Combined transepithelial phototherapeutic keratectomy and corneal collagen cross-linking for progressive keratoconus.
OBJECTIVE
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) versus mechanical epithelial debridement.


METHODS
Prospective, comparative, interventional case series.


METHODS
Thirty-four patients (38 eyes) with progressive keratoconus were enrolled.


METHODS
All patients underwent uneventful CXL treatment. Sixteen patients (19 eyes) underwent epithelial removal using t-PTK (group 1) and 18 patients (19 eyes) underwent mechanical epithelial debridement using a rotating brush (group 2) during CXL treatment. Visual and refractive outcomes were evaluated along with corneal confocal microscopy findings preoperatively and at 1, 3, 6, and 12 months postoperatively.


METHODS
Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, and keratometry readings.


RESULTS
No intraoperative or postoperative complications were observed in any of the patients. In group 1, logarithm of the minimum angle of resolution mean UDVA and mean CDVA improved from 0.99 ± 0.71 and 0.30 ± 0.26 preoperatively to 0.63 ± 0.42 (P = 0.02) and 0.19 ± 0.18 (P = 0.008) at 12 months postoperatively, respectively. In group 2, neither mean UDVA nor mean CDVA demonstrated a significant improvement at 12 months postoperatively (P>0.05). In group 1, mean corneal astigmatism improved from -5.84 ± 3.80 diopters (D) preoperatively to -4.31 ± 2.90 D (P = 0.015) at the last follow-up, whereas in group 2 there was no significant difference at the same postoperative interval (P>0.05). No endothelial cell density alterations were observed throughout the follow-up period for both groups (P>0.05).


CONCLUSIONS
Epithelial removal using t-PTK during CXL results in better visual and refractive outcomes in comparison with mechanical epithelial debridement.
Institute of Vision and Optics (IVO), Faculty of Medicine, University of Crete, Heraklion, Crete, Greece. kymionis@med.uoc.gr
George D
GD
Kymionis
Michael A
MA
Grentzelos
George A
GA
Kounis
Vasilios F
VF
Diakonis
Aliki N
AN
Limnopoulou
Sophia I
SI
Panagopoulou
D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003131:Combined Modality Therapy; D003319:Corneal Stroma / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D003646:Debridement / Q000379:methods; D018450:Disease Progression; D019573:Epithelium, Corneal / Q000601:surgery; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D018613:Microscopy, Confocal; D010778:Photochemotherapy; D018903:Photorefractive Keratectomy; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin