Clinical outcomes of image-guided cyclotorsion compensation during KLEx with the VISUMAX 800 in the absence of integrated software

Keratorefractive lenticule extraction (KLEx) is an established procedure for correcting myopia and myopic astigmatism. However, static cyclotorsion during patient positioning can reduce the accuracy of astigmatic correction, especially on platforms without integrated cyclotorsion compensation. This study evaluated the clinical outcomes of image-guided manual cyclotorsion compensation using the Callisto Eye system during KLEx performed with the VISUMAX 800. This retrospective study included 130 eyes of 130 patients who underwent KLEx with the VISUMAX 800 femtosecond laser and manual image-guided cyclotorsion compensation. Eyes were divided according to preoperative astigmatism into Group 1 (≥ 1.50 D, 50 eyes) and Group 2 (< 1.50 D, 80 eyes). Visual acuity, refractive outcomes, and higher-order aberrations were evaluated preoperatively and at 1 and 6 months postoperatively. Astigmatic correction was assessed using Alpins vector analysis. At 6 months, uncorrected and corrected distance visual acuity were better in Group 2, which also had lower residual refractive cylinder. Spherical equivalent outcomes were similar between the groups. No eye lost two or more lines of corrected distance visual acuity. Refractive predictability was high overall, with most eyes achieving spherical equivalent values close to the intended target. Vector analysis showed a correction index closer to 1.0 and a lower difference vector in Group 2, whereas eyes with higher preoperative astigmatism showed a mild tendency toward undercorrection. Postoperative higher-order aberrations were generally similar between the groups. KLEx performed with the VISUMAX 800 using image-guided manual cyclotorsion compensation provided favorable visual, refractive, and astigmatic outcomes. This approach may be a practical option when integrated cyclotorsion compensation software is not available, although eyes with higher preoperative astigmatism may still show mild undercorrection.