scholarly journals Study of Demarcation Line Depth in Transepithelial versus Epithelium-Off Accelerated Cross-Linking (AXL) in Keratoconus

2019 ◽  
Vol 2019 ◽  
pp. 1-4 ◽  
Author(s):  
Yehia Salah ◽  
Kholoud Omar ◽  
Ahmed Sherif ◽  
Sarah Azzam
Keyword(s):  
Clinical Trial ◽  
Anterior Segment ◽  
Cross Linking ◽  
Demarcation Line ◽  
Anterior Segment Oct ◽  
Significant Difference ◽  
Uva Light ◽  
Biomechanical Effect ◽  
Contralateral Eye ◽  
Line Depth

Aim. This is a prospective interventional clinical trial to assess the depth of the demarcation line in transepithelial versus epithelium-off accelerated corneal cross-linking (AXL) in keratoconus patients. Methods. This prospective clinical trial was conducted on 40 eyes of 20 patients. Each patient had transepithelial AXL in one eye and epithelium-off AXL in the contralateral eye applying UVA light with an irradiance of 45 mW/cm2 for 2.4 minutes and 30 mW/cm2 for 4 minutes. The depth of the demarcation line was measured using anterior segment OCT (Topcon 3D OCT-2000) one month postoperative for both eyes. Results. The demarcation line was patchy in 50% of the transepithelial AXL eyes, the other half showing a demarcation line at a mean depth of 183 ± 41.6 μm. In the epithelium-off AXL technique, the demarcation line was well defined in all cases with a mean depth of 219 ± 27.3 μm. There was a statistically significant difference in corneal demarcation line depth between transepithelial and epithelium-off techniques (P = 0.008 and P < 0.05). The shallower demarcation line in the transepithelial group suggests that it is less effective. Conclusion. Based on the depth of the demarcation line, the cross-linking effect of epi-off AXL seems more efficacious than after transepithelial AXL. The future will show if the biomechanical effect will be sufficient to stop progression of keratoconus similarly after standard CXL. This trial is registered with NCT04045626.

scholarly journals Evaluation of Corneal Stromal Demarcation Line after Two Different Protocols of Accelerated Corneal Collagen Cross-Linking Procedures Using Anterior Segment Optical Coherence Tomography and Confocal Microscopy

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Engin Bilge Ozgurhan ◽  
Betul Ilkay Sezgin Akcay ◽  
Yusuf Yildirim ◽  
Gonul Karatas ◽  
Tugba Kurt ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Anterior Segment ◽  
Cross Linking ◽  
Demarcation Line ◽  
Uva Light ◽  
The Mean ◽  
Group 2 ◽  
Collagen Cross Linking ◽  
Corneal Collagen ◽  
Group 1

Purpose. To evaluate the depth of corneal stromal demarcation line using AS-OCT and confocal microscopy after two different protocols of accelerated corneal collagen cross-linking procedures (CXL).Methods. Patients with keratoconus were divided into two groups. Peschke CXL device (Peschke CCL-VARIO Meditrade GmbH) applied UVA light with an intended irradiance of 18.0 mW/cm2for 5 minutes after applying riboflavin for 20 minutes (group 1) and 30 minutes (group 2). One month postoperatively, corneal stromal demarcation line was measured using AS-OCT and confocal microscopy.Results. This study enrolled 34 eyes of 34 patients (17 eyes in group 1 and 17 eyes in group 2). The mean depth of the corneal stromal demarcation line was208.64±18.41 μm in group 1 and240.37±18.89 μm in group 2 measured with AS OCT, while it was210.29±18.66 μm in group 1 and239.37±20.07 μm in group 2 measured with confocal microscopy. Corneal stromal demarcation line depth measured with AS OCT or confocal microscopy was significantly deeper in group 2 than group 1(P<0.01).Conclusion. The group in which riboflavin was applied for 30 minutes showed significantly deeper corneal stromal demarcation line than the group in which riboflavin was applied for 20 minutes.

