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Comparison of accelerated and standard corneal cross-linking protocols in the treatment of progressive keratoconus

Poster Details

First Author: C.Rodrigues PORTUGAL

Co Author(s):    M. Leitao   M. Marques   D. Cabral   S. Alves   H. Nogueira        

Abstract Details


To compare the anatomic and functional outcomes of standard (Dresden protocol) and accelerated corneal cross-linking protocols in the treatment of progressive keratoconus


Retrospective longitudinal observational study of consecutive patients with progressive Keratoconus submitted to Cross-linking


Enrolled 51 eyes in standard protocol group(G1) and 17 eyes in accelerated protocol group(G2). Patients were treated with riboflavin and ultraviolet A(UVA) 3mW/cm2 during 30 minutes (G1) and 9mW/cm2 during 10 minutes (G2). Patients were evaluated at last visit before Cross-linking(baseline) and 1 year postoperatively. All patients had a complete ophthalmic examination, including subjective refraction, visual acuity(VA) and corneal topography using Ziemer GALILEI G2®. We use MeanK, SteepK, Central Corneal thickness(CCT), Thinnest Corneal thickness(ThCT), topography astigmatism(ASTG) and I-S value(I-S) as anatomic parameters and VA as functional parameter. A level of significance p=0.05 was considered


In Baseline there were no significant differences between the two groups in age [G1:20,50σ4,22 and G2:22,00σ6,29], MeanK [G1:45,84σ2,66 and G2:46,98σ2,30], SteepK [G1:47,40σ2,81; G2:48,43σ2,30], CCT [G1:505σ30,95; G2:518σ44,29], ThCT [G1:478σ33,55; G2:480σ59,93], I-S [G1:8,28σ3,43; G2:8,75σ3,68], and VA [G1:0,50 σ0,25; G2: 0,6σ0,4]. At 1 year visit there were a statistical significant difference only in ThCT [p=0.008; G1:15 µm (P25-75:25–15) and G2:6 µm (P25-75:15–1)], in I-S [p=0,006; G1: -0,22 (P25-75: -1,60–0,39) and G2:0,46 (P25-75: -0,17–1,60)] and VA [p=0,026; G1: 0,1 (P25-75:0,0–0,2) and G2: 0,0 (P25-75:0,0– -0,1)]


The two cross-linking prolocols had similar corneal flattening but Dresden achieved a higher increased in ThCT (15µm versus 6µm), a reduction in I-S and a better functional outcome with most patients in G1 gaining at least one line in visual acuity, while in the accelerated group most patients maintain the same vision or loss one line. Our hypothesis is that I-S reduction may improve refractive aberration and so be related to the G1 vision improvement. A long-term follow-up is necessary to confirm Dresden protocol superiority.

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