Surgical and visual outcomes of flap repositioning for various flap-related pathologies post laser in-situ keratomileusis (LASIK)

Abstract

To evaluate the surgical and visual outcomes of flap repositioning for various post-laser-assisted in-situ keratomileusis (LASIK) flap pathologies. Retrospective review of consecutive cases between April 1, 2017 and February 28, 2022, where surgical flap repositioning was performed following LASIK for various flap-related complications. Of the 6018 eyes, 31 needed flap repositioning (0.51%). Indications were flap displacement and folds in 20 eyes (64%), flap subluxation in five eyes (16%), epithelial ingrowth and interface debris in two each, and one eye each of diffuse lamellar keratitis and incomplete flap. Final best spectacle-corrected visual acuity of ≥ 20/25 was obtained in 25/31 (80%) eyes. The efficacy index pre to post repositioning showed significant improvement (0.86 ± 0.39 vs. 0.63 ± 0.29 preop, P = 0.011). Flap repositioning incidence was significantly higher (7/602 (1.16%)) during the COVID lockdown phases compared to the non-COVID lockdown phase (24/5416 (0.44%, P = 0.019)). The COVID group had lower efficacy (0.72 ± 0.36 vs. 0.90 ± 0.39, P = 0.300) and safety indices (0.85 ± 0.24 vs. 1.06 ± 0.35, P = 0.144) compared to the non-COVID group; however, the results were not statistically significant. The flap displacement rate was statistically higher in nasal hinged (microkeratome) flaps (18/2013, 0.89%) compared to superior hinged (Femto) flaps (13/4005, 0.32%) (0.32%, P = 0.003). Our study shows that flap repositioning has a low incidence in LASIK, with the most common indication being flap displacement/folds. The outcome post flap repositioning was poorer during the lockdown period, perhaps due to the inability to follow up early. Early identification and surgical repositioning are successful in both anatomical and visual restoration.