title: Effect of corneal cross-linking on contact lens tolerance in keratoconus.
abstract: BACKGROUND
  The aim was to investigate changes in corneal sensation and rigid gas-permeable (RGP) contact lens tolerance after corneal cross-linking (CXL) on patients with keratoconus.
  
  
  METHODS
  Thirty eyes of 30 patients, who were RGP lens intolerant, were treated with CXL. The main outcome measures were corneal sensation evaluation by Cochet-Bonnet esthesiometry, sub-basal nerve fibre assessment by corneal in vivo confocal microscopy and RGP contact lens tolerance evaluation with the Likert scale and wearing time. All eyes were evaluated preoperatively and post-operatively at one, three and six months after CXL procedure.
  
  
  RESULTS
  The mean age was 25.3 ± 6.2 years. Preoperatively, the maximum keratometry (Kmax) in study eyes was 56.89 ± 4.60 D. Six months after CXL, it reduced to 56.03 ± 4.85 D (p = 0.01). Preoperative mean corneal sensation was 0.44 ± 0.05 g/mm2, (range: 0.40 to 0.55); it was significantly decreased at the first month and increased to preoperative values after six months. The sub-basal nerve plexus could not be visualised in 90 per cent of the patients by confocal microscopy at one month post-operatively. Gradual restoration of corneal innervation with almost similar preoperative levels at post-operative month six was noted. There were significant differences in Likert scores between preoperative and third and sixth months after CXL. Likert scale scores correlated significantly with corneal sensitivity.
  
  
  CONCLUSIONS
  It can be concluded that increased RGP contact lens tolerance after CXL may be associated with the potential role of decreased corneal sensitivity and corneal flattening after CXL.
authors.affiliation: Ophthalmology Department, School of Medicine, Erciyes University, Kayseri, Turkey.
authors.forename: Metin
authors.initials: M
authors.lastname: Ünlü
authors.affiliation: Ophthalmology Department, School of Medicine, Gazi University, Ankara, Turkey.
authors.forename: Erdem
authors.initials: E
authors.lastname: Yüksel
authors.affiliation: Ophthalmology Department, School of Medicine, Gazi University, Ankara, Turkey.
authors.forename: Kamil
authors.initials: K
authors.lastname: Bilgihan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003094:Collagen / Q000494:pharmacology*; D003261:Contact Lenses; D003315:Cornea / Q000294:innervation* / Q000473:pathology; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D018613:Microscopy, Confocal; D009416:Nerve Regeneration / Q000187:drug effects; D009882:Ophthalmic Nerve / Q000503:physiopathology*; D010778:Photochemotherapy / Q000379:methods*; D012677:Sensation / Q000502:physiology; D016896:Treatment Outcome; D014466:Ultraviolet Rays; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen
keywords: corneal cross-linking; keratoconus; rigid gas-permeable contact lens; tolerance