to presentation. All had myopic refractive errors at presentation with a spherical equivalent ranging from -1.25 to -3.30 diopters. A new thinner femtosecond laser flap was created in the old LASIK flap and gently raised, and laser enhancement was performed. All patients were followed up 1 week, 1 month, and 3 months after the procedure. At these visits, the uncorrected distance visual acuity (UDVA), refraction, and corrected distance visual acuity (CDVA) were measured. Pentacam (Oculus Optikgeräte GmbH) and corneal anterior segment optical coherence tomography examinations were obtained on the third visit.

Results: All eyes underwent uneventful enhancement using the flap-in-flap technique. All patients showed an improvement in vision, with 100% of eyes reaching a postoperative UDVA equal to or better than the preoperative CDVA. None of the eyes showed intraoperative complications such as gas breakthroughs or difficult dissections, and no postoperative flap-related complications were seen.

Conclusions: This study describes a technique for post-LASIK enhancement that is surgically safe and shows excellent visual outcomes with the potential to conserve the residual stromal bed and percentage of tissue altered, thus avoiding the risk of post-enhancement ectasia.