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Lin S, Patrawalla NY, Zhai Y, Dong P, Kishore V, Gu L. Computational and Experimental Characterization of Aligned Collagen across Varied Crosslinking Degrees. MICROMACHINES 2024; 15:851. [PMID: 39064362 PMCID: PMC11278924 DOI: 10.3390/mi15070851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/28/2024]
Abstract
Collagen-based scaffolds have been widely used in tissue engineering. The alignment of collagen fibers and the degree of crosslinking in engineering tissue scaffolds significantly affect cell activity and scaffold stability. Changes in microarchitecture and crosslinking degree also impact the mechanical properties of collagen scaffolds. A clear understanding of the effects of collagen alignment and crosslinking degrees can help properly control these critical parameters for fabricating collagen scaffolds with desired mechanical properties. In this study, combined uniaxial mechanical testing and finite element method (FEM) were used to quantify the effects of fiber alignment and crosslinking degree on the mechanical properties of collagen threads. We have fabricated electrochemically aligned collagen (ELAC) and compared it with randomly distributed collagen at varying crosslinking degrees, which depend on genipin concentrations of 0.1% or 2% for crosslinking durations of 1, 4, and 24 h. Our results indicate that aligned collagen fibers and higher crosslinking degree contribute to a larger Young's modulus. Specifically, aligned fiber structure, compared to random collagen, significantly increases Young's modulus by 112.7% at a 25% crosslinking degree (0.1% (4 h), i.e., 0.1% genipin concentration with a crosslinking duration of 4 h). Moreover, the ELAC Young's modulus increased by 90.3% as the crosslinking degree doubled by changing the genipin concentration from 0.1% to 2% with the same 4 h crosslinking duration. Furthermore, verified computational models can predict mechanical properties based on specific crosslinking degrees and fiber alignments, which facilitate the controlled fabrication of collagen threads. This combined experimental and computational approach provides a systematic understanding of the interplay among fiber alignment, crosslinking parameters, and mechanical performance of collagen scaffolds. This work will enable the precise fabrication of collagen threads for desired tissue engineering performance, potentially advancing tissue engineering applications.
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Affiliation(s)
- Shengmao Lin
- School of Civil Engineering and Architecture, Xiamen University of Technology, Xiamen 361024, China
| | - Nashaita Y. Patrawalla
- Department of Biomedical Engineering and Science, Florida Institute of Technology, Melbourne, FL 32901, USA (P.D.); (V.K.)
| | - Yingnan Zhai
- Department of Biomedical Engineering and Science, Florida Institute of Technology, Melbourne, FL 32901, USA (P.D.); (V.K.)
| | - Pengfei Dong
- Department of Biomedical Engineering and Science, Florida Institute of Technology, Melbourne, FL 32901, USA (P.D.); (V.K.)
| | - Vipuil Kishore
- Department of Biomedical Engineering and Science, Florida Institute of Technology, Melbourne, FL 32901, USA (P.D.); (V.K.)
- Department of Chemistry and Chemical Engineering, Florida Institute of Technology, Melbourne, FL 32901, USA
| | - Linxia Gu
- Department of Biomedical Engineering and Science, Florida Institute of Technology, Melbourne, FL 32901, USA (P.D.); (V.K.)
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Alghamdi A, Alghamdi EA, Alghamdi A, Abusayf MM, Ahad MA. Successful Collagen Crosslinking in a Patient With Keratoconus and Systemic Scleroderma. Cureus 2024; 16:e59431. [PMID: 38826919 PMCID: PMC11140440 DOI: 10.7759/cureus.59431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2024] [Indexed: 06/04/2024] Open
Abstract
Scleroderma is an autoimmune disease that affects connective tissue. Keratoconus (KC) is a rare ocular condition that may appear alongside scleroderma. Contact lenses are an essential visual aid for KC patients, especially in advanced cases. However, scleroderma patients may face difficulties using them due to finger-related disabilities. Corneal collagen cross-linking (CXL) is a crucial treatment used to prevent corneal thinning and visual deterioration in progressive KC. However, the potential trigger of corneal melt and delayed healing following CXL in KC patients with scleroderma is a matter of concern. We present a case of a patient with KC and scleroderma who underwent CXL without any complications.
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Affiliation(s)
- Ayman Alghamdi
- Oculoplastic Division, King Khaled Eye Specialist Hospital, Riyadh, SAU
| | | | - Abdullah Alghamdi
- Community Medicine, King Abdulaziz University Faculty of Medicine, Jeddah, SAU
| | | | - Muhammad A Ahad
- Cornea and External Disease Division, King Khaled Eye Specialist Hospital, Riyadh, SAU
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3
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Sobczak M, Jóźwik A, Kurzynowski P. An integrated model of the human cornea as a linear biaxial birefringent medium. Sci Rep 2024; 14:5077. [PMID: 38429419 PMCID: PMC10907592 DOI: 10.1038/s41598-024-55800-4] [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: 11/10/2023] [Accepted: 02/27/2024] [Indexed: 03/03/2024] Open
Abstract
A novel model of human corneal birefringence is presented. The cornea is treated as a homogeneous biaxial linear birefringent medium in which the values of the binormal axes angle and organization of the main refractive indices vary continuously from the apex to the limbus. In its central part, the angle between binormal axes is 35°, and para centrally, it smoothly increases to 83.7°. The values of the main refractive indices (nx, ny, nz) change, as well as their order, from nx < nz < ny to nz < nx < ny. The transition between these two states was described with a normal distribution (μ = 0.45, σ = 0.1). The presented model corresponds with the experimental results presented in the literature. To our knowledge, it is the first model that presents the anisotropic properties' distributions of the entire cornea. The presented model facilitates a better understanding of the corneal birefringence phenomenon directly related to its lamellar structure.
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Affiliation(s)
- Marcelina Sobczak
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
- School of Optometry, Indiana University, 800 Atwater Ave, Bloomington, IN, 47405, USA.
| | - Agnieszka Jóźwik
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - Piotr Kurzynowski
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
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Naranjo A, Manche EE. A comprehensive review on corneal crosslinking. Taiwan J Ophthalmol 2024; 14:44-49. [PMID: 38654993 PMCID: PMC11034691 DOI: 10.4103/tjo.tjo-d-23-00055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 09/01/2023] [Indexed: 04/26/2024] Open
Abstract
Corneal crosslinking (CXL) represents a paradigm shift in the management of corneal ectatic disorders. Before CXL was introduced, patients would need specialty contact lenses and possible corneal transplantation. CXL involves a biochemical reaction in which ultraviolet A light is used in conjunction with Riboflavin to form crosslinks in between corneal stromal collagen. This leads to strengthening and stabilizing of the collagen lamellae, resulting in mechanical stiffening of the cornea. Multiple protocols have been proposed including epithelium on versus off and varying light intensity and duration of treatment. All protocols appear to be safe and effective with few reported complications including infection, stromal haze, scarring, and endothelial toxicity. Overall, CXL has demonstrated to halt the progression of the disease clinically and in keratometry readings and improve the quality of life for patients. It is a minimally invasive, cost-effective procedure that can be performed in an outpatient setting with a fast recovery time and long-lasting results.
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Affiliation(s)
- Andrea Naranjo
- Department of Ophthalmology, The Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California, USA
| | - Edward E. Manche
- Department of Ophthalmology, The Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California, USA
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Ortiz-Toquero S, Fuente C, Auladell C, Arnalich-Montiel F. Influence of Keratoconus Severity on Detecting True Progression with Scheimpflug Imaging and Anterior Segment Optical Coherence Tomography. Life (Basel) 2023; 13:1474. [PMID: 37511849 PMCID: PMC10382025 DOI: 10.3390/life13071474] [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: 05/16/2023] [Revised: 06/17/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023] Open
Abstract
To determine consistent change over time in keratoconus disease, it is necessary to establish progression cut-off values based on intersession variability of the device used to monitor the cornea. The aim of this study was to analyze the accuracy of corneal parameters using Scheimpflug tomography and anterior segment optical coherence tomography in healthy and keratoconic eyes of varying severity to determine the cut-off values that indicate real progression. Three repeated measurements of each cornea of healthy (20 eyes) and keratoconic eyes (mild = 16, moderate = 25 and severe = 20) were recorded using Pentacam and Casia SS-1000 devices, which were repeated 2-3 weeks later. K1, K2, maximal anterior and posterior keratometry, and corneal thickness at the thinnest location (TCT) were collected. The accuracy was excellent with both devices; however, the Casia device presented better repeatability and reproducibility in all parameters in all groups compared to the Pentacam. The cut-off of the Pentacam and Casia in the mild stage were lower (K1 = 0.50 and 0.37 D; K2 = 0.51 and 0.37 D; Kmax-A = 1.24 and 0.65 D; Kmax-P = 0.38 and 0.17 D; TCT = 19.64 and 11.19 µm) than that of the severe stage (K1 = 1.09 and 0.88 D; K2 = 1.41 and 0.87 D; Kmax-A = 2.74 and 2.15 D; Kmax-P = 0.82 and 0.22 D; TCT = 28.68 and 14.83 µm). These results show that the greater the keratoconus severity, the greater the change that must occur for it to be considered real.
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Affiliation(s)
- Sara Ortiz-Toquero
- Department of Ophthalmology, Ramón y Cajal University Hospital, Carretera de Colmenar Viejo Km 9, 100, 28034 Madrid, Spain
- Optometry Research Group, IOBA-Eye Institute, Department of Theoretical Physics, Atomic and Optics, University of Valladolid, 47011 Valladolid, Spain
| | - Carlota Fuente
- Department of Ophthalmology, Ramón y Cajal University Hospital, Carretera de Colmenar Viejo Km 9, 100, 28034 Madrid, Spain
| | - Clara Auladell
- Department of Ophthalmology, Ramón y Cajal University Hospital, Carretera de Colmenar Viejo Km 9, 100, 28034 Madrid, Spain
| | - Francisco Arnalich-Montiel
- Department of Ophthalmology, Ramón y Cajal University Hospital, Carretera de Colmenar Viejo Km 9, 100, 28034 Madrid, Spain
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Deshmukh R, Ong ZZ, Rampat R, Alió del Barrio JL, Barua A, Ang M, Mehta JS, Said DG, Dua HS, Ambrósio R, Ting DSJ. Management of keratoconus: an updated review. Front Med (Lausanne) 2023; 10:1212314. [PMID: 37409272 PMCID: PMC10318194 DOI: 10.3389/fmed.2023.1212314] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 05/30/2023] [Indexed: 07/07/2023] Open
Abstract
Keratoconus is the most common corneal ectatic disorder. It is characterized by progressive corneal thinning with resultant irregular astigmatism and myopia. Its prevalence has been estimated at 1:375 to 1:2,000 people globally, with a considerably higher rate in the younger populations. Over the past two decades, there was a paradigm shift in the management of keratoconus. The treatment has expanded significantly from conservative management (e.g., spectacles and contact lenses wear) and penetrating keratoplasty to many other therapeutic and refractive modalities, including corneal cross-linking (with various protocols/techniques), combined CXL-keratorefractive surgeries, intracorneal ring segments, anterior lamellar keratoplasty, and more recently, Bowman's layer transplantation, stromal keratophakia, and stromal regeneration. Several recent large genome-wide association studies (GWAS) have identified important genetic mutations relevant to keratoconus, facilitating the development of potential gene therapy targeting keratoconus and halting the disease progression. In addition, attempts have been made to leverage the power of artificial intelligence-assisted algorithms in enabling earlier detection and progression prediction in keratoconus. In this review, we provide a comprehensive overview of the current and emerging treatment of keratoconus and propose a treatment algorithm for systematically guiding the management of this common clinical entity.
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Affiliation(s)
- Rashmi Deshmukh
- Department of Cornea and Refractive Surgery, LV Prasad Eye Institute, Hyderabad, India
| | - Zun Zheng Ong
- Department of Ophthalmology, Queen’s Medical Centre, Nottingham, United Kingdom
| | - Radhika Rampat
- Department of Ophthalmology, Royal Free London NHS Foundation Trust, London, United Kingdom
| | - Jorge L. Alió del Barrio
- Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
- Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain
| | - Ankur Barua
- Birmingham and Midland Eye Centre, Birmingham, United Kingdom
| | - Marcus Ang
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore, Singapore
| | - Jodhbir S. Mehta
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore, Singapore
| | - Dalia G. Said
- Department of Ophthalmology, Queen’s Medical Centre, Nottingham, United Kingdom
- Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Harminder S. Dua
- Department of Ophthalmology, Queen’s Medical Centre, Nottingham, United Kingdom
- Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Renato Ambrósio
- Department of Cornea and Refractive Surgery, Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- Department of Ophthalmology, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - Darren Shu Jeng Ting
- Birmingham and Midland Eye Centre, Birmingham, United Kingdom
- Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, United Kingdom
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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Ross AKM, Schlunck G, Böhringer D, Maier P, Eberwein P, Reinhard T, Lang SJ. Characterization of the Immediate and Delayed Biomechanical Response to UV-A Crosslinking of Human Corneas. Cornea 2023; Publish Ahead of Print:00003226-990000000-00318. [PMID: 37335854 DOI: 10.1097/ico.0000000000003336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/26/2023] [Indexed: 06/21/2023]
Abstract