scholarly journals Corneal Collagen Cross-Linking Mushroom Shape Demarcation Line Profile After Limited Bowman’s Membrane Removal by Phototherapeutic Keratectomy

2015 ◽  
Vol 9 (1) ◽  
pp. 17-19 ◽  
Author(s):  
George D Kymionis ◽  
Michael A Grentzelos ◽  
Nektarios E Klados ◽  
Niki A Xanthopoulou ◽  
Theodore A Paraskevopoulos ◽  
...  
Keyword(s):  
Line Profile ◽  
Anterior Segment ◽  
Cross Linking ◽  
Demarcation Line ◽  
Phototherapeutic Keratectomy ◽  
Early Postoperative Complications ◽  
One Year ◽  
Line Depth ◽  
Collagen Cross Linking ◽  
Corneal Collagen

Purpose :To report a corneal collagen cross-linking (CXL) mushroom shape demarcation line profile after limited Bowman’s membrane removal by phototherapeutic keratectomy (PTK).Methods :Case report.Results :A twenty-one-year-old male with progressive keratoconus underwent mechanical epithelial debridement (at an 8.5 mm zone) followed by PTK (at a 5.0 mm zone and in a 10 μm depth) and CXL. No intra- or early postoperative complications were found. Evaluation of the corneal stromal demarcation line depth using anterior segment optical coherence tomography revealed a mushroom shape profile.Conclusion :It seems that removal of the Bowman’s layer leads to greater depth of the corneal stromal demarcation line.

Biomechanical efficacy of corneal cross-linking using hypoosmolar riboflavin solution

2018 ◽  
Vol 29 (5) ◽  
pp. 474-481 ◽  
Author(s):  
Gregor Wollensak ◽  
Eberhard Spörl
Keyword(s):  
Treatment Group ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Uniaxial Stress ◽  
Cross Linking ◽  
Treatment Groups ◽  
Significant Difference ◽  
Uva Light ◽  
Biomechanical Effect ◽  
Dextran Solution

Purpose: The use of hypoosmolar riboflavin solution has been suggested for cross-linking thin corneas. The aim of this study was to compare the biomechanical efficacy of corneal cross-linking using hypoosmolar dextran-free riboflavin solution (HCXL) versus isoosmolar standard corneal cross-linking treatment (CXL). Methods: A total of 24 postmortem porcine eyes with debrided corneas were subdivided into three treatment groups: Controls, the isoosmolar group with isoosmolar 0.1% riboflavin-20% dextran solution and the hypoosmolar group with dextran-free, 0.1% riboflavin solution. The samples were irradiated with UVA light of 365 nm wavelength and an irradiance of 3 mW/cm² for 30 min (dose 5.4 J/cm²). For the biomechanical measurements, 400-µm-deep anterior corneal flaps were created using a lamellar rotating microkeratome. Uniaxial stress–strain measurements were performed. Results: In the isoosmolar treatment group, stress and Young’s modulus at 8% strain were significantly increased by 67.97%, respectively, 62.62% versus the controls. In the hypoosmolar treatment group, stress and Young’s modulus at 8% strain were significantly increased by 81.21%, respectively, 51.40% versus the controls. There was no significant difference between the iso- and hypoosmolar groups in biomechanical efficacy. On histology, there was no edema in the anterior 200 µm of the corneas after stromal swelling by the hypoosmolar riboflavin solution. Conclusion: Corneal cross-linking using isoosmolar or hypoosmolar riboflavin solution induces a comparable biomechanical effect. This is explained by the localization of the maximum cross-linking effect in the anterior 200 µm of the cornea which are not affected by the swelling effect of hypoosmolar riboflavin solution.

scholarly journals Chemically-Boosted Corneal Cross-Linking for the Treatment of Keratoconus through a Riboflavin 0.25% Optimized Solution with High Superoxide Anion Release

