title: Corneal cross-linking as a treatment for keratoconus: four-year morphologic and clinical outcomes with respect to patient age.
abstract: OBJECTIVE
  To report the 4-year outcomes of corneal cross-linking (CXL) for progressive keratoconus in a population of different age groups.
  
  
  METHODS
  Retrospective, single-center, nonrandomized clinical study.
  
  
  METHODS
  Four hundred consecutive eyes treated with corneal CXL for progressive keratoconus from April 2006 through April 2010.
  
  
  METHODS
  After removal of the epithelium, the cornea was irrigated for 30 minutes with a solution of 0.1% riboflavin and 20% dextran, followed by irradiation with an ultraviolet A light of 3 mW/cm(2) for 30 minutes.
  
  
  METHODS
  Best-corrected visual acuity (BCVA), sphere and cylinder refraction, corneal topography, Scheimpflug tomography, and aberrometry were assessed at baseline and at 1, 6, 12, 24, 36, and 48 months after corneal CXL treatment. The compiled data were stratified according to age (group A, younger than 18 years; group B, 18-29 years; group C, 30-39 years; and group D, older than 40 years).
  
  
  RESULTS
  Comparative analysis included 400 eyes of 301 patients. Functional results showed a significant increase in BCVA in group A by a mean reduction of -0.11 logarithm of the minimum angle of resolution (logMAR) after 12 months, in group B by a mean reduction of -0.31 logMAR after 36 months, in group C by a mean reduction of -0.33 logMAR after 36 months, and in group D by a mean reduction of -0.26 logMAR after 36 months. Morphologic results showed an analogous regularization of corneal shape with a significant reduction of opposite sector index by a mean value of -0.53 at 12 months in group A, -1.14 at 36 months in group B, -1.10 at 36 months in group C, and -0.55 at 12 months for group D. Optical quality improvement was demonstrated by a mean significant reduction of coma -1.52 μm after 12 months in group A, -1.58 μm after 24 months in group B, -2.57 μm after 36 months for group C, and -0.25 μm after 36 months in group D.
  
  
  CONCLUSIONS
  Outcomes stratified by age indicate the efficacy of corneal CXL in stabilizing the progression of ectatic disease in all age groups and improving the functional and morphologic parameters in select groups. Results indicated better functional and morphologic results in the population between 18 and 39 years of age.
  
  
  BACKGROUND
  Proprietary or commercial disclosure may be found after the references.
authors.affiliation: Humanitas Clinical and Research Center, Rozzano, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Vinciguerra
authors.forename: Mario R
authors.initials: MR
authors.lastname: Romano
authors.forename: Fabrizio I
authors.initials: FI
authors.lastname: Camesasca
authors.forename: Claudio
authors.initials: C
authors.lastname: Azzolini
authors.forename: Silvia
authors.initials: S
authors.lastname: Trazza
authors.forename: Emanuela
authors.initials: E
authors.lastname: Morenghi
authors.forename: Paolo
authors.initials: P
authors.lastname: Vinciguerra
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D017319:Photosensitizing Agents / Q000627:therapeutic use; D012189:Retrospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D016896:Treatment Outcome; D014467:Ultraviolet Therapy / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D012256:Riboflavin