Correlation of Scheimpflug densitometry changes with clinical outcomes after corneal crosslinking

Mathews, Priya; Rojas, Joaquin O. De; Rapuano, Patrick B; Zemsky, Christine; Florakis, George J.; Trokel, Stephen L.; Suh, Leejee H.

doi:10.1016/j.jcrs.2018.05.016

Cited by 15 publications

(28 citation statements)

References 12 publications

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“…Our results showed that one year after CXL, densitometry values remained elevated in the anterior, center and total layers of 0–2 mm and of 2–6 mm rings, and in the center and total layer of 6–10 mm ring compared to the baseline. This pattern is very similar to those studies in which densitometry changes were detected by Scheimpflug imaging [ 12 – 15 ], and suggest that cellular modifications in the central cornea persist at least one year after treatment.…”

Section: Discussionsupporting

confidence: 89%

“…In the literature there are contradictory data on which corneal region is mostly affected by CXL. Most of the studies describe that the highest densitometry change can be measured in the anterior layer [ 12 , 13 ], while the main involvement of the center layer has also been reported [ 15 ]. It might be because the thickness of center corneal layer is not defined in exact µm in Cornea Densito software of Pentacam HR, and differs in every individual.…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have demonstrated increased densitometry values after CXL in keratoconus patients [ 11 – 14 ], mainly in the anterior and middle layers and central rings. Previous studies have already evaluated correlations between densitometry values and postoperative outcomes [ 15 , 16 ], however no preoperative predictive factors of postoperative corneal haze formation have been yet identified after conventional CXL.…”

Section: Introductionmentioning

confidence: 99%

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Factors influencing haze formation and corneal flattening, and the impact of haze on visual acuity after conventional collagen cross-linking: a 12-month retrospective study

et al. 2021

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Background Our aim was to determine associations of pachymetry, keratometry, and their changes with haze formation and corneal flattening after collagen cross-linking, and to analyse the relationship between postoperative haze and visual outcome. Methods Retrospective analysis was performed on 47 eyes of 47 patients with keratoconus using the Pentacam HR Scheimpflug camera before and 1, 3, 6 and 12 months after cross-linking. Corneal backscattered light values in grey scale unit were recorded in the anterior, center and posterior corneal layers and in four concentric rings. Surface area- and thickness-corrected grey scale unit values were assessed with an additional calculation. Friedman test with post hoc Wilcoxon signed-rank test was used to analyse changes in visual acuity, pachymetry, keratometry and densitometry. Spearman’s rank correlation test was used to detect correlations of haze formation and corneal flattening with pachymetry, keratometry and their postoperative change. Generalized estimating equations analysis was used to investigate the influence of densitometry values on postoperative visual acuity after controlling for the effect of preoperative keratometry. Results One year after treatment, significant flattening was observed in maximum and mean keratometry readings (p < 0.001). Significantly increased densitometry values were observed in three central rings compared to baseline (post hoc p < 0.0125). According to receiver operating characteristic curve, densitometry value of the anterior layer of 0–2 mm ring was the most characteristic parameter of densitometry changes after cross-linking (area under the curve = 0.936). Changes in haze significantly correlated with preoperative maximum keratometry (R = 0.303, p = 0.038) and with the changes in maximum keratometry (R = -0.412, p = 0.004). Changes in maximum keratometry correlated with preoperative maximum keratometry (R = -0.302, p = 0.038). Postoperative haze had a significant impact on uncorrected and best corrected distance visual acuity (β coefficient = 0.006, p = 0.041 and β coefficient = 0.003, p = 0.039, respectively). Conclusions Our findings indicate that in more advanced keratoconus more significant corneal flattening effect parallel with haze formation can be observed after cross-linking. Despite significant reduction of keratometry, postoperative corneal haze may limit final visual acuity.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Factors influencing haze formation and corneal flattening, and the impact of haze on visual acuity after conventional collagen cross-linking: a 12-month retrospective study

et al. 2021

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“…Thus, according to our ndigs, nal visual and refractive ourcomes can be achieved until the end of the rst postoperative year. In some recent studies, authors found deterioration in a few percent of involved eyes [29,31]. Similarly, 2.9% of treated eyes had more than two-line-loss 6 years after CXL in our series.…”

Section: Discussionsupporting

confidence: 80%

Long-Term Outcomes of Corneal Collagen Cross-Linking: Results of 6-Years Follow-Up

Csorba

Kiss

Kránitz

et al. 2020

Preprint

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Background: Our aim was to evaluate the long-term effects of conventional epithelium-off corneal cross-linking performed on patients with progressive keratoconus. Methods: A retrospective analysis was performed on 34 eyes of 34 patients with progressive keratoconus underwent conventional cross-linking using Pentacam HR Scheimpflug camera. Visual acuity, spherical equivalent, keratometry, pachymetry and corneal topographic indices were analysed preoperatively and at 1, 3, and 6 years after the surgery. Results: Statistically significant decrease was detected at 1 year in spherical equivalent (p = 0.022), with no significant changes afterward (p =0.616). Uncorrected and best corrected distance visual acuity improved significantly in the first postoperative year (p =0.017 and p= 0.003, respectively), and remained stable with no significant changes at further visits (p = 0.203 and p = 0.336, respectively). Significant decrease of central corneal thickness and thinnest corneal thickness was observed at 1 year (both p <0.001), with additional thinning of thinnest corneal pachymetry up to 3 years (p = 0.01). Maximum keratometry and mean keratometry showed significant, continuous improvement between all consecutive visits over the whole follow-up period (all p-values <0.05). Significant improvement was found in the following 5 topographic indices at 1 year: ISV (p = 0.001), IVA (p = 0.028), KI (p = 0.002), CKI (p <0.001 and Rmin (p <0.001), with further improvement up to 3 years in ISV (p = 0.007), in CKI (p = 0.019) and in Rmin (p = 0.015). Rmin showed more improvement up to the end of follow-up (p <0.001).Conclusions: Conventional epithelium-off corneal cross-linking is effective in halting the progression of keratoconus and in regularization of the anterior corneal surface over a long-term follow-up period up to 6 years.

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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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Correlation of Scheimpflug densitometry changes with clinical outcomes after corneal crosslinking

Cited by 15 publications

References 12 publications

Factors influencing haze formation and corneal flattening, and the impact of haze on visual acuity after conventional collagen cross-linking: a 12-month retrospective study

Factors influencing haze formation and corneal flattening, and the impact of haze on visual acuity after conventional collagen cross-linking: a 12-month retrospective study

Long-Term Outcomes of Corneal Collagen Cross-Linking: Results of 6-Years Follow-Up

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

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