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crosslink cornea

Roy S Rubinfeld, R Doyle Stulting, Glenwood G Gum, Jonathan H Talamo
PURPOSE: To compare the corneal stromal riboflavin concentration and distribution using 2 transepithelial corneal crosslinking (CXL) systems. SETTING: Absorption Systems, San Diego, California, USA. DESIGN: Experimental study. METHODS: The stromal riboflavin concentration of 2 transepithelial CXL systems was compared in rabbit eyes in vivo. The systems were the CXLO (Group 1) and Paracel/Vibex Xtra, containing TRIS and ethylenediaminetetraacetic acid and an isotonic solution of riboflavin 0...
March 8, 2018: Journal of Cataract and Refractive Surgery
Gina L Griffith, Barbara Wirostko, Hee-Kyoung Lee, Lauren E Cornell, Jennifer S McDaniel, David O Zamora, Anthony J Johnson
PURPOSE: The study objective was to test the utilization of a crosslinked, thiolated hyaluronic acid (CMHA-S) film for treating corneal chemical burns. METHODS: Burns 5.5mm in diameter were created on 10 anesthetized, male New Zealand white rabbits by placing a 1N NaOH soaked circular filter paper onto the cornea for 30s. Wounds were immediately rinsed with balanced salt solution (BSS). CMHA-S films were placed in the left inferior fornix of five injured and five uninjured animals...
February 8, 2018: Burns: Journal of the International Society for Burn Injuries
Laura Koivusalo, Jennika Karvinen, Eetu Sorsa, Ilari Jönkkäri, Jari Väliaho, Pasi Kallio, Tanja Ilmarinen, Susanna Miettinen, Heli Skottman, Minna Kellomäki
Corneal blindness is a worldwide problem, plagued by insufficient amount of high-quality donor tissue. Cell therapy using human adipose stem cells (hASCs) has risen as an alternative to regenerate damaged corneal stromal tissue, the main structural and refractive layer of the cornea. Herein we propose a method to deliver hASCs into corneal defects in hyaluronan (HA)-based hydrogels, which form rapidly in situ by hydrazone crosslinking. We fabricated two different HA-based hydrazone-crosslinked hydrogels (HALD1-HACDH and HALD2-HAADH), and characterized their swelling, degradation, mechanical, rheological and optical properties and their ability to support hASC survival...
April 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Hamed Hatami-Marbini, Sandeep M Jayaram
Purpose: The purpose of this study was to characterize the relation between corneal hydration and stiffening effects of the UVA/riboflavin collagen crosslinking treatment and to investigate how artificially swelling the cornea prior to this treatment procedure affects tensile property improvement. Methods: Porcine corneas were collagen crosslinked in vitro at different hydration levels using a number of hypoosmolar and isoosmolar riboflavin solutions. Thickness of the specimens prior to crosslinking was taken as a proxy for their hydration and was used to divide them into different thickness groups...
February 1, 2018: Investigative Ophthalmology & Visual Science
Alina Cantemir, Anisia-Iuliana Alexa, Bogdan Gabriel Galan, Nicoleta Anton, Roxana Elena Ciuntu, Ciprian Danielescu, Dorin Chiselita, Danut Costin
The purpose of this retrospective study was to report the results of iontophoretic corneal collagen crosslinking (I-CXL) with riboflavin and ultraviolet A irradiation in patients affected by keratoconus, each with thinnest pachymetry values of <400 μ (with epithelium) and not treatable using standard epithelium-off technique.Fifteen eyes of 15 patients affected by progressive keratoconus and with thinnest pachymetry values <400 μ underwent I-CXL. The uncorrected (UDVA) and corrected (CDVA) distance visual acuity, maximum and minimum keratometry (K max and K min) readings, corneal thickness at the thinnest point (CTTP), endothelial cell density (ECD), and intraocular pressure (IOP) were assessed before I-CXL, at 1, 3, 6, and 12 months postoperatively...
November 2017: Medicine (Baltimore)
Jaganmohan R Jangamreddy, Michel K C Haagdorens, M Mirazul Islam, Philip Lewis, Ayan Samanta, Per Fagerholm, Aneta Liszka, Monika K Ljunggren, Oleksiy Buznyk, Emilio I Alarcon, Nadia Zakaria, Keith M Meek, May Griffith
Short collagen-like peptides (CLPs) are being proposed as alternatives to full-length collagen for use in tissue engineering, on their own as soft hydrogels, or conjugated to synthetic polymer for mechanical strength. However, despite intended clinical use, little is known about their safety and efficacy, mechanism of action or degree of similarity to the full-length counterparts they mimic. Here, we show the functional equivalence of a CLP conjugated to polyethylene glycol (CLP-PEG) to full-length recombinant human collagen in vitro and in promoting stable regeneration of corneal tissue and nerves in a pre-clinical mini-pig model...