PURPOSE Keratoconus leads to visual deterioration due to irregular astigmatism and corneal thinning. Riboflavin-based corneal UV-A crosslinking (CXL) induces novel intramolecular and intermolecular links resulting in corneal tissue stiffening, thereby halting disease progression. The purpose of this study was to analyze the immediate and delayed biomechanical responses of human donor corneas to CXL. METHODS CXL was performed according to the Dresden protocol to corneas not suitable for transplantation. Biomechanical properties were subsequently monitored by measuring the Young modulus using nanoindentation. The immediate tissue response was determined after 0, 1, 15, and 30 minutes of irradiation. Delayed biomechanical effects were investigated with follow-up measurements immediately and 1, 3, and 7 days after CXL. RESULTS Young's modulus indicated a linear trend in direct response to increasing irradiation times (mean values: total 61.31 kPa [SD 25.53], 0 minutes 48.82 kPa [SD 19.73], 1 minute 53.44 kPa [SD 25.95], 15 minutes 63.56 kPa [SD 20.99], and 30 minutes 76.76 kPa [SD 24.92]). The linear mixed model for the elastic response of corneal tissue was 49.82 kPa + (0.91 kPa/min × time [minutes]); P < 0.001. The follow-up measurements showed no significant delayed changes in the Young modulus (mean values: total 55,28 kPa [SD 15.95], immediately after CXL 56,83 kPa [SD 18.74], day 1 50.28 kPa [SD 14.15], day 3 57.08 kPa [SD 14.98], and day 7 56.83 kPa [SD 15.07]). CONCLUSIONS This study suggests a linear increase of corneal Young modulus as a function of CXL timing. No significant short-term delayed biomechanical changes posttreatment were observed.
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Affiliation(s)
- Andrea K M Ross
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Günther Schlunck
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Daniel Böhringer
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Philip Maier
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | | | - Thomas Reinhard
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
| | - Stefan Johann Lang
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany; and
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8
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Somohano K, Alzaga-Fernandez AG. Controversies in Corneal Collagen Crosslinking: A Review of Investigational Crosslinking Protocols and Its Off-label Application. Int Ophthalmol Clin 2022; 62:51-62. [PMID: 36170222 DOI: 10.1097/iio.0000000000000426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Dong R, Zhang Y, Yuan Y, Liu Y, Wang Y, Chen Y. A prospective randomized self-controlled study of LASIK combined with accelerated cross-linking for high myopia in Chinese: 24-month follow-up. BMC Ophthalmol 2022; 22:280. [PMID: 35751042 PMCID: PMC9233381 DOI: 10.1186/s12886-022-02491-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/09/2022] [Indexed: 11/29/2022] Open
Abstract
Background To assess the visual and refractive outcomes of femtosecond laser-assisted in situ keratomileusis (FS-LASIK) concurrent with accelerated cross-linking (LASIK Xtra) compared with conventional FS-LASIK (convLASIK) for high myopia in Chinese individuals. Methods In this prospective, randomized, fellow-eye comparison study, 25 patients with high myopia were treated randomly with LASIK Xtra in one eye and convLASIK in the other. A 24-month follow-up was conducted, and the main outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE) and corneal tomography. Results The UDVA was 0.09 ± 0.15 logMAR in the LASIK Xtra group, which was significantly worse than that in the convLASIK group 1 day postoperatively (P = .001), but the difference became nonsignificant from 1 week after surgery. The efficacy index was 0.88 ± 0.18 in the LASIK Xtra eyes and 0.99 ± 0.13 in the convLASIK eyes at 24 months (P = .028). Throughout the follow-up period, a slight myopic shift in the MRSE and keratometry values were observed in both groups without significant intergroup differences. The coefficient of determination was 0.9982 in the LASIK Xtra eyes and 0.9987 in the convLASIK eyes. The corneal density was significantly higher, and demarcation lines were visible in the first 6 months in LASIK Xtra eyes, but both signs of cross-linking gradually disappeared during follow-up. No severe complications were detected in either group. Conclusions LASIK Xtra showed comparable safety and predictability with convLASIK for high myopia in Chinese, but lower efficacy and no greater stability was observed up to 24-month follow-up.
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Affiliation(s)
- Ruilan Dong
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
| | - Yu Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
| | - Yifei Yuan
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
| | - Yan Liu
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
| | - Yuexin Wang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China
| | - Yueguo Chen
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China. .,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, Beijing, China.
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10
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Zhao J, Tian M, Li Y, Su W, Fan T. Construction of tissue-engineered human corneal endothelium for corneal endothelial regeneration using a crosslinked amniotic membrane scaffold. Acta Biomater 2022; 147:185-197. [PMID: 35358736 DOI: 10.1016/j.actbio.2022.03.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/18/2022] [Accepted: 03/23/2022] [Indexed: 11/01/2022]
Abstract
Descemet's membrane endothelial keratoplasty (DMEK) may provide fast visual rehabilitation in the therapy of corneal endothelial disorders. However, due to shortage of donated corneas, how to construct a corneal endothelial substitute with powerful functions that can be used for DMEK is still unsolved. Herein, we introduced the method of corneal crosslinking (CXL) and conjugated the components of native Descemet's membrane (DM) to improve the mechanical properties and the biocompatibility of denuded amniotic membrane (dAM), further assessed their effects on cell adhesion, proliferation, YAP translocation, and metabolic activity in human corneal endothelial (HCE) cells. Using modified crosslinked dAM (mcdAM) and non-transfected HCE cells, we constructed a tissue-engineered HCE (TE-HCE) and evaluated its functions in cat and monkey models as well. Our results showed that the mechanical properties of mcdAM were improved effectively by CXL, and the adhesion, proliferation, and YAP translocation of HCE cells were dose-dependently improved after ECM modification. The combination of 0.01 mg/mL laminin with 0.1 mg/mL fibronectin showed the highest efficacy. Then, the TE-HCE was constructed in vitro, with a high density of 3612 ± 243 cells/mm2. Results of DMEK in animal models showed that corneal transparency was maintained, accompanied with normal morphology and histological structure of the regenerated corneal endothelium. Therefore, CXL combined with DM-mimic-coating methods could effectively improve the mechanical properties of dAM and enhance the biocompatibility with HCE cells. The constructed TE-HCE had normal histological structure and functioned well in animal models via DMEK, which could be used as a promising powerful equivalent of HCE. STATEMENT OF SIGNIFICANCE: Using high-quality corneal endothelium and an appropriate endothelial keratoplasty is the most effective way for the treatment of corneal endotheliopathy. Descemet's membrane endothelial keratoplasty (DMEK) which can provide better visual acuity, lower immunological rejection rates, and improved graft survival is an ideal surgery at present. However, due to the shortage of donated corneas, it is urgent to find an equivalent substitute of corneal endothelial donor which is suitable for the DMEK surgery to solve the problem of corneal endothelial regeneration. Herein, we introduced the clinical cornea-crosslinking and Descemet's membrane-mimic-coating methods to build the modified crosslinked denuded amniotic membrane scaffold and further constructed a high-quality corneal endothelial functional substitute that can be used in DMEK surgery.
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Affiliation(s)
- Jun Zhao
- Key Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, Shandong Province, China
| | - Meng Tian
- Key Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, Shandong Province, China
| | - Yun Li
- Key Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, Shandong Province, China
| | - Wen Su
- Key Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, Shandong Province, China; Present address: Department of traditional Chinese Medicine and Immunizations, Institute of Chinese Medicine and Pharmacy, Shandong University of traditional Chinese Medicine, Jinan 250355, Shandong Province, China
| | - Tingjun Fan
- Key Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, Shandong Province, China.
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11
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Posterior corneal elevation changes and characteristic analysis 1 year after corneal collagen cross-linking for keratoconus. Int Ophthalmol 2022; 42:1457-1468. [PMID: 34989955 DOI: 10.1007/s10792-021-02135-y] [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: 07/14/2021] [Accepted: 11/12/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE To investigate the changes in posterior corneal elevations (PCEs) in the circular areas and local points after corneal collagen cross-linking (CXL) for the treatment of keratoconus. METHODS Method 1 divided the cornea into 0-2, 2-4, 4-6, and 6-8 mm regions centering on the apex. Method 2 obtained other 34 PCE values of local point that were identified on the nasal, supra-nasal, sub-nasal, superior, inferior, temporal, supra-temporal, and sub-temporal sides of the circle with diameters of 2, 4, 6, and 8 mm, and the apex and thinnest point. RESULTS Method 1 showed a forward displacement of PCE at 1 month after CXL and then a backward displacement at 3 months. In Method 2, the points on the temporal side of 2 mm and 4 mm showed the same trend. The backward displacements of PCE on the temporal side of 2 mm at 6 months and on the temporal side of 4 mm at 12 months after CXL were both statistically different than those at 1 month after CXL (P < 0.05). No significant forward displacement of PCE was found in all local points in different quadrants at 1 year after CXL. CONCLUSION The PCEs in circular areas and characteristic points of different diameters in keratoconic eyes after CXL change with time. Local point assessment of the PCE is more clinically significant. In points selected in different quadrants of the cornea, the change in temporal points was more significant after CXL.
