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Raiskup F, Herber R, Lenk J, Pillunat LE, Spoerl E. Crosslinking with UV-A and riboflavin in progressive keratoconus: From laboratory to clinical practice - Developments over 25 years. Prog Retin Eye Res 2024; 102:101276. [PMID: 38830532 DOI: 10.1016/j.preteyeres.2024.101276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024]
Abstract
Changes in the biomechanical and biochemical properties of the human cornea play an important role in the pathogenesis of ectatic diseases. A number of conditions in primarily acquired (keratoconus or pellucid marginal degeneration) or secondarily induced (iatrogenic keratectasia after refractive laser surgeries) ectatic disorders lead to decreased biomechanical stability. Corneal collagen cross-linking (CXL) represents a technique to slow or even halt the progression of ectatic pathologies. In this procedure, riboflavin is applied in combination with ultraviolet A radiation. This interaction induces the production of reactive oxygen species, which leads to the formation of additional covalent bonds between collagen molecules and subsequent biomechanical corneal strengthening. This procedure is so far the only method that partially interferes etiopathogenetically in the treatment of ectatic diseases that slows or stops the process of corneal destabilization, otherwise leading to the need for corneal transplantation. Besides, CXL process increases markedly resistance of collagenous matrix against digesting enzymes supporting its use in the treatment of corneal ulcers. Since the discovery of this therapeutic procedure and the first laboratory experiments, which confirmed the validity of this method, and the first clinical studies that proved the effectiveness and safety of the technique, it has been spread and adopted worldwide, even with further modifications. Making use of the Bunsen-Roscoe photochemical law it was possible to shorten the duration of this procedure in accelerated CXL and thus improve the clinical workflow and patient compliance while maintaining the efficacy and safety of the procedure. The indication spectrum of CXL can be further expanded by combining it with other vision-enhancing procedures such as individualized topographically-guided excimer ablation. Complementing both techniques will allow a patient with a biomechanically stable cornea to regularize it and improve visual acuity without the need for tissue transplantation, leading to a long-term improvement in quality of life.
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Affiliation(s)
- Frederik Raiskup
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
| | - Robert Herber
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Janine Lenk
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Lutz E Pillunat
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Eberhard Spoerl
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
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Osipyan GA, Khraistin H, Jourieh M. Collagen cross-linking beyond corneal ectasia: A comprehensive review. Indian J Ophthalmol 2024; 72:S191-S202. [PMID: 38271415 DOI: 10.4103/ijo.ijo_1507_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 11/19/2023] [Indexed: 01/27/2024] Open
Abstract
The history of corneal cross-linking (CXL) dates back to 2003 when some German scientists investigated possible treatments to harden the corneal structure to increase its resistance in ectatic corneal diseases. Nowadays, CXL is considered the most effective therapy in ectatic corneal diseases due to its proven efficacy in hardening the cornea, thus halting the development of the disease. Since 2003, CXL applications have dramatically expanded and have been implemented in several other areas such as infectious keratitis, corneal edema, and before performing keratoplasty for various purposes. Moreover, several irradiation patterns are being studied to correct refractive errors, taking into account the corneal refractive changes that occur after the procedure. Currently, scleral cross-linking is also being investigated as a potential therapy in cases of progressive myopia and glaucoma. In this article, we provide a comprehensive overview of the available applications of cross-linking in nonectatic ocular conditions and highlight the possible future indications of this procedure.
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Affiliation(s)
- Grigory A Osipyan
- Department of Corneal Pathology, Krasnov Research Institute of Eye Diseases, Moscow, Russia
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Al-Mahrouqi H, Cheung IMY, Angelo L, Yu TY, Gokul A, Ziaei M. Therapeutic non-ectasia applications of cornea cross-linking. Clin Exp Optom 2023; 106:580-590. [PMID: 36690333 DOI: 10.1080/08164622.2022.2159790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 08/28/2022] [Accepted: 10/10/2022] [Indexed: 01/25/2023] Open
Abstract
Corneal cross-linking is a photopolymerization technique traditionally used to strengthen corneal tissue. Corneal cross-linking utilizes riboflavin (vitamin B2) as a photosensitizer and ultraviolet-A light (UVA) to create strong covalent bonds within the corneal stroma, increasing tissue stiffness. Multiple studies have demonstrated corneal cross-linking's effectiveness in treating corneal ectasia, a progressive, degenerative, and non-inflammatory thinning disorder, as quantified by key tomographic, refractive, and visual parameters. Since its introduction two decades ago, corneal cross-linking has surpassed its original application in halting corneal ectatic disease and its application has expanded into several other areas. Corneal cross-linking also possesses antibacterial, antienzymolytic and antioedematous properties, and has since become a tool in treating microbial keratitis, correcting refractive error, preventing iatrogenic ectasia, stabilising bullous keratopathy and controlling post keratoplasty ametropia. This review provides an overview of the current evidence base for the therapeutic non-ectasia applications of cornea cross-linking and looks at future developments in the field.
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Affiliation(s)
| | | | - Lize Angelo
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Tzu-Ying Yu
- Department of Ophthalmology, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Akilesh Gokul
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Mohammed Ziaei
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
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Angelo L, Gokul Boptom A, McGhee C, Ziaei M. Corneal Crosslinking: Present and Future. Asia Pac J Ophthalmol (Phila) 2022; 11:441-452. [PMID: 36094381 DOI: 10.1097/apo.0000000000000557] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 07/08/2022] [Indexed: 11/25/2022] Open
Abstract
Keratoconus is a progressive corneal thinning disorder that can lead to vision loss. In the last 2 decades, corneal crosslinking (CXL) has emerged as an effective method to halt the progression of keratoconus and reduce the number of patients requiring keratoplasty. The procedure has been adopted globally and has evolved to become a part of combination treatments to regularize the cornea and improve visual outcomes. CXL has even been extrapolated in managing other ocular pathologies such as progressive myopia, infectious keratitis, and bullous keratopathy. This review aims to summarize the current role of CXL in keratoconus and its alternative uses, and provide insights into future developments in this fast-developing field.
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Affiliation(s)
- Lize Angelo
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Miao Y, Liu J, Akella SS, Wang J, Li S, Chuck RS, Zhang C. Changes in Rat Scleral Collagen Structure Induced by UVA-Riboflavin Crosslinking at Various Tissue Depths in Whole Globe Versus Scleral Patch. Transl Vis Sci Technol 2022; 11:2. [PMID: 35913416 PMCID: PMC9351595 DOI: 10.1167/tvst.11.8.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate structural changes in scleral collagen fibers at various tissue depths before and after photosensitized crosslinking (CXL) both isolated scleral patch versus whole globe using second-harmonic generation (SHG) imaging. Methods Scleral tissues were harvested from Sprague-Dawley rats and separated into three groups: untreated sclera (control), full-thickness scleral patch for CXL (Free Scleral CXL group), and sclera in intact globe for CXL (Globe CXL group). The CXL groups were soaked in 0.1% riboflavin and irradiated with 365 nm ultraviolet-A light (power, 0.45 mW/cm2) for 30 minutes. SHG images were acquired every 5 µm between 10 and 60 µm from the outer scleral surface. Collagen fiber waviness was calculated as the ratio of the total length of a traced fiber and the length of a straight path between the fiber ends. Results In the Free Scleral CXL group, collagen waviness was significantly increased compared to the control group at 35 to 50 µm (P < 0.05). In the Globe CXL group, collagen waviness was decreased compared to control at all depths with statistical significance (P < 0.05) achieved from 10 to 45 µm. Conclusions Depending upon its initial state (i.e., free scleral patch versus mechanically loaded intact globe under pressure), collagen may experience different structural changes after CXL. In addition, the extent of the CXL effects may vary at different depths away from the surface. Translational Relevance Understanding the CXL effects on collagen structure may be important in optimizing the scleral crosslinking protocol for future clinical applications such as preventing myopic progression.
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Affiliation(s)
- Yuan Miao
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China.,Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Juan Liu
- Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA.,Department of Ophthalmology, People's Hospital of Ningxia Hui Autonomous Region, Yinchuan, Ningxia, China
| | - Sruti S Akella
- Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jessie Wang
- Department of Ophthalmology & Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Shaowei Li
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China
| | - Roy S Chuck
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China
| | - Cheng Zhang
- Aier School of Ophthalmology, Central South University, Changsha, Hunan, China
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Lammer J, Laggner M, Pircher N, Fischinger I, Hofmann C, Schmidinger G. Endothelial Safety and Efficacy of Ex Vivo Collagen Cross-linking of Human Corneal Transplants. Am J Ophthalmol 2020; 214:127-133. [PMID: 32171767 DOI: 10.1016/j.ajo.2020.02.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE To assess endothelial safety and efficacy of ex vivo corneal collagen cross-linking (CXL) in human corneal transplants stored in 2 different culture media. DESIGN Fellow-eye controlled laboratory study of ex vivo human donor corneas. METHODS Three sets of paired human donor corneas, 5 pairs each, were stored in organ culture medium before deswelling either at 31 C or at room temperature. One eye of each pair was cross-linked by 0.1% riboflavin in hydroxylpropyl methylcellulose (HPMC) instillation for 10 minutes followed by 10 minutes of ultraviolet-A (9 mW/cm2) irradiation while contralateral eyes served as controls. In Set 1, endothelial cell densities were determined. In Set 2, paired samples were assigned to the 2 deswelling media and CXL efficacy was assessed comparing to untreated controls using collagenase-A-assisted enzymatic digestion. In Set 3, biomechanical testing was performed in the eye pairs (treated vs control) by stress/strain measurements. RESULTS There was no difference in endothelial cell counts between CXL samples and controls (P = .21). No statistically significant difference in digestion dynamics was found between tissues stored in the 2 different culture media. Complete enzymatic digestion was slowed down by 3 hours in the cross-linked samples (P = .036). Stress needed for a 12% strain was increased by 34% in the treatment group compared to control (P = .04). CONCLUSIONS Ex vivo CXL of human donor tissue is an effective and safe procedure with no difference regarding efficacy between 2 commercially available deswelling media. Biochemical and biomechanical resistance were significantly increased after CXL. Patients requiring keratoplasty owing to corneal melting might benefit from the strengthening effect of preoperative CXL of donor tissue.
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Affiliation(s)
- Jan Lammer
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria.
| | - Maria Laggner
- Division of Thoracic Surgery, Medical University of Vienna, Vienna, Austria; Vienna Business Agency Project 2343727 "APOSEC to Clinic", Medical University of Vienna, Vienna, Austria
| | - Niklas Pircher
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Isaak Fischinger
- Department of Ophthalmology, Augentagesklinik Spreebogen Berlin, Berlin, Germany; Department of Ophthalmology, Johannes Kepler Universität, Kepler Universitätsklinikum Linz, Linz, Austria
| | - Christina Hofmann
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Gerald Schmidinger
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
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Kymionis G, Voulgari N, Samutelela E, Kontadakis G, Tabibian D. Combined Corneal Wedge Resection And Corneal Cross-Linking For Pellucid Marginal Degeneration: A First Report. Ther Clin Risk Manag 2019; 15:1319-1324. [PMID: 31814727 PMCID: PMC6858838 DOI: 10.2147/tcrm.s210606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 09/15/2019] [Indexed: 11/23/2022] Open
Abstract
Background Advanced pellucid marginal degeneration is a debilitating disease that warrants the use of surgery when the visual acuity is reduced and contact lenses are not tolerated anymore. It is traditionally managed with corneal transplantation, however alternative surgical options exist. Corneal wedge resection allows for good visual rehabilitation without the risks of tissue rejection. However topographical and refractive results are in some instance fluctuating. We present here the use of corneal cross-linking in order to stabilize the parameters on the long term. Case presentation We present here the case of a 53 years old patient with bilateral advanced pellucid marginal degeneration. As he is now intolerant to contact lenses a surgical option is offered to him. In order to avoid using donated tissue through corneal grafting we decide to perform a sectorial lamellar crescentric wedge excision of the thinner inferior part of the cornea involving the pellucid marginal degeneration and suture it. The first eye shows initial good results however after few months regression is observed. The second eye is then treated with the same surgical technique combined with cornea cross-linking. Long-term follow-up shows stabilization and absence of regression in the second eye up to eight months after the surgery. Conclusion Combining corneal cross-linking with corneal wedge resection in the case of advanced pellucid marginal degeneration patients could be a good option in order to stabilize topographical and refractive results and reduces the risk of regression.
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Affiliation(s)
- George Kymionis
- Ophthalmology Department, University of Lausanne, Jules Gonin Eye Hospital, Lausanne, Switzerland
| | - Nafsika Voulgari
- Ophthalmology Department, University of Lausanne, Jules Gonin Eye Hospital, Lausanne, Switzerland
| | - Erwin Samutelela
- Ophthalmology Department, University of Lausanne, Jules Gonin Eye Hospital, Lausanne, Switzerland
| | - George Kontadakis
- Ophthalmology Department, University of Lausanne, Jules Gonin Eye Hospital, Lausanne, Switzerland
| | - David Tabibian
- Ophthalmology Department, University of Lausanne, Jules Gonin Eye Hospital, Lausanne, Switzerland
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Lim L, Lim EWL. A Review of Corneal Collagen Cross-linking - Current Trends in Practice Applications. Open Ophthalmol J 2018; 12:181-213. [PMID: 30123383 PMCID: PMC6062907 DOI: 10.2174/1874364101812010181] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/05/2017] [Accepted: 01/22/2018] [Indexed: 01/02/2023] Open
Abstract
Objective: To review the literature on current applications of corneal Collagen Cross-Linking (CXL). Methods: A review of publications on corneal cross-linking was conducted. This included systemic reviews, randomized controlled clinical trials, cohort studies, case-controlled studies and case series. A summary of the publications is tabulated. Results: The original indication of riboflavin – Ultraviolet-A (UVA) induced corneal collagen cross-linking is to arrest the progression of keratoconus. Studies show that it is effective in arresting the progression of keratoconus and post-LASIK ectasia with the standard Dresden protocol (epithelium-off). There are also improvements in visual, keratometric and topographic measurements over time. Severe complications of cross-linking are rare. The epithelium-on techniques have less efficacy than the Dresden protocol. Accelerated protocols have variable results, with some studies reporting comparable outcomes to the Dresden protocol while other studies reporting less efficacious outcomes. Cross-linking combined with refractive procedures provide better visual outcome but long term studies are warranted. Cross-linking for the treatment of infective keratitis is a promising new treatment modality. Initial studies show that it is more effective for superficial rather than deep infections and for bacterial rather than fungal infections. Conclusions: Corneal cross-linking is a procedure with an expanding list of indications from the treatment of corneal ectasias to infective keratitis. While the standard Dresden protocol is established as the gold standard treatment for progressive keratoconus, the more recent protocols may require further refinements, investigative and long-term studies.
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Affiliation(s)
- Li Lim
- MBBS (Singapore), MMed (Ophth), FRCS(Ed), FAMS (S'pore) Senior Consultant, Corneal and External Eye Disease Service, Singapore National Eye Centre, Singapore, Singapore
| | - Elizabeth Wen Ling Lim
- Undergraduate medical student, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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Reply. Am J Ophthalmol 2018; 188:181-182. [PMID: 29454462 DOI: 10.1016/j.ajo.2018.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 11/20/2022]
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Hayes S, Meek KM, Mukherjee A. Use of Donors Predisposed by Corneal Collagen Cross-linking in Penetrating Keratoplasty for Treating Patients With Keratoconus. Am J Ophthalmol 2018; 188:181. [PMID: 29433743 DOI: 10.1016/j.ajo.2017.12.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 12/24/2017] [Indexed: 10/18/2022]
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