Abstract
Purpose :
The conventional CXL (C-CXL) procedure removes corneal epithelium and increases corneal densitometry. Accelerated transepithelial corneal collagen cross-linking (ATE-CXL) is a newly developed CXL technique, which maintains the integrity of corneal epithelium layer. We investigated the changes in corneal densitometry after ATE-CXL for progressive keratoconus by using an automatic Scheimpflug Densitometry Program.
Methods :
Forty eyes of 40 participants including 20 eyes of 20 patients (24.9±6.5 years, 13 male and 7 female) diagnosed with progressive KC (KC group) and 20 eyes of 20 myopic patients (24.9±6.5 years, 13 male and 7 female, Control group) were recruited. Corneal topography and corneal densitometry were evaluated before ATE-CXL and at the 1-, 6-, and 12-month follow-up visits. Manifest refraction spherical equivalent (MRSE) and best-corrected distant visual acuity (BCDVA) were assessed before and at 12-month after the procedure.
Results :
MRSE remained stable (t=0.458, P=0.652) but BCDVA improved significantly (Z=-2.857, P=0.004) at 12 months after ATE-CXL. The densitometry values (annulus 0 to 6mm in diameter) of the anterior layer, central layer, posterior layer and the total thickness of the corneas in the KC group were all significantly higher than those in the control group (All P values <0.01). After ATE-CXL procedure, the densitometry values (over the annulus 0 to 2mm area) of the anterior layer (F=4.729, P=0.005), central layer (F=7.960, P<0.001), posterior layer (F=6.622, P=0.001) and total thickness (F=6.551, P=0.001) decreased significantly, as well as over the annulus 2 to 6mm area (F=3.961, P=0.012; F=9.739, P<0.001; F=7.130, P<0.001 and F=6.415, P<0.001,respectively). Although the densitometry values all decreased in the 12 months postoperatively, they were still statistically higher than those of the control group (All P values <0.01).
Conclusions :
The densitometry values of progressive KC patients were higher than those of the myopic ones. The main topographic parameters remain stable, but the densitometry values decreased steadily during the first year after ATE-CXL. At 12 months postoperatively, the densitometry values of progressive KC patients remains higher than those of the myopic population.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.