Abstract
Background
This study analyzed regional corneal thickness remodeling, biomechanical properties, and visual outcomes after femtosecond laser-assisted in situ keratomileusis combined with intraoperative accelerated corneal collagen crosslinking (LASIK Xtra) for myopia.
Methods
This retrospective study comprised 21 consecutive patients (18 women and 3 men; 42 eyes) who were treated with LASIK Xtra. All treatments were performed with ultraviolet-A (energy, 2.7 J/cm2; irradiance, 30 mW/cm2), using continuous (90 s) illumination. Postoperative values of corneal biometrics and visual outcomes were compared with preoperative values. Corneal thickness changes were evaluated using anterior segment optical coherence tomography. All patients were followed up for 12 months postoperatively. Preoperative and postoperative data were compared statistically using the paired t-test for normally distributed parameters and the Wilcoxon rank-sum test and Friedman analysis of variance with Bonferroni correction for non-normally distributed data.
Results
Uncorrected distance visual acuity (UDVA) significantly improved at 6 months after surgery (P < 0.001). The central and inner regional corneal epithelial thickness significantly increased after LASIK Xtra (P < 0.05 for all), while peripheral corneal epithelial thickness remained stable at 12 months after surgery. There was also a statistically significant decreased in the stromal thickness at most locations (P < 0.05 for all), except in the outer superior and outer superior-temporal regions.
Conclusion
LASIK Xtra provided predictable postoperative UDVA, corneal curvature, and corneal biomechanical stability. Since the retrospective study results depended on the cohort members’ past information, it is inferred and confirmed that regular corneal thickness remodeling occurred after treatment.
Nonlinear refractive index of porcine cornea studied by z-scan and self-focusing during femtosecond laser processing
