title: Effects of corneal cross-linking on contrast sensitivity, visual acuity, and corneal topography in patients with keratoconus.
abstract: OBJECTIVE
  To assess the effects of corneal collagen cross-linking (CXL) on contrast sensitivity (CS), visual acuity, and corneal topography investigating possible predictors of efficacy.
  
  
  METHODS
  Sixty-eight eyes of 34 patients with progressive keratoconus were enrolled in this prospective study. CXL was performed in one eye and the other eye was left untreated as a control. CS, best spectacle-corrected visual acuity (BSCVA), simulated keratometry in the steepest meridian (SimK-s), mean power in the central 3-mm zone (C-MP), mean power in the paracentral 3- to 5-mm zone (P-MP), maximum keratometric power in the central zone (C-Kmax), and maximum keratometric power in the paracentral zone (P-Kmax) were evaluated at baseline, 40 days, 3 months, 6 months, 1 year, and after 2 years of follow-up.
  
  
  RESULTS
  Treated eyes showed an improvement (P < 0.001) of +0.16 logCS and -0.16 logarithm of the minimum angle of resolution (logMAR) and a reduction in SimK-s of -0.61 diopter (D), C-Kmax -1.11 D, P-Kmax -0.99 D, C-MP -0.39 D, and P-MP -0.30 D. Of the treated eyes, 43.3% had a decrease in C-Kmax greater than 1 D, 50% by 0 to 0.99 D, and 6.7% had an increase of up to +0.89 D. Treated eyes with keratometric apex in the central 3-mm zone (CKA) improved BSCVA -0.19 logMAR and CS +0.19 logCS; whereas in treated eyes with paracentral keratometric apex (PKA), the improvement was -0.13 logMAR and +0.16 logCS.
  
  
  CONCLUSIONS
  CXL with riboflavin and UV-A improved CS and inhibited the progression of keratoconus. As a predictor of treatment efficacy, eyes with CKA showed greater improvement in BSCVA after CXL when compared with eyes with PKA.
authors.affiliation: Department of Ophthalmology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. lamy@ufrj.br
authors.forename: Ricardo
authors.initials: R
authors.lastname: Lamy
authors.forename: Camila F
authors.initials: CF
authors.lastname: Netto
authors.forename: Ricardo G
authors.initials: RG
authors.lastname: Reis
authors.forename: Bruno
authors.initials: B
authors.lastname: Procopio
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.forename: Jay M
authors.initials: JM
authors.lastname: Stewart
authors.forename: Adalmir M
authors.initials: AM
authors.lastname: Dantas
authors.forename: Haroldo V
authors.initials: HV
authors.lastname: Moraes
mesh_terms: D000293:Adolescent; D000328:Adult; D003094:Collagen / Q000378:metabolism*; D015350:Contrast Sensitivity / Q000502:physiology*; D003319:Corneal Stroma / Q000378:metabolism*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D016896:Treatment Outcome; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin