Subjective and Objective Visual Quality Outcomes After KLEx vs KLEx Xtra: A 2-Year Prospective Randomized Trial

To compare the 2-year refractive correction outcomes and subjective and objective visual quality between keratorefractive lenticule extraction (KLEx) and KLEx combined with corneal cross-linking (KLEx Xtra).

Patients with myopia were recruited for KLEx or KLEx Xtra surgeries. Only the right eyes were selected. The cross-linking energy was 2.4 J/cm². Visual acuity and optical quality (objective and subjective) were assessed preoperatively and at 1, 6, 12, and 24 months postoperatively.

A total of 150 participants were enrolled, divided into two groups: the KLEx group (75 eyes) and the KLEx Xtra group (75 eyes). At 24 months, the KLEx Xtra group showed significantly superior refractive stability (manifest refraction spherical equivalent -0.02 ± 0.33 diopters [D]) compared to the KLEx group (-0.18 ± 0.34 diopters; P < .05). A transient increase in higher order aberrations (HOAs) in the KLEx Xtra group was observed during early postoperative recovery, which gradually subsided without long-term adverse visual impact. The KLEx Xtra group demonstrated significantly poorer Optical Quality Analysis System II parameters at the early postoperative period compared to the KLEx group (P < .05), but all metrics became comparable between the groups by 12 to 24 months, Early postoperative increases in HOAs in the KLEx Xtra group resolved by 6 months postoperatively. Subjective quality of vision scores showed no significant intergroup differences at 24 months, except for glare.

KLEx Xtra enhances long-term refractive stability without detriment to visual quality, making it a viable option for patients with borderline risk profiles.