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12
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Seyyar SA, Mete A, Kimyon S, Tıskaoğlu NS. Outcomes of customized topographic guided epithelial debridement for corneal collagen cross-linking. Int Ophthalmol 2021; 42:1273-1280. [PMID: 34727264 DOI: 10.1007/s10792-021-02114-3] [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: 04/30/2021] [Accepted: 10/21/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE To evaluate the outcomes of corneal collagen cross-linking performed with customized epithelial debridement technique in progressive keratoconic corneas. MATERIALS AND METHODS Forty eyes of 40 patients were included in the study. We performed an ophthalmologic examination and recorded the uncorrected visual acuity, best corrected visual acuity (BCVA), central corneal thickness at the thinnest point (t-CCT), flat meridian keratometry (K1), steep meridian keratometry (K2), endothelial cell density (ECC), hexagonal cells (HEX), and coefficient of variation of cell areas (CV) measured preoperatively and at the 1st, 3rd, 6th and 12th months postoperatively. RESULTS The mean UCVA and BCVA were increased (p < 0.05). The mean flattest and steepest K readings were decreased (p < 0.05). The mean t-CCT decreased in the first months after treatment and increased after 6 months. The mean t-CCT was thicker at 12 months compared to pretreatment status (p < 0.05). The mean ECC and CV were not significantly different between follow-up intervals (p > 0.05). The mean HEX was statistically increased (p > 0.05). CONCLUSIONS Corneal collagen cross-linking performed with customized epithelial debridement technique is a successful alternative method for stopping the progression of keratoconus after 12 months of treatment.
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Affiliation(s)
- Sevim Ayca Seyyar
- Kocaeli Derince Education and Research Hospital Ophthalmology Department, İbni Sina, Lojman Sk., 41900, Derince, Kocaeli, Turkey.
| | - Alper Mete
- Gaziantep University Hospital Ophthalmology Department, Gaziantep, Turkey
| | - Sabit Kimyon
- Gaziantep University Hospital Ophthalmology Department, Gaziantep, Turkey
| | - Nesime Setge Tıskaoğlu
- Ersin Arslan Education and Research Hospital Ophthalmology Department, Gaziantep, Turkey
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Development of a decellularized meniscus matrix-based nanofibrous scaffold for meniscus tissue engineering. Acta Biomater 2021; 128:175-185. [PMID: 33823327 DOI: 10.1016/j.actbio.2021.03.074] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 12/25/2022]
Abstract
The meniscus plays a critical role in knee mechanical function but is commonly injured given its central load bearing role. In the adult, meniscus repair is limited, given the low number of endogenous cells, the density of the matrix, and the limited vascularity. Menisci are fibrocartilaginous tissues composed of a micro-/nano- fibrous extracellular matrix (ECM) and a mixture of chondrocyte-like and fibroblast-like cells. Here, we developed a fibrous scaffold system that consists of bioactive components (decellularized meniscus ECM (dME) within a poly(e-caprolactone) material) fashioned into a biomimetic morphology (via electrospinning) to support and enhance meniscus cell function and matrix production. This work supports that the incorporation of dME into synthetic nanofibers increased hydrophilicity of the scaffold, leading to enhanced meniscus cell spreading, proliferation, and fibrochondrogenic gene expression. This work identifies a new biomimetic scaffold for therapeutic strategies to substitute or replace injured meniscus tissue. STATEMENT OF SIGNIFICANCE: In this study, we show that a scaffold electrospun from a combination of synthetic materials and bovine decellularized meniscus ECM provides appropriate signals and a suitable template for meniscus fibrochondrocyte spreading, proliferation, and secretion of collagen and proteoglycans. Material characterization and in vitro cell studies support that this new bioactive material is susceptible to enzymatic digestion and supports meniscus-like tissue formation.
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Nasrollahi K, Razmjoo F, Naderan M, Peyman A. Corneal cross-linking for keratoconus: Evaluation of the retina and choroid. Eur J Ophthalmol 2021; 32:1491-1495. [PMID: 34053332 DOI: 10.1177/11206721211021300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To investigate the possible structural changes of the central choroid and retina after collagen cross-linking (CXL) in patients with progressive keratoconus (KCN). METHODS Twenty-five eyes of 25 patients were included in this study. Patients underwent enhanced depth imaging optical coherence tomography (EDI-OCT) before and 1 month after CXL. The values for central macular thickness (CMT), subfoveal choroidal thickness (CHT), and choroidal volume (CHV) were evaluated. RESULTS CMT before and after CXL was 263.24 ± 16.25 μm and 263.20 ± 16.51 μm, respectively (p = 0.98). CHT was 362.08 ± 36.80 μm and 367.84 ± 33.67 μm before and after CXL, respectively (p = 0.26). CHV was 8.74 ± 0.33 mm3 and 8.68 ± 0.36 mm3 before and after CXL, respectively (p = 0.11). There was no significant difference in the corrected distance visual acuity before and after CXL (0.06 ± 0.05 and 0.05 ± 0.05 logMAR, respectively, p = 0.65). CONCLUSION Central retinal and choroidal thicknesses are not changed after corneal cross- linking.
