Long-term results of superficial laser in situ keratomileusis after ultrathin flap creation

Purpose: To study the long-term efficacy, safety, and stability of laser in situ keratomileusis (LASIK) after unintentional ultrathin flap creation less than 80 μm. Setting: University refractive surgery center. Methods: This retrospective case series comprised 25 patients (33 eyes) who had LASIK after flap creation less than 80 μm with the Moria M2 disposable microkeratome (head 90 μm). Flap thickness was measured with intraoperative ultrasound pachymetry. Manifest refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, predictability, stability, complications, patient satisfaction, and confocal microscopy images were studied. Results: The mean follow-up was 14.58 months ± 3.73 (SD) (range 12 to 25 months). The mean flap thickness was 72.1 ± 5.9 μm (range 58 to 80 μm), and the mean preoperative spherical equivalent (SE) refraction was –5.59 ± 2.01 diopters (D) (range −10.25 to −3.25 D). On the first postoperative day, the UCVA was 20/25 or better. The SE manifest refraction was 1.00 D or less in all patients. The mean SE manifest refraction was −0.75 ± 0.55 D (range −1.00 to +0.75 D) (P<.01). At the last follow-up, changes in visual acuity and manifest refraction were not statistically significant; no late postoperative complications were observed. All patients were satisfied with the final outcome. Qualitative analysis of confocal microscopy images revealed interface particles and activated keratocytes. Conclusions: Despite the small sample and retrospective nature of the study, superficial LASIK seemed to be a safe and predictable technique for myopic refractive corrections. Patients were satisfied with the results and had rapid visual recovery with no intraoperative or early or late postoperative complications. If the safety and efficacy of an ultrathin flap are confirmed by additional studies, superficial LASIK could represent a new approach that combines the advantages of surface and lamellar procedures. [Copyright &y& Elsevier]