title: [Long-term efficacy of corneal collagen cross-linking in patients with progressive keratoconus].
abstract: OBJECTIVE
  to study the efficacy of corneal collagen cross-linking in patients with progressive keratoconus over longer (up to 2 years) follow-up periods.
  
  
  METHODS
  A total of 52 patients (104 eyes) aged 23-34 years with stage I-III progressive keratoconus were enrolled. Besides routine examinations (automatic refractometry, uncorrected and best corrected visual acuity (UCVA and BCVA) evaluation, pneumatic tonometry), Pentacam keratotopography and pachymetry ("Oculus", Germany) were performed in all cases. Corneal biomechanical properties were assessed with an Ocular Response Analyzer ("Reichert", USA). In all patients cross-linking procedure was carried out in the eye with more advanced keratoconus, the fellow eye being used as the control.
  
  
  RESULTS
  Judging from the results of UCVA and BCVA evaluation, keratotopography, and pachymetry obtained 2 years after the standard corneal cross-linking procedure, stabilization has been achieved in 97% of cases. In the remaining 3% of eyes corresponding parameters declined, although to a lesser extent than in the controls. Indices describing biomechanical properties of the cornea, such as corneal hysteresis, corneal resistance factor, as well as elastonometry results did not differ significantly throughout the whole observation period, which agrees with literature data.
  
  
  CONCLUSIONS
  Corneal collagen cross-linking has been proved capable of stopping keratoconus progression in most of the patients (97%). Further studies with even longer follow-up periods are needed.
authors: Research Institute of Eye Diseases, 11 A, B Rossolimo St., Moscow, Russian Federation, 119021.
authors: I A
authors: IA
authors: Bubnova
authors: Research Institute of Eye Diseases, 11 A, B Rossolimo St., Moscow, Russian Federation, 119021.
authors: A V
authors: AV
authors: Kuznetsov
authors: Research Institute of Eye Diseases, 11 A, B Rossolimo St., Moscow, Russian Federation, 119021.
authors: E V
authors: EV
authors: Zelyanina
authors: Research Institute of Eye Diseases, 11 A, B Rossolimo St., Moscow, Russian Federation, 119021.
authors: I A
authors: IA
authors: Bubnova
authors: Research Institute of Eye Diseases, 11 A, B Rossolimo St., Moscow, Russian Federation, 119021.
authors: A V
authors: AV
authors: Kuznetsov
authors: Research Institute of Eye Diseases, 11 A, B Rossolimo St., Moscow, Russian Federation, 119021.
authors: E V
authors: EV
authors: Zelyanina
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000503:physiopathology*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D018450:Disease Progression; D004548:Elasticity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D012029:Refraction, Ocular / Q000502:physiology*; D013997:Time Factors; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen