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cornea collagen cross-linking

Juan M Bueno, Francisco J Ávila, M Carmen Martínez-García
Corneal cross-linking (CXL) is a surgical procedure able to modify corneal biomechanics and stabilize keratoconus progression. Although it is known that CXL produces changes in corneal collagen distribution, these are still a topic of discussion. Here we quantitatively compare the corneal stroma architecture between two animal models four weeks after in vivo conventional CXL treatment, with second harmonic generation (SHG) imaging microscopy and the structure tensor (ST). The healing stage and the stroma recovery were also analyzed by means of histological sections...
2019: BioMed Research International
Dorota Tarnawska, Maria Jastrzebska, Elwira Chrobak, Monika Kadela-Tomanek, Beata Weglarz, Grzegorz Boryczka, Dariusz Dobrowolski, Elżbieta Chełmecka, Roman Wrzalik
The purpose of the study was to investigate the endogenous fluorescence for the keratoconic cornea in order to analyze changes in the spectra due to the keratoconic stroma abnormalities. Twenty-two corneal buttons obtained from patients with keratoconus (KC, N = 22) at the time of penetrating keratoplasty were used. As a reference, twelve normal corneas (N = 12): ten from the Eye Bank and two from enucleated eyes due to choroidal melanoma were used. The fluorescence excitation/emission matrices (EEM) in the ranges of 250-400/260-600 nm were recorded...
February 5, 2019: Experimental Eye Research
David R Eyre, MaryAnn Weis, Jyoti Rai
Lysyl oxidase-generated intermolecular cross-links are essential for the tensile strength of collagen fibrils. Two cross-linking pathways can be defined, one based on telopeptide lysine aldehydes and another on telopeptide hydroxylysine aldehydes. Since the 1970s it has been accepted that the mature cross-linking structures on the lysine aldehyde pathway, which dominates in skin and cornea, incorporate histidine residues. Here, using a range of MS-based methods, we reexamined this conclusion and  found that telopeptide aldol dimerization is the primary mechanism for stable cross-link formation...
February 7, 2019: Journal of Biological Chemistry
You-Huan Cai, Tai-Xiang Liu, Hai-Xiang Li
AIM: To evaluate the biomechanical stability of the corneal scar treating with riboflavin and ultraviolet A (UVA). METHODS: Totally 86 New Zeal rabbits were divided into control group (group A, n =8) and trauma groups [group B ( n =27), group C ( n =24) and group D ( n =27)]. Then groups B, C and D were divided into three sub-groups according to the time points of sacrifice, i.e. groups Ba, Ca and Da (4wk, n =8); Bb, Cb and Db (6wk, n =8); Bc ( n =11), Cc ( n =8) and Dc (8wk, n =11)...
2019: International Journal of Ophthalmology
Hamid Goodarzi, Khosrow Jadidi, Samiramis Pourmotabed, Esmaeel Sharifi, Hossein Aghamollaei
Corneal disease is considered as the second leading cause of vision loss and keratoplasty is known as an effective treatment for it. However, the tissue engineered corneal substitutes are promising tools in experimental in vivo repair of cornea. Selecting appropriate cell sources and scaffolds are two important concerns in corneal tissue engineering. The object of this study was to investigate biocompatibility and physical properties of the bio-engineered cornea, fabricated from type-I collagen (COL) and gelatin (Gel)...
December 15, 2018: International Journal of Biological Macromolecules
G Y Su, P P Zheng, Y D Su, K Cao, C Gao, Y Zhang, B Li, Q F Liang
Objective: To study the effects of ultraviolet light combined with riboflavin treatment (corneal collagen-crosslinking, CXL) on infectious control and stromal reconstruction of bacterial keratitis. Methods: Experimental Study. A Staphylococcus aureus rabbit keratitis model was established by injecting Staphylococcus aureus broth into the shallow stromal layer of the right eye cornea of New Zealand white rabbits. Forty-four rabbits that successfully established the model were randomly divided into four groups: corneal collagen cross-linking (CXL) group, antibiotic group, CXL+ antibiotic group and untreated group, with 11 rabbits in each group...
December 11, 2018: [Zhonghua Yan Ke za Zhi] Chinese Journal of Ophthalmology
Nina Lidich, Sharon Garti-Levy, Abraham Aserin, Nissim Garti
Microemulsions are widely studied as potential ocular drug delivery vehicles. In the present study we show the versatility of possible use microemulsions as ocular delivery vehicle. The ME is loaded with a hydrophilic drug, riboflavin phosphate (RFP) and a lipophilic, docosahexaenoic acid in triglyceride form (TG-DHA), each separately. These drugs treat keratoconus and dry eye syndrome, respectively. The advantage of using ME loaded with RFP is in overcoming eye epithelium debridement during collagen cross-linking therapy for treatment of keratoconus...
September 27, 2018: Colloids and Surfaces. B, Biointerfaces
Andreas Thorsrud, Anne Marie Hagem, Gunhild Falleth Sandvik, Liv Drolsum
PURPOSE: To compare the effect of corneal collagen cross-linking (CXL) on progressive keratoconus using 0.1% riboflavin with either dextran or methylcellulose as the main supplement. METHODS: In a comparative case series, CXL was performed in 40 patients (40 eyes) using a riboflavin solution containing either dextran (dextran-riboflavin; n = 20) or methylcellulose (methylcellulose-riboflavin; n = 20). Changes in central corneal thickness (CCT), Scheimpflug tomography, maximal keratometry reading (Kmax ), visual acuity (VA) and endothelial cell density (ECD) were recorded...
October 3, 2018: Acta Ophthalmologica
Siân R Morgan, Osamu Hieda, Yoshinori Nakai, Craig Boote, Sally Hayes, Shigeru Kinoshita, Keith M Meek, Andrew J Quantock
Microwave keratoplasty is a thermo-refractive surgical procedure that can correct myopia (short-sightedness) and pathologic corneal steepening by using microwave energy to cause localised shrinkage around an annulus of the cornea leading to its flattening and vision correction. The effects on the corneal extracellular matrix, however, have not yet been evaluated, thus the current study to assess post-procedure ultrastructural changes in an in-vivo rabbit model. To achieve this a series of small-angle x-ray scattering (SAXS) experiments were carried out across whole transects of treated and untreated rabbit corneas at 0...
September 13, 2018: Scientific Reports
Jury Kim, Dong-Beom Ji, Naoaki Takiyama, Jaehyun Bae, Min-Su Kim
OBJECTIVE: To describe the outcome of corneal collagen cross-linking (CXL) combined with superficial keratectomy (SK) as treatment for corneal edema due to corneal endothelial dystrophy (CED) in dogs. ANIMALS STUDIED: Four eyes of four dogs (3 Shih Tzus and 1 English Cocker Spaniel) with corneal edema due to CED were treated with SK and CXL. Two were males, and two were females. PROCEDURE: Depending on corneal thickness, 500-700 μm of edematous cornea was removed by SK...
August 15, 2018: Veterinary Ophthalmology
Yirui Zhu, Ling Li, Peter S Reinach, Yun Li, Chaoxiang Ge, Jia Qu, Wei Chen
Purpose: The purpose of this study was to determine whether corneal collagen crosslinking (CXL) inhibits hemangiogenesis and lymphangiogenesis during acute corneal inflammation in an in vivo rat model. Methods: Inflammatory corneal neovascularization was induced by suture placement into a rat cornea. At day 3 after suture, a CXL protocol using riboflavin and UVA was administered after mechanical epithelial debridement. Hemangiogenesis and lymphangiogenesis were analyzed morphometrically...
July 2, 2018: Investigative Ophthalmology & Visual Science
Yuyu Long, Xuan Zhao, Sa Liu, Min Chen, Bingqian Liu, Jian Ge, Yong-Guang Jia, Li Ren
To improve intraocular transparency of collagen matrices, hydroxypropyl methylcellulose (HPMC) was introduced for the first time into cross-linked collagen to form collagen-HPMC composite membranes. Light transmittance and refractive indices of the membranes are enhanced by incorporation of HPMC in comparison to the control of cross-linked collagen membranes. Maximum light transmittance of the collagen-HPMC membrane was up to 92%. In addition, their permeability of nutrients such as glucose, tryptophan, and NaCl was superior or comparable to that of human corneas...
January 31, 2018: ACS Omega
Betul Seher Uysal, Ozge Sarac, Derya Yaman, Emine Akcay, Nurullah Cagil
PURPOSE: The purpose of the study is to assess changes in optical performance of the cornea in patients with keratoconus following treatment with corneal collagen crosslinking (CXL). MATERIALS AND METHODS: One hundred and eleven eyes of 111 consecutive keratoconus patients with 12-month follow-up after CXL were included. The changes in the visual acuity, manifest refractive errors, and corneal topographic parameters were evaluated. Sirius dual-scanning corneal tomography was used to determine the effectiveness of CXL on each patient's total corneal optical quality; preoperative and 12-month postoperative measurements were analyzed over a 4-mm stimulated pupil and were compared with regards to higher order corneal aberrations (total amount of higher order aberrations [HOAs], vertical coma, horizontal coma, vertical trefoil, oblique trefoil, and spherical aberration), vertical and horizontal modulation transfer function (MTF), and Strehl ratio of point spread function (PSF)...