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Affiliation(s)
- Kobra Nasrollahi
- Isfahan Eye Research Center, Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Fatemeh Razmjoo
- Isfahan Eye Research Center, Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Morteza Naderan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Peyman
- Isfahan Eye Research Center, Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran
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Aydın E, Aslan MG. The efficiency and safety of oxygen-supplemented accelerated transepithelial corneal cross-linking. Int Ophthalmol 2021; 41:2993-3005. [PMID: 33876334 DOI: 10.1007/s10792-021-01859-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 04/08/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE To investigate the impact of oxygen delivery on the clinical outcomes of accelerated transepithelial corneal cross-linking (A-TE CXL). METHODS Fifty-seven eyes of 44 progressive keratoconus (KCN) patients were randomly separated into two age-sex-matched groups. Twenty-nine eyes of 23 KCN patients that underwent oxygen-supplemented A-TE CXL formed the study group and 28 eyes of 21 patients treated with the same procedure but under room air conditions formed the control group. All patients were examined preoperatively, one, six and twelve months after the procedure. The logMAR spectacle-corrected distance visual acuity (CDVA), maximum keratometry (Kmax), mean keratometry, apical posterior keratometry, cylindrical power, minimum central corneal thickness, keratoconus vertex front and back, ocular aberrations, endothelial cell density (ECD), demarcation line depth (DLD) and proportion measures were recorded for statistical analysis. RESULTS The preoperative, 1st, 6th and 12th months mean Kmax values of the study group were 55.14 ± 3.99D, 54.85 ± 3.82D, 54.37 ± 3.84D and 54.40 ± 3.86, respectively, and 54.47 ± 3.17D, 54.52 ± 2.97D, 54.25 ± 2.95D and 54.20 ± 2.97 in the control group. The mean Kmax value was decreased significantly more in the oxygen-supplemented group after 12 months compared to the control group (p = 0.019). The mean DLD was also significantly deeper in the study group (320 ± 17 µm) compared to the control group (269 ± 19 µm). There was no significant difference between the two groups in terms of ECD alterations at any of the time intervals (p > 0.05). CONCLUSION Keratoconus progression was significantly halted in both groups 12 months after the treatment. In addition, oxygen supplementation during A-TE CXL further significantly increased clinical outcomes compared to room air conditions without any significant change in ECD measures.
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Affiliation(s)
- Emre Aydın
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Rize, Turkey
| | - Mehmet Gökhan Aslan
- Department of Ophthalmology, Recep Tayyip Erdogan University Medical Faculty, Rize, Turkey.
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16
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Vasyutin I, Butnaru D, Lyundup A, Timashev P, Vinarov A, Kuznetsov S, Atala A, Zhang Y. Frontiers in urethra regeneration: current state and future perspective. Biomed Mater 2021; 16. [PMID: 32503009 DOI: 10.1088/1748-605x/ab99d2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 06/05/2020] [Indexed: 12/13/2022]
Abstract
Despite the positive achievements attained, the treatment of male urethral strictures and hypospadiases still remains a challenge, particularly in cases of severe urethral defects. Complications and the need for additional interventions in such cases are common. Also, shortage of autologous tissue for graft harvesting and significant morbidity in the location of harvesting present problems and often lead to staged treatment. Tissue engineering provides a promising alternative to the current sources of grafts for urethroplasty. Since the first experiments in urethral substitution with tissue engineered grafts, this topic in regenerative medicine has grown remarkably, as many different types of tissue-engineered grafts and approaches in graft design have been suggested and testedin vivo. However, there have been only a few clinical trials of tissue-engineered grafts in urethral substitution, involving hardly more than a hundred patients overall. This indicates that the topic is still in its inception, and the search for the best graft design is continuing. The current review focuses on the state of the art in urethral regeneration with tissue engineering technology. It gives a comprehensive overview of the components of the tissue-engineered graft and an overview of the steps in graft development. Different cell sources, types of scaffolds, assembling approaches, options for vascularization enhancement and preclinical models are considered.
