Clinically significant laser in situ keratomileusis flap striae.

PURPOSE: To describe the incidence, risk factors, and outcomes before and after irrigation of clinically significant laser in situ keratomileusis (LASIK) flap striae.

SETTING: Multisurgeon multicenter standardized protocol practice.

DESIGN: Retrospective case-control series.

METHODS: Eyes with striae necessitating flap relift and irrigation were identified. Preoperative, intraoperative, and postoperative variables were collected. Incidence, risk factors, and outcomes were assessed.

RESULTS: 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.

CONCLUSIONS: 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, and safety to a level close to that of contralateral control eyes, although striae-treated eyes were more likely to need excimer laser retreatment.