title: Corneal collagen cross-linking for the treatment of progressive keratoconus: 3-year prospective outcome.
abstract: OBJECTIVE
  To assess the long-term effects of treatment of progressive keratoconus with ultraviolet A-riboflavin collagen cross-linking (CXL).
  
  
  METHODS
  This was a prospective clinical study.
  
  
  METHODS
  Seventeen eyes of 17 patients with progressive keratoconus were treated with CXL.
  
  
  METHODS
  Patients were examined preoperatively, at week 1, months 1, 3, 6, 9, 12, 24, and 36 after treatment. We assessed uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), refraction, biomicroscopy and fundus appearance, intraocular pressure, endothelial cell density (ECD), corneal topography, minimal corneal thickness (MCT), macular optical coherence tomography, axial length, and corneal biomechanics with the ocular response analyzer.
  
  
  RESULTS
  Comparing the 36-month time point results with pretreatment values, we found that UCVA and BSCVA were unchanged. Steepest meridian keratometry (D) and mean cylinder (D) did not show significant change compared with pretreatment values but showed a slight increase as compared with the 24-month time point (53.9 vs 51.7 vs 52.5, and 10.5 vs 8.1 vs 9.2 before, at 24 months, and at 36 months, respectively). Axial length (mm) showed an elongation trend throughout the follow-up period (24.56 vs 24.61 [p = 0.04] vs 24.71 [p = 0.05], before, at 24 months, and at 36 months, respectively). No significant change was observed in ECD, corneal hysteresis and corneal resistance factor, MCT, or foveal thickness.
  
  
  CONCLUSIONS
  Three-year results after CXL show stable visual acuity, stable corneal thickness, and stable corneal biomechanical parameters. The decreasing trend in keratometry values that was observed during the first 2 years after CXL was no longer evident. Longer follow-up is needed to decide whether it is a first sign of loss of achieved stability and resumption of keratoconus progression.
authors: Department of Ophthalmology, Assaf Harofeh Medical Center; Department of Ophthalmology, Toronto Western Hospital, Toronto, Ont.. Electronic address: doctor.goldich@gmail.com.
authors: Yakov
authors: Y
authors: Goldich
authors: Department of Ophthalmology, Assaf Harofeh Medical Center.
authors: Yaniv
authors: Y
authors: Barkana
authors: Department of Ophthalmology, Assaf Harofeh Medical Center.
authors: Orly
authors: O
authors: Wussuku Lior
authors: Department of Ophthalmology, Kaplan Medical Center.
authors: Arie L
authors: AL
authors: Marcovich
authors: Enaim Refractive Surgery Centers.
authors: Ami
authors: A
authors: Hirsh
authors: Department of Ophthalmology, Assaf Harofeh Medical Center.
authors: Isaac
authors: I
authors: Avni
authors: Department of Ophthalmology, Assaf Harofeh Medical Center.
authors: David
authors: D
authors: Zadok
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000503:physiopathology; D003319:Corneal Stroma / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D016896:Treatment Outcome; D014466:Ultraviolet Rays; D014792:Visual Acuity
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin