Correlation of Demarcation Line Depth With Medium-Term Efficacy of Different Corneal Collagen Cross-Linking Protocols in Keratoconus

Meşen, Ali; Bozkurt, Banu; Kamış, Ümit; Okudan, Süleyman

doi:10.1097/ico.0000000000001733

Cited by 18 publications

(13 citation statements)

References 30 publications

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“…35 Although a larger decrease in corneal thickness was associated with a deeper demarcation line, 22 studies didn't find any significant association between central DDL and refractive or keratometry changes after CXL. [35][36][37][38] Similarly, our study didn't find an association between central DDL and any of the topographic changes that were noticed postoperatively, notably no association with ΔKmax. Therefore, DDL may not be a valid measure of the efficacy of CXL.…”

Section: Corneal Flattening and Depth Of Demarcation Linecontrasting

confidence: 73%

Corneal flattening following collagen crosslinking for keratoconus: Findings at 5-year follow-up

Hoyek

Arej

Rami³

et al. 2020

European Journal of Ophthalmology

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Purpose: To study the corneal flattening effect of cross-linking (CXL) overtime and to look for a potential association with preoperative topographic variables and the central depth of demarcation line (DDL). Methods: 201 eyes of 146 patients (mean age of 31.2 ± 7.3 years) with progressive keratoconus who underwent CXL between June 2007 and December 2012 were enrolled in this retrospective study. Follow-up visits were performed at different time intervals for at least 5 years. Preoperative parameters and depth of demarcation line were collected from LaserVision ophthalmology center in Lebanon. Corneal flattening was defined by a change in postoperative Kmax (ΔKmax) greater than 1.00 D. Results: ΔKmax increased from 50.25% to 61.69%, from first to last follow-up visits. The only factor significantly correlated to ΔKmax during all follow-up visits was preoperative maximum keratometry (Kmax) especially when greater than 50.00 D (OR, 1.92; 95% CI, 1.10–3.34). All eyes showed a corneal demarcation line (mean central depth (DDL): 217.11 ± 26.54 μm), with no statistically significant correlation between DDL and ΔKmax. Conclusion: CXL effect on cornea can be cumulative overtime and delayed flattening occurs in some cases. ΔKmax is positively correlated with preoperative Kmax and no association was found between ΔKmax and DDL. Therefore, DDL may not be a valid measure for the efficacy of CXL.

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Section: Corneal Flattening and Depth Of Demarcation Linecontrasting

confidence: 73%

Corneal flattening following collagen crosslinking for keratoconus: Findings at 5-year follow-up

Hoyek

Arej

Rami³

et al. 2020

European Journal of Ophthalmology

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“…27 The biomechanical implication of the DL depth can be explained by considering that ectasia originates in almost all cases from the posterior float of the cornea. 86 The well-known structure of the human corneal stromal has been revealed by many studies based on X ray diffraction [87][88][89][90][91] . The anisotropy, the orientation, the intersection and the distribution of corneal lamellar structure and collagen fibrils interweaves are not uniform across the thickness of the stroma, but the reinforcing structure characterizes a stronger cornea in the anterior third (160-180µm) and a progressively weaker stroma in the posterior part (over 160-180).…”

Section: Discussionmentioning

confidence: 99%

The meaning of the demarcation line after riboflavin-UVA corneal collagen crosslinking

Mazzotta

Wollensak

Raiskup³

et al. 2019

Expert Review of Ophthalmology

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Since at least two decades, corneal cross-linking by riboflavin and UV-A irradiation stands as an established treatment option of progressive corneal ectasia. More than ten years ago, the histological evaluation of animal corneas and later of human corneas by means of in vivo biomicroscopy and scanning laser confocal microscopy demonstrated in corneas treated with cross-linking procedure the occurrence of a demarcation line running almost parallel to the corneal surface. The feature is a direct consequence of the cross-linking-induced photooxidative modification of the stromal tissue due to riboflavin stromal concentration, light distribution within the corneal stroma, riboflavin activation, oxygen availability and diffusion in the corneal stroma, radicals release, and UV-A exposure time. In this study, the general role of the demarcation line observed after a corneal cross-linking process, in particular its mechanical relevance, clinical consequences, and other various findings in the numerous nowadays available modalities of this treatment, are reviewed objectively.

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“…e conservative treatment modalities, such as spectacles and gas permeable rigid contact lenses, become insufficient for visual rehabilitation in the advanced stages of KC, and 10-20% of patients need corneal transplantation [3]. Wollensak et al [5] introduced the CXL treatment in 2003, which is being considered a standard, minimally invasive, and safe therapeutic option for progressive KC [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. e principle goal of CXL is to stabilize the progression of KC by increasing the mechanical stability of the cornea [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Preliminary Characterization of Predictive Factors of the Visual Change after Epi-On and Epi-Off Corneal Collagen Crosslinking Techniques

Abdelkader

Fernández²,

Sebastián³

et al. 2021

Journal of Ophthalmology

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Purpose. To investigate the potential predictive factors of the visual change achieved with accelerated epi-on and epi-off corneal collagen crosslinking (CXL) in keratoconus. Methods. This retrospective comparative study analyzed 67 eyes treated with an accelerated epithelium-on (epi-on group) and epithelium-off (epi-off group) CXL. The clinical outcomes were evaluated and compared during a 1-year follow-up. Likewise, the relationship of the change achieved with both CXL techniques in the corrected distance visual acuity (CDVA) with different preoperative data was investigated. Results. The mean CDVA change at 3 months postoperatively was −0.04 ± 0.19 and −0.07 ± 0.25 in the epi-on and epi-off groups, respectively ( p = 0.809). In the epi-on group, this change was significantly correlated with the preoperative apical (r = −0.375, p = 0.045) and central corneal thickness (r = −0.402, p = 0.031). In the epi-off group, the CDVA change was significantly correlated with not only the preoperative apical (r = 0.402, p = 0.028) and central corneal thickness (r = 0.367, p = 0.046) but also with some topometric and aberrometric indices (r ≤ −0.374, p ≤ 0.042). Furthermore, the change in CDVA in the epi-on group could be predicted from age, preoperative refractive astigmatism J45 component, anterior corneal asphericity, and posterior corneal high order aberration root mean square ( p = 0.002, R2 = 0.503). In the epi-off group, the CDVA change could be predicted from the preoperative minimum corneal thickness and magnitude of the vertical anterior corneal primary coma component ( p = 0.001, R2 = 0.446). Conclusions. Clearly, different predictive factors of the visual change induced with the accelerated epi-on and epi-off CXL techniques are present, suggesting a different mechanism of action for stiffening the cornea and inducing changes in this structure.

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Correlation of Demarcation Line Depth With Medium-Term Efficacy of Different Corneal Collagen Cross-Linking Protocols in Keratoconus

Abstract: In conventional and accelerated protocols, corneal stromal demarcation line is deeper compared with TE CXL; however, the DD has no correlation with topographic changes, which means that DD is not a direct measure for the efficacy of CXL.

Cited by 18 publications

References 30 publications

Corneal flattening following collagen crosslinking for keratoconus: Findings at 5-year follow-up

Corneal flattening following collagen crosslinking for keratoconus: Findings at 5-year follow-up

The meaning of the demarcation line after riboflavin-UVA corneal collagen crosslinking

Preliminary Characterization of Predictive Factors of the Visual Change after Epi-On and Epi-Off Corneal Collagen Crosslinking Techniques

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