January 17, 2018: Acta Biomaterialia
Jiri Nohava, Michael Swain, Stefan J Lang, Philip Maier, Sonja Heinzelmann, Thomas Reinhard, Philipp Eberwein
UVA-crosslinking is used for treatment of corneal diseases such as keratoconus in order to stabilize the corneal tissue by crosslinking of the collagen fibers. It has been shown that the crosslinking treatment leads to a stiffening of the central corneal tissue. However, knowledge of lateral extent of the corneal stiffening as well as a systematic study of the mechanical response of human cornea is still missing. In our study we measured the stiffness (elastic modulus) of the anterior surface of healthy and crosslinked human corneas by instrumented indentation using a spherical indenter...
January 10, 2018: Journal of Biomedical Materials Research. Part A
Bushra Akbar, Rana Intisar-Ul-Haq, Mazhar Ishaq, Ayesha Fawad, Sabahat Arzoo, Kashif Siddique
PURPOSE: The purpose of this study is to compare the safety and efficacy of transepithelial corneal crosslinking (CXL) with epithelium-off crosslinking (epithelium-off CXL) in the treatment of progressive keratoconus in adult Pakistani population. MATERIALS AND METHODS: Sixty-four eyes of 64 consecutive patients of progressive keratoconus were included in this quasi-experimental study. Thirty-two eyes received transepithelial CXL with Peschke TE (0.25% riboflavin (Vitamin B2), 1...
October 2017: Taiwan Journal of Ophthalmology
Sabine Kling, Arthur Hammer, Emilio A Torres Netto, Farhad Hafezi
Purpose: We studied changes in gene transcription after corneal crosslinking (CXL) in the rabbit cornea in vivo and identified potential molecular signaling pathways. Methods: A total of 15 corneas of eight male New-Zealand-White rabbits were de-epithelialized and equally divided into five groups. Group 1 served as an untreated control. Groups 2 to 5 were soaked with 0.1% riboflavin for 20 minutes, which in Groups 3 to 5 was followed by UV-A irradiation at a fluence of 5...
December 2017: Translational Vision Science & Technology
Staffan Schedin, Per Hallberg, Anders Behndig
A numerical 3D ray tracing model was used to evaluate the long-term visual effects of two regimens of corneal crosslinking (CXL) treatment of 48 patients with the corneal degeneration keratoconus. The 3D ray tracing analyses were based on corneal elevation data measured by Scheimpflug photography. Twenty-two patients were treated with standard CXL applied uniformly across the corneal surface, whereas 26 patients underwent a customized, refined treatment only at local zones on the cornea (photorefractive intrastromal CXL; PiXL)...
December 10, 2017: Applied Optics
Joshua N Webb, Johnny P Su, Giuliano Scarcelli
PURPOSE: To quantify corneal mechanical changes induced by corneal crosslinking (CXL) procedures of different ultraviolet-A (UVA) intensity and exposure time using Brillouin microscopy. SETTINGS: University of Maryland, College Park, Maryland, USA. DESIGN: Experimental study. METHODS: Porcine cornea samples were debrided of epithelia and soaked with riboflavin 0.1% solution. Samples were exposed to a standard 5.4 J/cm2 of UVA radiation with varying intensity and exposure time as follows: 3 mW/cm2 for 30...
November 2017: Journal of Cataract and Refractive Surgery
Hanan Mofty, Khaled Alzahrani, Fiona Carley, Sophie Harper, Arun Brahma, Leon Au, Debbie Morley, M Chantal Hillarby
Purpose: The purpose of this study was to assess UV corneal crosslinking (CXL) treatment outcomes for keratoconus by evaluating the corneal regularity in patients through follow-up using the Oculus Pentacam. Patients and methods: A total of 18 eyes from CXL patients with keratoconus were studied before and after CXL treatment, and six eyes from six patients who were not treated with CXL served as controls. Treated patients had Pentacam images taken before CXL treatment and regularly 3 months post treatment up to the 12th month...
2017: Clinical Ophthalmology
Chameen Samarawickrama, Ayan Samanta, Aneta Liszka, Per Fagerholm, Oleksiy Buznyk, May Griffith, Bruce Allan
PURPOSE: To describe the use of collagen-based alternatives to cyanoacrylate glue for the sealing of acute corneal perforations. METHODS: A collagen analog comprising a collagen-like peptide conjugated to polyethylene glycol (CLP-PEG) and its chemical crosslinker were tested for biocompatibility. These CLP-PEG hydrogels, which are designed to act as a framework for corneal tissue regeneration, were then tested as potential fillers in ex vivo human corneas with surgically created full-thickness perforations...
