Corneal stroma demarcation line after standard and high-intensity collagen crosslinking determined with anterior segment optical coherence tomography

J Cataract Refract Surg. 2014 May;40(5):736-40. doi: 10.1016/j.jcrs.2013.10.029. Epub 2014 Mar 12.


Purpose: To use anterior segment optical coherence tomography (AS-OCT) to compare corneal stroma demarcation line depth after corneal collagen crosslinking (CXL) with 2 treatment protocols.

Setting: Vardinoyiannion Eye Institute of Crete, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece.

Design: Prospective comparative interventional case series.

Methods: Corneal collagen crosslinking was performed in all eyes using the same ultraviolet-A (UVA) irradiation device (CCL-365). Eyes were treated for 30 minutes with 3 mW/cm(2) according to the standard Dresden protocol (Group 1) or for 10 minutes with 9 mW/cm(2) of UVA irradiation intensity (Group 2). One month postoperatively, 2 independent observers measured the corneal stroma demarcation line using AS-OCT.

Results: Sixteen patients (21 eyes) were enrolled. Group 1 comprised 7 patients (9 eyes) and Group 2, 9 patients (12 eyes). The mean corneal stroma demarcation line depth was 350.78 μm ± 49.34 (SD) (range 256.5 to 410 μm) in Group 1 and 288.46 ± 42.37 μm (range 238.5 to 353.5 μm) in Group 2; the corneal stroma demarcation line was statistically significantly deeper in Group 1 than in Group 2 (P=.0058, t test for unpaired data).

Conclusion: The corneal stroma demarcation line was significantly deeper after a 30-minute CXL treatment than after a 10-minute CXL procedure with high-intensity UVA irradiation.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Collagen / metabolism*
  • Corneal Pachymetry
  • Corneal Stroma / metabolism
  • Corneal Stroma / pathology*
  • Cross-Linking Reagents / therapeutic use*
  • Female
  • Humans
  • Keratoconus / drug therapy*
  • Keratoconus / metabolism
  • Male
  • Photosensitizing Agents / therapeutic use
  • Prospective Studies
  • Riboflavin / therapeutic use
  • Tomography, Optical Coherence
  • Ultraviolet Rays
  • Young Adult


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