title: Accelerated Corneal Collagen Cross-Linking in Thin Keratoconic Corneas.
abstract: OBJECTIVE
  To report the outcomes of accelerated corneal collagen cross-linking in patients with thin corneas (minimum corneal thickness < 400 µm).
  
  
  METHODS
  Thirty-four eyes of 34 patients with a minimum corneal thickness less than 400 µm were included. All patients underwent accelerated corneal collagen cross-linking (irradiance power of 30 mW/cm² at 3 minutes with a total surface dose of 5.4 J/cm²). Uncorrected (UDVA) and corrected distance visual acuity (CDVA), manifest refraction (diopters [D]), and topography were evaluated at baseline and at the 1-, 6-, and 12-month follow-up visit. Endothelial cell density (cells/mm²) was calculated preoperatively and postoperatively at 12 months. The corneal stromal demarcation line was measured using anterior segment optical coherence tomography at 1 month postoperatively.
  
  
  RESULTS
  The mean age of all patients (14 women and 20 men) was 23.08 ± 3.90 years (range: 16 to 29 years). UDVA and CDVA increased but not significantly. UDVA improved from 0.67 ± 0.32 (20/93 ± 20/41 Snellen) to 0.56 ± 0.28 logMAR (20/72 ± 20/38 Snellen) (P = .033) and CDVA improved from 0.49 ± 0.19 (20/61 ± 20/30 Snellen) to 0.42 ± 0.19 logMAR (20/52 ± 20/30 Snellen) (P = .009) at the last follow-up visit. The mean spherical and cylindrical refractions did not significantly change (P = .100 and 0.139, respectively). At the last follow-up visit, the flat keratometry decreased from 47.40 ± 2.52 to 46.95 ± 2.48 D, steep keratometry decreased from 51.04 ± 3.71 to 50.62 ± 3.57 D, and apex keratometry decreased from 57.58 ± 4.49 to 56.26 ± 4.47 D (P = .001, = .0019, = .001, respectively) from baseline. The mean endothelial cell density changed from 2,726.02 ± 230.21 to 2,714.58 ± 218.26 cells/mm² at 12 months postoperatively (P =.086).
  
  
  CONCLUSIONS
  The results of this study revealed that accelerated corneal collagen cross-linking stabilized the progression of keratoconus without a significant endothelial cell density loss during the 12 months of follow-up.
authors.forename: Engin Bilge
authors.initials: EB
authors.lastname: Ozgurhan
authors.forename: Betul Ilkay Sezgin
authors.initials: BI
authors.lastname: Akcay
authors.forename: Tugba
authors.initials: T
authors.lastname: Kurt
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Yildirim
authors.forename: Ahmet
authors.initials: A
authors.lastname: Demirok
mesh_terms: D000293:Adolescent; D000328:Adult; D002452:Cell Count; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004728:Endothelium, Corneal / Q000473:pathology; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012189:Retrospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin