Clinically significant laser in situ keratomileusis flap striae

Abstract

To describe the incidence, risk factors, and outcomes before and after irrigation of clinically significant laser insitu keratomileusis (LASIK) flap striae. Multisurgeon multicenter standardized protocol practice. Retrospective case-control series. Eyes with striae necessitating flap relift and irrigation were identified. Preoperative, intraoperative, and postoperative variables were collected. Incidence, risk factors, and outcomes were assessed. Of the 109 403 eyes that had LASIK, the incidence of striae-treated eyes was 0.79% (n=875), with 8.7% irrigated the first hour after surgery. The preoperative spherical equivalent (SE)and ablation depth exponentially increased the striae risk (R2=0.9674; P<.001). Striae induced a small hyperopic shift that reversed after the relift (mean 0.22 diopter [D]±0.52 [SD] versus -0.02±0.45 D) (P<.001). After relifting, 68.0%, 87.0%, and 96.0% of eyes had an uncorrected distance visual acuity (UDVA) of 20/20, 20/25, 20/40 or better versus 25.0%, 55.0%, and 84.0%, respectively, before the relift (P<.001). Thirteen percent fewer striae-treated eyes achieved a UDVA of 20/20. Before relifting, 51.0% of striae eyes lost 1 or more lines of corrected distance visual acuity, with a safety index reverting to control values (0.99 versus 1.00) (P>.05) after the relift. A laser refractive enhancement was performed in 6.28% of relifted striae eyes versus 3.04% in nonstriae control eyes. Flap striae requiring surgeon intervention occurred in 0.79% of eyes. Higher preoperative SE values were associated with an exponential increase risk for striae. Treatment by lifting and irrigation significantly improved the accuracy, efficacy, andsafety to a level close to that of contralateral control eyes, although striae-treated eyes were more likely to need excimer laser retreatment.