Centration and Torsion Control Following Lenticule Creation With Keratorefractive Lenticule Extraction: Effect on Aberration and Astigmatism.

Abstract

Purpose: To evaluate the impact of the post-docking centration and cyclotorsion control functions of the ELITA femtosecond laser system (Johnson & Johnson Vision) on visual, refractive, and optical zone outcomes following Smooth Incision Lenticular Keratomileusis (SILK; Johnson & Johnson Vision).

Methods: This clinical study prospectively enrolled 59 eyes from 30 patients who underwent SILK at the Singapore National Eye Centre between May 2022 and May 2023. Surgeon decision determined whether eyes required post-docking manual centration or cyclotorsion adjustment. Functional optical zone (FOZ), decentration, astigmatism, and higher order aberrations were compared between the movement and no movement groups up to 12 months postoperatively.

Results: Centration and cyclotorsion adjustments were required in 29 of 59 eyes (49.2%). Mean movement was 0.07 mm superior and 0.13 mm nasal, and mean cyclotorsion was 4.3° counterclockwise. Suction time showed a borderline significant association with adjustment (P = .050). At 12 months, postoperative spherical equivalent, astigmatism, higher order aberrations, and FOZ did not differ significantly between groups. Mean FOZ area was 27.67 ± 3.17 mm² (movement) and 28.56 ± 3.54 mm² (no movement) (P = .35). All eyes achieved an uncorrected distance visual acuity of 20/40 or better; 66% and 53% achieved 20/20 or better in the movement and no movement groups, respectively (P = .492). No intraoperative or postoperative complications occurred.

Conclusions: Semi-automated centration and cyclotorsion control in SILK allows for precise alignment with comparative results to non-adjusted cases with respect to refractive, astigmatic, optical zone, or higher order aberration outcomes at 12 months.