title: Comparison of transepithelial corneal collagen crosslinking with epithelium-off crosslinking in progressive keratoconus.
abstract: OBJECTIVE
  To evaluate the safety and efficacy of transepithelial corneal collagen crosslinking (TE-CXL) as compared to epithelium-off crosslinking (epi-off CXL) in progressive keratoconus.
  
  
  METHODS
  Records of keratoconus patients treated with TE-CXL or epi-off CXL were reviewed retrospectively. Patients were included if they had at least 12months follow-up. Pre- and postoperative measurements of visual acuity, refractive errors, keratometry, corneal topography and pachymetry were assessed and compared.
  
  
  RESULTS
  There was no statistically significant difference between two groups at baseline in terms of demographic, refractive and corneal parameters. Mean maximum cone apex curvature (apical K) increased from 51.62±5. Eighty-four diopters (D) to 53.70±5.49 D in the TE-CXL group (n=17), and decreased from 52.02±4.07 D to 51.22±3.51 in the epi-off CXL group (n=19) at the end of the follow-up period. The difference between two groups was statistically significant (P=0.0002). An increase of≥1D in apical K was observed in two of 19 eyes (11%) in the epi-off CXL group, and 11 of 17 eyes (65%) in TE-CXL group at the last follow-up visit, compared to baseline (P<0.0001). Fourteen patients in the epi-off CXL group exhibited corneal edema that resolved without haze with topical corticosteroid treatment by 4months. No postoperative corneal edema was observed in TE-CXL group.
  
  
  CONCLUSIONS
  Although it is safe and well tolerated, TE-CXL does not effectively halt the progression of keratoconus. Epi-off CXL appears to be effective in stopping progression and even improves corneal parameters.
authors.affiliation: Service d'ophtalmologie, hôpital de Nisa, Istanbul, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Kocak
authors.affiliation: Service d'ophtalmologie, hôpital de Nisa, Istanbul, Turkey; Clinique universitaire d'ophtalmologie, faculté de médecine, université d'Istanbul Medipol, Istanbul, Turkey. Electronic address: aliaydin67@hotmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Aydin
authors.affiliation: Service d'ophtalmologie, hôpital de Nisa, Istanbul, Turkey.
authors.forename: F
authors.initials: F
authors.lastname: Kaya
authors.affiliation: Service d'ophtalmologie, hôpital de Kent, Kutahya, Turkey.
authors.forename: H
authors.initials: H
authors.lastname: Koc
mesh_terms: D000293:Adolescent; D000328:Adult; D003094:Collagen / Q000737:chemistry / Q000187:drug effects*; D003315:Cornea / Q000187:drug effects* / Q000473:pathology; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D018450:Disease Progression; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000473:pathology; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D010778:Photochemotherapy / Q000009:adverse effects; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen
keywords: Corneal collagen crosslinking; Cross-linking du collagène cornéen; Keratoconus; Kératocône; Transepithelial; Transépithélial