Copenhagen 2016 Registration Programme Exhibitor Information Virtual Exhibition Satellite Meetings Glaucoma Day 2016 Hotel Star Alliance

10 - 14 Sept. 2016, Bella Center, Copenhagen, Denmark

This Meeting has been awarded 27 CME credits


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Effect of pulsed collagen cross-linking technique on the depth of demarcation line in keratoconus

Poster Details

First Author: N. Dervenis UNITED KINGDOM

Co Author(s):    N. Dragoumis   A. Papandroudis   Z. Zachariadis   M. Balidis           

Abstract Details


To assess whether the depth of demarcation line developing after corneal cross linking for keratoconus is associated with the cross-linking protocol used. More specific two pulsed techniques (18 minutes of pulsed UVA and 12 minutes of pulsed UVA) were compared.


This is a case series analysis of keratoconus patients undergoing collagen cross-linking in our ophthalmology unit, Ophthalmica Eye Institute, Thessaloniki, Greece


Non-randomized, prospective case series analysis. Patients with progressive keratoconus were included in the analysis and treated with epithelium-off cross linking. The treatment protocols were: 12 minutes of pulsed UVA – group 1 (20mW/cm2, 7.2J/cm2, pulsed profile: 1 second on, 1 seconds off), 18 minutes of pulsed UVA – group 2 (20mW/cm2, 7.2J/cm2, pulsed profile: 1 second on, 2 seconds off). Topo-guided laser surface ablation was also used were indicated. Independent samples t-test was used to compare the depth of the demarcation line 3 months postop between the two pulsed groups.


39 eyes of 25 subjects were included in the analysis. Group 1 consisted of 19 eyes and group 2 of 20 eyes. The depth of the demarcation line was measured by a trained grader using the Heidelberg Spectralis anterior segment optical coherence tomography software (Heidelberg Engineering, Germany). The mean age of the participants in group 1 was 25.08 years and in group 2 29.14 years (p=0.267). The mean preop k value in group 1 was 45.68D and in group 2 44.80D (p=0.291). The mean preop minimum cornea thickness in group 1 was 480.63μm and in group 2 494.15 μm (p=0.393). The depth of the demarcation line in group 1 was 304.82μm and in group 2 333.75μm (p=0.358).


Our results suggest that the two collagen cross linking techniques give similar outcomes regarding the depth of the demarcation line. The depth of the demarcation line is also comparable to the results reported for the Dresden protocol (the gold-standard for collagen cross linking). Although the significance of the demarcation line has not been fully clarified in the literature, our results support that the two techniques and the Dresden protocol have similar structural outcome and probably similar efficacy in the treatment of keratoconus.

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