scholarly journals Molecular processes of corneal collagen cross-linking in keratoconus therapy

2018 ◽  
Vol 4 (1) ◽  
pp. 489-492
Author(s):  
Steven Melcher ◽  
Eberhard Spörl ◽  
Edmund Koch ◽  
Gerald Steiner
Keyword(s):  
Mechanical Stability ◽  
Attenuated Total Reflection ◽  
Secondary Amines ◽  
Cross Linking ◽  
Therapeutic Effects ◽  
Corneal Tissue ◽  
In Situ Experiments ◽  
Cross Links ◽  
Collagen Cross Linking ◽  
Corneal Collagen

AbstractCorneal collagen cross-linking (CXL) with riboflavin and UVA light is a therapeutic procedure to restore the mechanical stability of corneal tissue. The treatment method applies to pathological tissue changes, such as keratoconus. It induces the photochemical formation of new collagen cross-links. Although therapeutic effects are indisputable, the exact molecular process of CXL and how cross-links are formed is still unclear. In this work, Fouriertransform infrared (FT-IR) spectroscopy is used to investigate the cross-linking process. For that purpose, in-situ experiments with porcine corneas are carried out using attenuated total reflection (ATR) spectroscopy. Furthermore, IR micro-spectroscopic imaging in transmission mode is used to investigate thin tissue sections of the cornea and initial approaches for the distinction of cross-linked and untreated tissue by IR microspectroscopic imaging were performed. Multivariate methods are applied to access changes that occur as a result of CXL. It is shown that spectral changes after cross-linking are caused predominantly by an increase of methyl- and methylene groups as well as primary and secondary amines. In addition, a decrease of carbonyl groups could be observed.

scholarly journals Simultaneous Noncentered Photoactivated Chromophore for Keratitis-Corneal Collagen Cross-Linking and Penetrating Keratoplasty for Treatment of Severe Marginal Fusarium spp. Keratitis: A Description of a New Surgical Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Kepa Balparda ◽  
Juan Carlos Mejia-Turizo ◽  
Tatiana Herrera-Chalarca
Keyword(s):  
Penetrating Keratoplasty ◽  
Cross Linking ◽  
Corneal Tissue ◽  
Corneal Perforation ◽  
Fusarium Spp ◽  
Retrospective Case ◽  
Clinical Control ◽  
Collagen Cross Linking ◽  
New Surgical Technique ◽  
Corneal Collagen

The purpose of this article is to describe the use of simultaneous noncentered photoactivated chromophore for keratitis-corneal collagen cross-linking (PACK-CXL) combined with penetrating keratoplasty in the treatment of a severe marginal Fusarium spp. keratitis case with imminent corneal perforation. It is a retrospective case report study; it was performed by collecting clinical data, images, video, and postoperative evaluations. The clinical control of the infection was accomplished, despite difficulties in obtaining antifungal medications due to the patient’s extremely poor socioeconomic status and essentially nonexistent health insurance. We can conclude that combining simultaneous decentered PACK-CXL with centered penetrating keratoplasty appears to be a safe and effective way of treating patients with fungal marginal keratitis with corneal perforation, in which regular penetrating keratoplasty alone would leave fungal elements in the receptor corneal tissue, which would predispose to infection of the graft.

Vitamin B2 in Corneal Surgery—Riboflavin and Collagen Cross-Linking

2012 ◽  
Vol 05 (02) ◽  
pp. 105
Author(s):  
Spencer Thornton ◽  
Keyword(s):  
Collagen Fibrils ◽  
New Method ◽  
Cross Linking ◽  
Corneal Tissue ◽  
Chemical Bonds ◽  
Vitamin B2 ◽  
Corneal Surgery ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Cross-linking of collagen refers to the ability of collagen fibrils to form strong chemical bonds with adjacent fibrils. Corneal collagen cross-linking (CXL) with vitamin B2 activated by ultraviolet offers a new method for stabilization of unstable or weakened corneal tissue in cases of ectasia, dystrophy and irregular post-surgical healing.

scholarly journals Mueller Matrix-Based Approach for the Ex Vivo Detection of Riboflavin-Treated Transparent Biotissue

2021 ◽  
Vol 11 (23) ◽  
pp. 11515
Author(s):  
Lennart Jütte ◽  
Gaurav Sharma ◽  
Dierk Fricke ◽  
Maximilian Franke ◽  
Merve Wollweber ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Ex Vivo ◽  
Measurement Data ◽  
Mueller Matrix ◽  
Cross Linking ◽  
Sample Number ◽  
Non Invasive ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Corneal collagen cross-linking is an established procedure for the treatment of certain eye diseases which is applied to enhance the mechanical stability of such biotissue without deteriorating its functionality. However, being transparent, the optical analysis of the outcome of such treatments is cumbersome and relies on relatively expensive experimental equipment. We aim to apply the Mueller matrix polarimetry for the detection of photo-induced collagen cross-linking in transparent biotissue after treatment with riboflavin and UV irradiation. A simple Mueller matrix polarimetry setup could provide a fast and non-invasive analysis of transparent media to sensitively detect small photo-induced cross-linking effects in biotissue. We demonstrated the current capabilities of the approach on non-planar porcine cornea samples ex vivo. We reported the distinction between untreated and riboflavin-treated samples. The differences observed were correlated with the variation of certain Mueller matrix elements and parameters derived from the decomposition. The measurement data show variation in the cross-linked and non-cross-linked samples, although the effect of the UV treatment on the riboflavin-treated samples was not at the same level of significance yet and needs further investigation. The Mueller matrix measurement represents a promising approach for the detection of the effects of corneal collagen cross-linking. Further studies with a larger sample number are required to validate this approach. In the future, this could enable the reliable and non-invasive detection of photo-induced effects in biotissue and open the possibility for in vivo application, e.g., in eye disease treatment or the detection of scar collagen development.

scholarly journals ZDRAVLJENJE OKUŽB ROŽENICE S PREČNIM POVEZOVANJEM KOLAGENIH VLAKEN

2016 ◽  
Vol 85 (3) ◽  
Author(s):  
Mirna Štabuc Šilih
Keyword(s):  
Antimicrobial Treatment ◽  
Current Data ◽  
Cross Linking ◽  
Bullous Keratopathy ◽  
Ultraviolet A ◽  
Initial Management ◽  
Cross Links ◽  
The Stability ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Corneal collagen cross-linking increases the stability of the cornea through the use of the photosensitive material - riboflavin (vitamin B2) and ultraviolet A radiation. Progressive keratoconus is the most common indication and the frequency of these procedures is increasing worldwide. As cross-links in the cornea are a physiological principle of all connective tissue, additional indications were proposed. These include postrefractive surgery ectasia, bullous keratopathy, and, infectious keratitis.Infectious keratitis can lead to blindness without proper antimicrobial therapy. But even prompt initial management, with appropriate antimicrobial treatment, can be subjected to microorganism sensitivity and resistance.This article presents current data regarding the use of corneal collagen cross-linking in the treatment of corneal infections. This treatment modality may become important, but unanswered questions remain. Larger, prospective comparative studies should give the answers.

Long term results of accelerated corneal collagen cross-linking in pediatric keratoconus

2021 ◽  
pp. 112067212110183
Author(s):  
Yasin Cinar ◽  
Cagla Cilem Han ◽  
Alparslan Sahin ◽  
Zeba A Syed
Keyword(s):  
Visual Acuity ◽  
Corneal Thickness ◽  
University Hospital ◽  
Long Term Results ◽  
Cross Linking ◽  
Distance Visual Acuity ◽  
The Mean ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Purpose: To evaluate the long term visual, refractive, and corneal tomographic outcomes of epithelium-off accelerated corneal collagen cross-linking (ACXL) in the management of pediatric keratoconus (KC). Methods: This retrospective study included patients under 18 years old with progressive KC who underwent ACXL between 2012 and 2019 at Dicle University Hospital. Complete ophthalmic examination was performed including uncorrected distance visual acuity (UDVA), best spectacle-corrected distance visual acuity (CDVA), manifest refraction, and corneal tomography. Evaluations were performed preoperatively and at 6 months intervals postoperatively. Results: Forty-nine eyes of 49 patients were included in the study. The mean age of patients at the time of ACXL was 14.2 ± 1.8 (range: 9.5–17.3) years. Mean follow up was 4.61 ± 1.90 (range: 2.0–8.1) years. The mean LogMAR UDVA improved from 0.94 ± 0.41 to 0.81 ± 0.43, 0.69 ± 0.41, and 0.67 ± 0.33 after 1, 3, and 5 years respectively ( p = 0.001). The mean LogMAR CDVA improved from 0.58 ± 0.36 to 0.46 ± 0.31, 0.34 ± 0.23, and 0.39 ± 0.27 after 1, 3, and 5 years respectively ( p = 0.015). The mean refractive cylinder improved significantly from 6.01 ± 2.07 diopters (D) to 5.46 ± 1.87, 5.38 ± 2.18, and 5.02 ± 2.31 D after 1, 3, and 5 years respectively ( p = 0.005). As compared to preoperative values, steep keratometry and maximum keratometry were not significantly different ( p = 0.805 and 0.448, respectively) following ACXL, while flat keratometry significantly improved after ACXL ( p = 0.012). Although central corneal thicknesses decreased significantly ( p = 0.029), the decrease in thinnest corneal thickness was not statistically significant ( p = 0.205). Conclusion: Epithelium-off ACXL seems to be effective for halting KC progression with long term clinical benefits in pediatric patients.

Sign in / Sign up

Export Citation Format

Share Document