Prospective, Randomized, Contralateral Eye Comparison of the Lenticule Decentration Following SMILE: Coaxially Sighted Corneal Light Reflex Versus Tear Film Mark Centration.

Abstract

Purpose: To examine lenticule decentration and visual quality following small incision lenticule extraction (SMILE) using either the coaxially sighted corneal light reflex (CSCLR) or the tear film mark (TFM) centration method.

Methods: A total of 186 eyes from 93 patients were enrolled in this prospective, randomized, contralateral eye comparison study. Each patient had one eye randomly assigned to the CSCLR group (n = 93) and the contralateral eye to the TFM group (n = 93). Visual outcomes, optical zone decentration, contrast sensitivity, corneal higher order aberrations (HOAs), and the relationships between the magnitude of decentration and induced corneal HOAs were evaluated at 3 months postoperatively.

Results: The magnitudes of total decentration (CSCLR: 0.23 ± 0.13; TFM: 0.22 ± 0.13; P = .996), as well as horizontal and vertical decentration, were comparable between the two methods. However, in the angle kappa greater than 200 µm subgroup, a statistically significant smaller horizontal decentered displacement was observed in the CSCLR group (0.01 ± 0.16) compared to the TFM group (0.07 ± 0.18) (P = .024). The induced HOAs and contrast sensitivity were comparable between the two methods (all P > .05). Additionally, significant correlations were identified between total decentered displacement and induced HOAs, including RMS HOAs, RMS coma, vertical coma, and RMS spherical aberration, in both groups.

Conclusions: Both the CSCLR and TFM methods can yield accurate treatment centration and satisfactory visual quality. However, the CSCLR method may contribute to less horizontal decentration in patients with a large preoperative pupil offset. [J Refract Surg. 2025;41(2):e144-e154.].