Comparative evaluation of progression rate in keratoconus before and after collagen crosslinking

Br J Ophthalmol. 2018 Aug;102(8):1109-1113. doi: 10.1136/bjophthalmol-2017-311017. Epub 2017 Nov 9.


Purpose: To compare the rate of disease progression in keratoconus before and after corneal collagen crosslinking (CXL).

Methods: 145 eyes were followed without CXL (no-CXL group) for a median duration of 31 months whereas 45 eyes were followed up for 41 months before (pre-CXL) and after (post-CXL) accelerated, epithelium-off crosslinking. Progression was defined based on significant slope found in linear mixed effect models against time. Swept-source optical coherence tomography was used for measurement of anterior steep keratometry, anterior flat keratometry (Ant Kf), anterior average keratometry (Ant Avg K); posterior steep keratometry, posteriorflat keratometry (Post Kf), posterior average keratometry (Post Avg K) and corneal thickness.

Results: The patients in pre-CXL group were significantly younger (26.3±5.48 years) compared with the patients in no-CXL group (32.7±10.24 years) (P=0.004). Significant differences were observed during baseline examination for all parameters (P≤0.035) between pre-CXL and no-CXL groups except Ant Cyl and Post Cyl. During observation period, statistically significant differences were noted between pre-CXL and no-CXL groups in the progression rate of Ant Kf, Ant Avg K, Post Kf and Post Avg K (P≤0.045). After CXL, the progression rate in post-CXL group was comparable to that in no-CXL group. All corneal parameters remained stable in no-CXL group throughout the follow-up period.

Conclusions: Serial tomographic examination is useful to document disease progression before and after CXL. In our study, a decrease in progression rate of corneal parameters was noted after CXL. In cases with stable corneal parameters over time, careful monitoring can be considered instead of collagen crosslinking.

Keywords: cornea; imaging; treatment other.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Collagen / metabolism*
  • Corneal Pachymetry
  • Corneal Stroma / metabolism
  • Corneal Topography
  • Cross-Linking Reagents*
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Keratoconus / diagnosis*
  • Keratoconus / drug therapy*
  • Keratoconus / metabolism
  • Keratoconus / physiopathology
  • Male
  • Photochemotherapy / methods*
  • Photosensitizing Agents / therapeutic use*
  • Riboflavin / therapeutic use
  • Tomography, Optical Coherence
  • Ultraviolet Rays
  • Visual Acuity / physiology
  • Young Adult


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