title: Effect of corneal collagen crosslinking on subsequent deep anterior lamellar keratoplasty (DALK) in keratoconus.
abstract: OBJECTIVE
  The purpose was to investigate the impact of ultraviolet light corneal collagen crosslinking (UV-CXL) on the success rate and clinical outcome of subsequent deep anterior lamellar keratoplasty (DALK) in eyes with keratoconus (KC).
  
  
  METHODS
  Medical records of 101 consecutive eyes with KC scheduled for big-bubble DALK surgery were screened retrospectively for details of previously performed UV-CXL, as well as intra- and postoperative complications of DALK surgery. Main outcome measures were intraoperative success rates (big-bubble formation, conversion to penetrating keratoplasty (PK)), postoperative complications, best corrected visual acuity (BCVA), endothelial cell density (ECD), and central corneal thickness (CCT) within 18 months of follow-up.
  
  
  RESULTS
  Out of the 101 KC eyes, eight eyes (7.9%) had a history of previous UV-CXL. Surgical failure, defined as conversion to PK due to macroperforation, occurred in 17 eyes (16.8%) of 93 eyes without and in none with previous UV-CXL (P < .001). Failure to achieve a big-bubble occurred in 37 eyes (40.2%) without previous UV-CXL and in two eyes (25%) with previous UV-CXL. Microperforations of Descemet's membrane were observed in ten eyes (20.7%) without and in 14 eyes (15.2%) with previous UV-CXL (P = .16). No significant differences could be detected for either the postoperative complication rate (P ≥ .18) or the clinical outcome parameters at 18 months follow-up, including BCVA, ECD and CCT (P ≥ .08) for eyes with or without UV-CXL.
  
  
  CONCLUSIONS
  In DALK surgery, prior UV-CXL does not seem to affect the rate of intra- or postoperative complications, the success rate, or its clinical outcome.
authors.affiliation: Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany. friederike.schaub@uk-koeln.de.
authors.forename: Friederike
authors.initials: F
authors.lastname: Schaub
authors.affiliation: Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.
authors.forename: Philip
authors.initials: P
authors.lastname: Enders
authors.affiliation: Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.
authors.forename: Björn O
authors.initials: BO
authors.lastname: Bachmann
authors.affiliation: Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.
authors.forename: Ludwig M
authors.initials: LM
authors.lastname: Heindl
authors.affiliation: Department of Ophthalmology, University of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Cursiefen
mesh_terms: D000328:Adult; D003094:Collagen / Q000494:pharmacology*; D003315:Cornea / Q000187:drug effects / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007640:Keratoconus / Q000175:diagnosis / Q000188:drug therapy / Q000601:surgery*; D015948:Keratoplasty, Penetrating / Q000379:methods*; D008297:Male; D010778:Photochemotherapy / Q000379:methods*; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014792:Visual Acuity
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen
keywords: Big-bubble; Complication; Corneal collagen crosslinking; Deep anterior lamellar keratoplasty; Keratoconus; Macroperforation