Early clinical effects of accelerated UVA/riboflavin corneal collagen cross-linking combined with LASIK for myopia

Abstract

Objective To evaluate at six months after myopia surgery the clinical effects of laser in situ keratomileusis (LASIK) combined with accelerated UVA/riboflavin corneal collagen cross-linking (ACXL). Methods This was a prospective and self-controlled study that included 18 myopia patients (36 eyes). LASIK was performed using femtosecond and excimer lasers. Before the flap was reset, single-use Vibe Xtra riboflavin drops were instilled in the corneal stromal bed for 90 seconds. A KXL system (Avedro Inc.) was used to irradiate the cornea with UVA light, delivering 30 mW/cm2 of irradiance for 90 seconds. The total exposure dose was 2.7 J/cm2. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), spherical equivalent (SE), corneal topography, thinnest corneal thickness (TCT), and endothelial cell density (ECD) were evaluated preoperatively and six months postoperatively. Paired t-test were used for statistical analysis. Results Mean UCVA changed from 0.93±0.34 (logMAR) to -0.05±0.08, SE from -8.03±1.86 diopter (D) to -0.29±0.39 D, keratometry from 44.79±2.10 D to 37.96±2.32 D, TCT from 524.6±25.2 μm to 437.7±27.0 μm, corneal peak distance from 5.48±0.31 mm to 4.99±0.44 mm, and corneal deformation amplitude from 1.09±0.12 mm to 1.18±0.18 mm. Aside from the ECD and highest corneal concavity radius, changes in the remaining parameters between preoperative and six-month postoperative values were significant (t=-63.02~26.87, P<0.05). None of the patients developed signs of significant regression, ectasia, or keratitis during the follow-up period. Conclusion LASIK combined with ACXL can effectively correct refractive error in patients with myopia. There were no significant complications during the six-month follow-up. But the long-term effects and indications of LASIK combined with ACXL need to be further observed and studied. Key words: Corneal collagen cross-linking; Myopia; Femtosecond laser; Keratomileusis, laser in situ