Effects of corneal cross-linking on contrast sensitivity, visual acuity, and corneal topography in patients with keratoconus

Cornea. 2013 May;32(5):591-6. doi: 10.1097/ICO.0b013e31826672e2.


Purpose: 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.

MeSH terms

  • Adolescent
  • Adult
  • Collagen / metabolism*
  • Contrast Sensitivity / physiology*
  • Corneal Stroma / metabolism*
  • Corneal Topography*
  • Cross-Linking Reagents / therapeutic use*
  • Female
  • Humans
  • Keratoconus / drug therapy*
  • Keratoconus / metabolism
  • Keratoconus / physiopathology
  • Male
  • Photochemotherapy
  • Photosensitizing Agents / therapeutic use
  • Prospective Studies
  • Riboflavin / therapeutic use
  • Treatment Outcome
  • Ultraviolet Rays
  • Visual Acuity / physiology*
  • Young Adult


  • Cross-Linking Reagents
  • Photosensitizing Agents
  • Collagen
  • Riboflavin