November 22, 2017: Cornea
Ti Wang, Lu Zhu, Jingyin Zhu, Yinbo Peng, Nianci Shen, Yan Yu, Min Yao
BACKGROUND AND PURPOSE: The purpose of this study was to investigate the subacute effects of Rose Bengal (RB) and 532 nm green light-induced photochemical crosslinking (RB-PCL) on rabbit thin corneal stability and safety in vivo. MATERIALS AND METHODS: Rabbit thin corneal models with 250 μm thickness were created by photorefractive keratectomy surgery. Photochemical crosslinking with green light (wavelength 532 nm) at an illumination intensity of 0.4 W/cm(2) for 250 s (100 J/cm(2) ) was performed, followed by antibiotic treatment and slit lamp monitoring for four weeks...
November 2, 2017: Lasers in Surgery and Medicine
Samantha M Bradford, Eric R Mikula, Dongyul Chai, Donald J Brown, Tibor Juhasz, James V Jester
The purpose of this study was to develop and test a nonlinear optical device to photoactivate riboflavin to produce spatially controlled collagen crosslinking and mechanical stiffening within the cornea. A nonlinear optical device using a variable numerical aperture objective was built and coupled to a Chameleon femtosecond laser. Ex vivo rabbit eyes were then saturated with riboflavin and scanned with various scanning parameters over a 4 mm area in the central cornea. Effectiveness of NLO CXL was assessed by evaluating corneal collagen auto fluorescence (CAF)...
October 1, 2017: Biomedical Optics Express
Bahar Aslan, Selcan Guler, Atakan Tevlek, Halil Murat Aydin
Corneal tissue engineering efforts to obtain corneal tissue matrices through various types of materials for the replacement of damaged tissues. In this study, three different corneal constructs were prepared and evaluated in terms of morphological, optical, and biological characteristics. Type-I collagen was used to obtain collagen foam scaffolds through dehydrothermal crosslinking, while poly(l-lactic acid) (PLLA) was used to produce both random and aligned oriented electrospun corneal constructs. Bovine corneas were decellularized as third matrix...
October 12, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Michael Samsom, Myrto Korogiannaki, Lakshman N Subbaraman, Heather Sheardown, Tannin A Schmidt
Contact lens friction significantly correlates with subjective comfort. Hyaluronan (HA) and proteoglycan 4 (PRG4) are natural boundary lubricants present in the body. The objective of this study was to assess the effect of crosslinked HA into the bulk of model contact lens materials pHEMA, pHEMA/TRIS, and DMAA/TRIS on surface wettability, protein sorption, and boundary lubricating properties at a material-cornea biointerface, both alone and synergistically with PRG4 in solution. Surface wettability was assessed by water contact angle measurement, protein sorption by lysozyme sorption assay, and boundary lubricating properties using an in vitro friction test method...
September 15, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Zackery Oakey, Kevin Thai, Sumit Garg
Introduction: The cornea may become infected and perforated after epithelium-on collagen crosslinking. Case presentation: A healthy 33-year-old male who underwent corneal collagen crosslinking in both eyes developed a purulent keratitis and bilateral corneal perforations, requiring bilateral penetrating keratoplasties. He was exposed to methicillin resistant staphylococcus aureus (MRSA) by a family member with a tracheostomy and was treated with MRSA-directed antibiotics. After prolonged recovery and treatment of his infection, he had acceptable but limited uncorrected visual acuity, with excellent corrected visual acuity...
2017: GMS Ophthalmology Cases
Keyton Clayson, Xueliang Pan, Elias Pavlatos, Ryan Short, Hugh Morris, Richard T Hart, Jun Liu
Factors governing the steady-state IOP have been extensively studied; however, the dynamic aspects of IOP are less understood. Clinical studies have suggested that intraocular pressure (IOP) fluctuation may be associated with glaucoma risk. This study aims to investigate how stiffening of corneoscleral biomechanical properties affects IOP spikes induced by rapid microvolumetric change. Porcine eyes (n = 25 in total) were subjected to volumetric infusions before and after external treatment of a circular area (11 mm diameter) in either the central cornea or posterior sclera...
December 2017: Experimental Eye Research
Yongliang Lin, Qinxiang Zheng, Shanshan Hua, Yongchun Meng, Wei Chen, Yifei Wang
This study aims to develop a cross-linked decellularized porcine corneal graft (cDPC) as a substitute for lamellar donor corneas and to evaluate the feasibility of using cDPC to treat fungal keratitis. The cDPC was prepared by decellularization, chemical crosslinking and γ-ray irradiation. Transparency, effectiveness of decellularization and biomechanical strength of cDPC were evaluated. The safety and efficacy of using cDPC to treat fungal keratitis were evaluated in the rabbit model. The transparency of cDPC was similar to that of a native porcine cornea (NPC), and no intact cells were observed in cDPC except for an insignificant amount of residual shrinking cellular nucleus...
August 30, 2017: Scientific Reports
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