Impact of Iris Color and Laterality on Lenticule Extraction Time in Keratorefractive Lenticule Extraction (KLEx)

Purpose: This study aims to evaluate the effects of iris color and laterality on keratorefractive lenticule extraction (KLEx) surgery time. Setting: A retrospective analysis was conducted on 656 eyes of 328 patients undergoing small incision lenticule extraction (SMILE). Mean patient age was 32 ± 7 years. Methods: Preoperative parameters, including manifest refraction spherical equivalent (MRSE), refractive cylinder, and corrected distance visual acuity (CDVA), were measured. Iris color was classified as “light” (n = 390) or “dark” (n = 266) by a senior ophthalmologist as the grader. Surgical time was determined from video recordings, defined as the time between opening of the KLEx incision and extraction of the lenticule. The surgery was performed by a single highly experienced, right-handed refractive surgeon. Results: Eyes with light irides showed significantly shorter lenticule extraction times than those with dark irides (75 ± 22 s vs. 90 ± 31 s, p < 0.0001). No statistically significant differences were found between eyes with light and dark irides in terms of postoperative MRSE, refractive cylinder, uncorrected distance visual acuity (UDVA), CDVA, safety and efficacy index, respectively (p > 0.05 for all). Surgical time was significantly shorter in right eyes compared to left eyes (74 ± 25 s vs. 89 ± 27 s, p < 0.0001). When analyzing laterality and iris color, surgery was shortest in right eyes with light irides (68 ± 19 s) and longest in left eyes with dark irides (97 ± 31 s; p < 0.0001). Conclusions: SMILE surgery took significantly less time in patients with light irides and in the right eyes compared to dark irides and the left eyes. These findings suggest that patients’ iris color and laterality in relation to surgeon handedness may influence the ease of surgical lenticule extraction to a comparable extent.