| dc.description.abstract | Purpose: To compare the outcomes of corneal collagen cross-linking (CXL) for the treatment of progressive keratoconus using 2 different techniques for epithelial removal: transepithelial phototherapeutic keratectomy (t-PTK) + CXL versus mechanical epithelial debridement.
Design: retrospective comparison study.
Participants: Two hundred and twenty patients (298 eyes) with progressive keratoconus were included.
Method: All patients underwent uncomplicated CXL treatment. Hundred and ten patients (155 eyes) underwent epithelial removal using t-PTK (group 1) and ninety-five patients (143 eyes) underwent mechanical epithelial debridement using a Amoils rotating brush (group 2) during CXL treatment. Visual and refractive outcomes were evaluated with keratometric and aberrometric values preoperatively at 12±6 months postoperatively.
Main outcome measures: Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive spherical equivalent (MRSE), and keratometry readings as steepest radius of anterior curvature (Kmax), and corneal astigmatism (AST.). Additionally, aberometric values root mean square (RMS) and higher order aberrations (HOAs). Secondary outcomes; subjective spherical power, subjective astigmatic power, steepest meridian (K2), flattest meridian (K1) and spherical aberrations (Z40).
Results: In group 1, Snellen decimal mean UDVA and mean CDVA improved from 0.41 ±0.24 and 0.96 ±0.20 preoperatively to 0.67 ±0.32 (p <.001) and 1.03 ±0.19 (p < .005) at 12±6 months postoperatively, respectively. In group 1, mean UDVA improved from 0.50 ±0.35 preoperatively to 0.54 ±0.38 (p <.005) at follow-up, whereas group 2 mean CDVA demonstrated no significant improvement at 12±6 months postoperatively (p >.05). In group 1, Kmax improved from 53.15 ±4.3 dioptres (D) preoperatively to 50.99 ±4.68 D (p <.001), and in group 2 Kmax improved from 53.92 ±8.26 dioptres (D) preoperatively to 53.74 ±8.47 D (p <.001). RMS Total and RMS HOAs both showed significance between baseline and follow-up (p <.001) and between treatments in the same follow-up interval (p <.001).
Conclusions: Epithelial removal using t-PTK during CXL results in better visual and refractive outcomes compared with mechanical epithelial debridement. However, further studies are needed to determine the true differences between treatments. | |