2021 ◽  
Vol 10 (6) ◽  
pp. 1324
Author(s):  
Cosimo Mazzotta ◽  
Marco Ferrise ◽  
Guido Gabriele ◽  
Paolo Gennaro ◽  
Alessandro Meduri
Keyword(s):  
Superoxide Anion ◽  
Hydroxypropyl Methylcellulose ◽  
Anterior Segment ◽  
Preclinical Study ◽  
Cross Linking ◽  
Specular Microscopy ◽  
The Novel ◽  
Power Setting ◽  
Contralateral Eye

The purpose of this study was to evaluate the effectiveness and safety of a novel buffered riboflavin solution approved for corneal cross-linking (CXL) in progressive keratoconus and secondary corneal ectasia. Following the in vivo preclinical study performed on New Zealand rabbits comparing the novel 0.25% riboflavin solution (Safecross®) containing 1% hydroxypropyl methylcellulose (HPMC) with a 0.25% riboflavin solution containing 0.10% EDTA, accelerated epithelium-off CXL was performed on 10 patients (10 eyes treated, with the contralateral eye used as control) through UV-A at a power setting of 9 mW/cm2 with a total dose of 5.4 J/cm2. Re-epithelialization was evaluated in the postoperative 7 days by fluorescein dye test at biomicroscopy; endothelial cell count and morphology (ECD) were analyzed by specular microscopy at the 1st and 6th month of follow-up and demarcation line depth (DLD) measured by anterior segment optical coherence tomography (AS-OCT) one month after the treatment. We observed complete re-epithelization in all eyes between 72 and 96 h after surgery (88 h on average). ECD and morphology remained unchanged in all eyes. DLD was detected at a mean depth of 362 ± 50 µm, 20% over solutions with equivalent dosage. SafeCross® riboflavin solution chemically-boosted corneal cross-linking seems to optimize CXL oxidative reaction by higher superoxide anion release, improving DLD by a factor of 20%, without adverse events for corneal endothelium.

scholarly journals Correlation between central stromal demarcation line depth and changes in K values after corneal cross-linking (CXL)

2018 ◽  
Vol 256 (4) ◽  
pp. 759-764 ◽  
Author(s):  
Niklas Pircher ◽  
Jan Lammer ◽  
Stephan Holzer ◽  
Andreas Gschließer ◽  
Ruth Donner ◽  
...  
Keyword(s):  
Cross Linking ◽  
Demarcation Line ◽  
Line Depth

scholarly journals Optical Coherence Tomography Reveals New Insights into the Accommodation Mechanism

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Mahmoud Mohamed Farouk ◽  
Takeshi Naito ◽  
Kayo Shinomiya ◽  
Hiroshi Eguchi ◽  
Khulood Mohammed Sayed ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Outcome Measures ◽  
Anterior Segment ◽  
Case Series ◽  
Optical Coherence ◽  
Anterior Pole ◽  
Forward Movement ◽  
Anterior Segment Oct ◽  
Lens Thickness ◽  
Significant Difference

Purpose. To evaluate the movement of the anterior and posterior lens poles during naturally stimulated accommodation in children using anterior segment optical coherence tomography (OCT).Methods. This is a prospective, observational, noncomparative case series including 18 eyes of nine children. Analysis of the anterior segment in the accommodated and unaccommodated state (with cycloplegia) was done using anterior segment OCT. The main outcome measures were the position of the anterior and posterior lens poles (in relation to the cornea) and lens thickness (LT).Results. A Statistically significant forward movement of the anterior lens pole and backward movement of the posterior lens pole with an increase in LT were found during accommodation (P<0.001). There was no significant difference between the degree of movement of the anterior lens pole and the posterior lens pole during accommodation (P=0.944).Conclusions. Anterior segment OCT provides a rapid noncontact method for studying accommodation in children. The backward movement of the posterior lens pole during accommodation nearly equals the forward movement of its anterior pole. These data minimize the theoretical hydraulic effect of the vitreous during accommodation, adding more support to the capsular theory of Helmholtz.

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