Effect Of Optical Zone–Visual Axis Alignment On Quality Of Vision After Keratolenticule Extraction: Clinical Impact Of The Centrax Centration System

To evaluate the clinical effect of CenTraX (SCHWIND eye-tech-solutions, Germany), a newly developed automated intraoperative centration system designed to compensate for misalignment between the optical zone center and the visual axis during keratolenticule extraction (KLEx) for the correction of myopia and myopic astigmatism.

This study was conducted at Cheong-Ju First Eye Clinic and included patients who underwent keratorefractive lenticule extraction (KLEx) in 2025. A total of 198 eyes were analyzed over a 3-month follow-up period. Of these, 100 eyes treated with the conventional KLEx technique served as the control group, and 98 eyes treated using the CenTraX system comprised the study group.

This retrospective chart review evaluated preoperative, intraoperative, and postoperative clinical data. Preoperative measurements included spherical equivalent (SE) and corneal curvature. Intraoperative video analysis was performed to quantify the offset between the visual axis and the optical zone center, as well as the pupillary offset, defined as the difference between the visual axis and the pupil center. Postoperative uncorrected distance visual acuity (UDVA), spherical equivalent, and higher-order aberrations were assessed at 1 day, 1 week, 1 month, and 3 months after surgery.

There were no significant differences between the two groups in preoperative spherical equivalent, corneal thickness, or pupillary offset. Intraoperative misalignment between the visual axis and the optical zone center did not differ significantly between groups. Postoperative UDVA and spherical equivalent at all follow-up time points (1 day, 1 week, 1 month, and 3 months) were comparable between the groups. However, the change in coma aberration at 1 week, 1 month, and 3 months postoperatively, compared with preoperative values, was significantly lower in the CenTraX group than in the control group.

The application of the CenTraX automated centration system in keratolenticule extraction significantly reduces the induction of postoperative coma aberrations, suggesting a potential improvement in optical quality and quality of vision after KLEx surgery.