Corneal stromal demarcation line after 4 protocols of corneal crosslinking in keratoconus determined with anterior segment optical coherence tomography

Spadea, Leopoldo; Genova, Lucia Di; Tonti, Emanuele

doi:10.1016/j.jcrs.2018.02.017

Cited by 40 publications

(36 citation statements)

References 15 publications

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“…These findings lend credence to the high oxygen environment indeed augmenting the cross-linking effect in epi-on CXL. The very low effect and absence of demarcation lines with epi-on PiXL in room air is consistent with previous studies demonstrating an inferior effect with epi-on, compared with epi-off CXL (Kobashi et al 2018;Spadea et al 2018). Apparently, the availability of oxygen is a rate-limiting factor for the cross-linking reaction in epi-on CXL.…”

Section: Discussionsupporting

confidence: 91%

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A prospective evaluation of photorefractive intrastromal cross‐linking for the treatment of low‐grade myopia

Fredriksson

Näslund

Behndig

2019

Acta Ophthalmologica

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Purpose To evaluate photorefractive intrastromal cross‐linking (PiXL) treatment for low‐grade myopia, comparing three treatment protocols. Methods Healthy individuals, 25.6 ± 3.6 years of age, with low‐grade myopia underwent epi‐on PiXL with either: 4‐mm zone treated in high oxygen environment (4 mm‐HIGH; n = 15), 4‐mm/room air (4‐mm LOW; n = 6), or 6‐mm/high oxygen (6‐mm HIGH; n = 6). Efficacy was determined by change in uncorrected visual acuity (UCVA), manifest refractive spherical equivalent (MRSE) and corneal curvature (Kmean) over a 12‐month follow‐up. Safety was determined by best spectacle corrected visual acuity (BSCVA), corneal endothelial cell loss and registration of side‐effects. Results Twenty‐seven subjects were included. Due to insufficient effect with the 4‐mm LOW treatment and an unacceptable degree of initial light sensitivity/ocular irritation in the 6‐mm HIGH group, the inclusions to these treatments were stopped after inclusion of 6 patients in each group. The 4‐mm HIGH treatment showed a significantly larger improvement in UCVA (−0.45 ± 0.27 LogMAR) and MRSE (+0.99 ± 0.44 D) at 1, 6 and 12 months compared with the 4‐mm LOW treatment (p < 0.05). At 12 months posttreatment, endothelial cell count and BSCVA were unaltered. More initial side‐effects were noted with the 6‐mm HIGH treatment, compared with the 4‐mm HIGH treatment (p < 0.05). Conclusion Epi‐on PiXL may become a safe and effective non‐ablative treatment for low‐grade myopia. The effect is augmented by high oxygen environment and remains stable for 12 months. The initial ocular irritation is acceptable with a 4‐mm treatment zone. The present results justify further clinical studies on PiXL, including refinements of the technique and long‐term results.

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Section: Discussionsupporting

confidence: 91%

“…; Spadea et al. ). Apparently, the availability of oxygen is a rate‐limiting factor for the cross‐linking reaction in epi‐on CXL.…”

Section: Discussionmentioning

confidence: 97%

A prospective evaluation of photorefractive intrastromal cross‐linking for the treatment of low‐grade myopia

Fredriksson

Näslund

Behndig

2019

Acta Ophthalmologica

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“…To date, the in-vivo correlation between DL depth and corneal biomechanics cannot be estimated by means of a simple relationship. According to Fuchsluger et al 94 the biomechanical parameters of the cornea in healthy and KC eyes, CXL treated or not, can be evaluated by means of ultrahigh-speed Scheimpflug measurements (Corvis ST). A newly introduced parameter, namely the difference between inward applanation length and outward applanation length (A1L -A2L), indicated highly significant differences between CX-linked corneas and untreated KC or healthy corneas.…”

Section: Discussionmentioning

confidence: 99%

“…It follows that the simple geometrical interpretation of the whole dynamic deformation of the cornea, as induced by a soliciting force by using air-puff tonometry devices 94,95 , cannot provide a direct estimate of the actual value of the E-modulus of the cornea, for two main reasons. First, the E-modulus across the cornea is not uniform, in particular in pathologic corneas.…”

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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“…The demarcation line is hyper‐reflective when viewed with OCT, Scheimpflug imaging and on slitlamp biomicroscopy . OCT provides the ability to measure the depth of the demarcation line and has been used as an important outcome parameter when comparing various CXL protocols . The demarcation line usually fades by three months and, in some corneas, is replaced with faint, irregular, hyper‐reflective lines in the deep stroma …”

Section: Corneal Cross‐linkingmentioning

confidence: 99%

Optical coherence tomography imaging in keratoconus

Yip

Chan

2019

Clinical and Experimental Optometry

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Optical coherence tomography (OCT) is being increasingly used as a tool in the diagnosis and management of keratoconus. While elevation-based topography remains essential, there is an expanding role for cross-sectional OCT imaging in the diagnosis of the disease. Images and measurements of corneal thickness, and in particular, epithelial thickness, may be important in diagnosing early cases, and following procedures such as intrastromal corneal ring segments, corneal transplants and corneal collagen cross-linking.

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Corneal stromal demarcation line after 4 protocols of corneal crosslinking in keratoconus determined with anterior segment optical coherence tomography

Abstract: The corneal stromal demarcation line was significantly deeper after epi-off 30-minute standard CXL treatment and after epi-off 9-minute accelerated CXL with high-intensity ultraviolet-A irradiation.

Cited by 40 publications

References 15 publications

A prospective evaluation of photorefractive intrastromal cross‐linking for the treatment of low‐grade myopia

A prospective evaluation of photorefractive intrastromal cross‐linking for the treatment of low‐grade myopia

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

Optical coherence tomography imaging in keratoconus

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