July 17, 2018: Current Eye Research
Tommy C Y Chan, Jason C K Chan, Yu Meng Wang, Christopher J Rapuano
PURPOSE: To evaluate the history of densitometric data in patients with keratoconus undergoing corneal cross-linking. METHODS: Twenty-two eyes of 22 patients with keratoconus were included. Corneal tomography and densitometry measurements were performed before and after accelerated corneal cross-linking. The duration of corneal haze was defined as the time between cross-linking and densitometry measurements returning to the preoperative value. Survival analysis of corneal haze after cross-linking was performed...
November 2018: Cornea
Hyo Kyung Lee, Jin Suk Ryu, Hyun Jeong Jeong, Mee Kum Kim, Joo Youn Oh
Purpose: To investigate whether the protection of corneal limbus from riboflavin exposure during collagen cross-linking (CXL) prevents limbal epithelial stem cell (LESC) loss. Methods: Ten New Zealand white rabbits received an epithelium-off CXL using an accelerated protocol. Seven days before procedure, 5-bromo-2-deoxyuridine (BrdU) was intraperitoneally injected. During procedure, riboflavin was applied to the corneal surface within a 9 mm diameter retention ring in 5 rabbits, thereby preventing the limbus from riboflavin exposure...
2018: Journal of Ophthalmology
Ali Mahdavi Fard, Rana Daei Sorkhabi, Mojtaba Khazaei, Nader D Nader
PURPOSE: To compare the corneal density before and after accelerated versus conventional corneal cross-linking (CXL). METHODS: Pentacam densitometry and corneal mapping were performed before and 6 months following the randomly assigned intervention. Corneal density was measured over different zones and layers of the cornea by two independent ophthalmologists. Total corneal density was calculated. The patients were followed up for the occurrence of procedure-related and unrelated complication 1 week, 1 month and a final visit around 6 months (180 ± 10 days) after the procedure, during which the corneal density was remeasured and recorded...
June 21, 2018: International Ophthalmology
R Atia, L Jouve, J Knoeri, C Georgeon, L Laroche, V Borderie, N Bouheraoua
Infectious keratitis are a frequent cause of ocular morbidity. Today, new treatments are necessary to combat the emergence of antibiotic resistant germs. Corneal collagen cross-linking has been suggested to treat corneal infectious (PACK-CXL). Its action would be both antimicrobial and protective for the cornea, increasing its biochemical resistence to proteolytic enzymes. In vivo, PACK-CXL might demonstrate good efficacy against bacterial keratitis, contrary to herpetic keratitis for which it is contraindicated...
June 2018: Journal Français D'ophtalmologie
J J Sun, X J Huang, W Y Shi, T Wang
Objective: To evaluate the therapeutic effect of corneal collagen cross-linking (CXL) with preserved corneal epithelial flap and isotonic riboflavin for treatment of keratoconus eyes with thin corneas. Methods: Prospective case-control study. Twenty two eyes of 20 patients (16 males and 4 females, with age of 23.5±4.9), who have been diagnosed with progressive keratoeonus and the comeal stroma thickness of whom were less than 400μm (without the epithelium), were included in this study. Corneal collagen crosslinking was performed under preserved corneal epithelial flap (8...
June 11, 2018: [Zhonghua Yan Ke za Zhi] Chinese Journal of Ophthalmology
Hüseyin Baran Özdemir, Ayşe Kalkancı, Kamil Bilgihan, Pınar Uyar Göçün, Betül Öğüt, Funda Karakurt, Merve Erdoğan
PURPOSE: To compare the antifungal efficacy of corneal collagen cross-linking with photoactivated riboflavin (PACK-CXL) and voriconazole in experimental Fusarium solani and Candida albicans keratitis models. METHODS: Sixty-four corneas of 32 New Zealand rabbits were included and divided into two main groups. Intrastromal injection of Fusarium and Candida suspensions was performed, and it was observed that keratitis was formed on the third day. Both groups were randomly separated into the following four groups: control, PACK-CXL, voriconazole and PACK-CXL combined with voriconazole...
June 4, 2018: Acta Ophthalmologica
Almutez M Gharaibeh, Virginia Saez, Nerea Garcia, Laurent Bataille, Jorge L Alió
PURPOSE: Studying genipin variable concentrations, treatment durations, and delivery methods as a substance to increase corneal stiffness by inducing corneal collagen cross-linking (CXL). MATERIALS AND METHODS: 100 bovine corneas treated with different genipin concentrations (0.1, 0.5, and 1%) and treatment durations (15 min, 40 min, 2 h, and 3 days) through different delivery methods compared to 10 controls treated with riboflavin/UV. Histology examination, enzymatic digestion with collagenase and thermal differential scanning calorimetry were performed on the different samples...
2018: Ophthalmic Research
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