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Louis Lhuillier, Naïla Houmad, Mohamed Zaidi, SOT Maxime, Alix EHRHARDT, adina agapie, Oualid Guechi, Piotr Krawczyk, Huong Duong Nguyen Viet, Jean-Marc Perone; Stromal demarcation line: is it predictive for Cross-Linking efficiency?. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2901.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the association between stromal demarcation line after collagen crosslinking (CXL) for progressive keratoconus and mid-term (6 month) refractive, topographic and clinical outcomes of CXL.
All consecutive patients treated with CXL between March 2014 and March 2015 were included. They all underwent the same procedure: accelerated-CXL protocol (10 minutes UVA irradiation with 9 mW/cm2 intensity), irradiation device (IROC UV-X™ 2000, Medeuronet). One month after the procedure, AS-OCT examination was performed in all patients (RS-3000, NIDEK). The visibility of the stromal demarcation line was scored (0: not visible line; 1: visible line, but measurement not clearly defined; 2: clearly visible line) and its depth was measured centrally at anytime it was possible. Changes in best corrected visual acuity (BCVA), spherical equivalent (SE), Kmax and thinnest pachymetry, were studied preoperatively and at 6 months.
36 eyes (29 patients) with progressive keratoconus were included mean age was 26.1 ± 10.4 years.One month after CXL, a stromal demarcation line was visible for 28 patients (77.8%) (grade 2 : 15, 41.7% and grade 1 : 13, 36.1%) and not visible ( grade 0) for 8 (22.2%) patients. Mean depth of the corneal stromal demarcation line was 342.3 ± 58.5 μm (range 226-440μm).Six month after CXL, the study showed : a significant improvement in BCVA ( preoperative : 0.5LogMar ±0.2 vs postoperative 0.39LogMar ±0.2 , p = 0.031) and SE ( preoperative -6.46 D ±2.1 vs postoperative 5.42D± 2.1 , p = 0.027) ; a significant decrease in thinnest pachymetry ( preoperative : 451.6 µm ± 30.8 vs postoperative 421µm ± 46.9, p = 0.043). No significant change for Kmax (preoperative: 58.1 D ± 5.4 vs postoperative 57.8 ± 4.5, p=0.35).Neither the visibility of the stromal line nor its depth was significantly associated with post-operative changes in Kmax, SE, BVCA or pachymetry (p>0.05).This study tends to show that preoperatively stepper and thinner corneas were associated with a more visible line: Kmax = 58.3 ± 5.5D (visible) vs 54.5 ± 5.8D (not visible line) p=0.051 ; thinnest pachymetry = 451.2 ±34.9µm vs 477.1 ± 26.2µm, p= 0.059.
In our study neither the visibility of the stromal line nor its depth was significantly associated with post-operative changes in Kmax, SE, BVCA or pachymetry (p>0.05). The stromal demarcation line was not predictive for CXL efficiency 6 month after the procedure.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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