Purpose: To compare the safety and efficacy of standard 30 min epithelium-off cross-linking
(CXL) versus photorefractive keratectomy (PRK) combined with accelerated epithelium-off
cross-linking (AXL) for the treatment of progressive keratoconus (CXL-Plus).
Methods: This study was a prospective multicentre comparative clinical study. A total of
125 eyes of 75 patients with grade 1 keratoconus and documented progression were divided
into two groups. Group A included 58 eyes treated with standard CXL. Group B included 67
eyes treated with combined PRK and AXL. The recorded data included UDVA, CDVA,
subjective and objective refraction, keratometry and pachymetry using corneal topographies
preoperatively and postoperatively at 3, 6, 12 and 24 months of follow-up.
Results: In group A, at 24 months of UDVA and CDVA were improved from
1.12
0.38 and 0.58
0.42 to 0.66
0.20 and 0.20
0.12 (LogMAR
SD). The
spherical equivalent was reduced from 4.03
1.18 to 1.78
1.04 D. The cylinder
reduction was 0.32
0.19 D. In group B, at 24 months of UDVA and CDVA were
improved from 1.26
0.52 and 0.68
0.36 to 0.58
0.28 and 0.20
0.16
(LogMAR
SD). The spherical equivalent was reduced from 4.23
0.95 to
1.92
0.74 D. The cylinder reduction was
1.76 D.
Conclusion: Surprisingly, standard CXL showed close results to CXL-Plus at the 24th
follow-up month. Standard CXL acted as a stabilizing procedure associated with a late
myopic component reduction. CXL-Plus acted as a refractive and stabilizing procedure with
an early effect on both the myopic and the astigmatic component but no later improvements.
StandardCXLseems to be more powerful thanAXLin its long-term effect. Therefore, in the
future, we want to test the combination of PRK with standard CXL.