Abstract
Purpose: :
To describe the effect of ultraviolet A irradiation (UVA) collagen cross-linking (CXL) performed at the time of LASIK (LASIK Xtra) for high myopia.
Methods: :
48 patients with high myopia who underwent bilateral LASIK were evaluated peri-operatively for UCVA, BSCVA, refraction, keratometry (K), topography (T), total and flap pachymetry (tP and fP), and endothelial cell count (ECC). In each eye at the completion of LASIK, a single instillation of 0.1% riboflavin sodium phosphate was administered in the flap interface prior to flap repositioning. In one eye of each patient (group A eyes), high-fluence CXL was applied (10mW/cm2 for 8 minutes). No CXL was applied in the contralateral eye (group B eyes). The mean follow up was 2.5 years (1 to 3.5).
Results: :
Mean values for Group A and Group B respectively were: UDVA on postoperative day 1: 20/25 and 20/20, UDVA at 6 months: 20/22 and 20/25, BSCVA at 6 months: 20/12 and 20/12, preoperative and postoperative spherical equivalent: -7.5 D to -0.2 D and -7.4 D to -0.4 D, preoperative and postoperative K: 44.5 D to 38 D and 44.6 D to 38.5 D. Regression of greater than 0.5 D requiring re-treatment was seen in 1 eye from group A and 5 eyes from group B.
Conclusions: :
LASIK Xtra appears to be a safe and effective adjunct treatment against potential ectasia during the follow-up period of this study. It appears to delay UDVA by 1-2 days, but may confer higher stability than standard LASIK and may prevent ectasia.
Keywords: refractive surgery: LASIK • keratoconus • myopia