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Affiliation(s)
- Igor Vasyutin
- Sechenov University, 8-2 Trubetskaya str., Moscow 119991, Russia
| | - Denis Butnaru
- Sechenov University, 8-2 Trubetskaya str., Moscow 119991, Russia
| | - Alexey Lyundup
- Sechenov University, 8-2 Trubetskaya str., Moscow 119991, Russia
| | - Peter Timashev
- Sechenov University, 8-2 Trubetskaya str., Moscow 119991, Russia
| | - Andrey Vinarov
- Sechenov University, 8-2 Trubetskaya str., Moscow 119991, Russia
| | - Sergey Kuznetsov
- Sechenov University, 8-2 Trubetskaya str., Moscow 119991, Russia
| | - Anthony Atala
- Wake Forest Institute for Regenerative Medicine, 391 Technology Way NE, Winston-Salem, NC 27101, United States of America
| | - Yuanyuan Zhang
- Sechenov University, 8-2 Trubetskaya str., Moscow 119991, Russia.,Wake Forest Institute for Regenerative Medicine, 391 Technology Way NE, Winston-Salem, NC 27101, United States of America
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17
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Conde Penedo A, Díaz Tomé V, Fernández Ferreiro A, González Barcia M, Otero Espinar FJ. Enhancement in corneal permeability of riboflavin using cyclodextrin derivates complexes as a previous step to transepithelial cross-linking. Eur J Pharm Biopharm 2021; 162:12-22. [PMID: 33667681 DOI: 10.1016/j.ejpb.2021.02.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/15/2021] [Accepted: 02/23/2021] [Indexed: 01/14/2023]
Abstract
Corneal cross-linking has been described as an effective treatment to slow the progression of keratoconus. The standard protocol entails corneal epithelial removal to allow the diffusion of riboflavin into the stroma. Although, de-epithelization can generate risks or complications that transepithelial cross-linking tries to solve or avoid. Different formulations were developed after verifying that hydroxypropyl-β-cyclodextrin (HPβCD) and sulfobuthylether-β-cyclodextrin (SBEβCD) in a 20% concentration, increased the solubility of practically insoluble in water drugs such as riboflavin from 0.12 mg/mL to 0.35 mg/mL and 0.29 mg/mL respectively. These values were higher when chitosan and arginine were added to the formulation, showing solubility of 0.78 mg/mL when HPβCD concentration was not modified. Ex vivo corneal permeability was measured after having kept in contact bovine corneas with intact epithelium for 5 h with the 0.1 mg/mL riboflavin solution, the formulations developed and a reproduced nanoemulsion from another work. Riboflavin's permeability was increased when cyclodextrins, chitosan, and arginine were part of the formulations, compared to the control drug solution. The best permeability coefficient was reached when riboflavin was combined with 40% (w/v) HPβCD, 0.5% (w/w) arginine, and 0.5% (w/w) chitosan. After having carried out toxicity studies as bovine corneal opacity and permeability (BCOP) and Heńs Egg Test - Chorioallantoic Membrane Test (HET-CAM) it was verified that both, the active ingredients and the excipients of the different formulations were not harmful without generating irritation, loss of transparency or corneal permeability alterations. The results show the great potential of the ocular developed solution for their use in transepithelial cross-linking for keratoconus treatment.
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Affiliation(s)
- Andrea Conde Penedo
- Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain; Paraquasil Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Victoria Díaz Tomé
- Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain; Clinical Pharmacology Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Anxo Fernández Ferreiro
- Pharmacy Department, University Clinical Hospital Santiago de Compostela, Santiago de Compostela, Spain; Clinical Pharmacology Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.
| | - Miguel González Barcia
- Pharmacy Department, University Clinical Hospital Santiago de Compostela, Santiago de Compostela, Spain; Clinical Pharmacology Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.
| | - Francisco J Otero Espinar
- Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain; Paraquasil Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.
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Li M, Wei R, Yang W, Shang J, Fu D, Xia F, Choi J, Zhou X. Femtosecond Laser-Assisted Allogenic Lenticule Implantation for Corneal Ectasia After LASIK: A 3-Year In Vivo Confocal Microscopic Investigation. J Refract Surg 2020; 36:714-722. [PMID: 33170278 DOI: 10.3928/1081597x-20200826-02] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/13/2020] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate morphological changes in the cornea and the implanted lenticule in patients with corneal ectasia after laser in situ keratomileusis (LASIK) and implantation using a lenticule from small incision lenticule extraction (SMILE). METHODS Eight eyes of 8 patients with ectasia after LASIK from 2015 to 2018 at the Eye and ENT Hospital of Fudan Unversity were analyzed. For recipient eyes, lenticules were transferred with a mean cryopreserved time of 20 ± 21 days extracted from SMILE donors to the exposed stromal bed after lifting the flaps and the flap was repositioned. Uncorrected and corrected distance visual acuity, manifest refraction, and corneal topography were performed. Patients were followed up for 3 years. Changes in lenticules and recipient corneas were analyzed using in vivo confocal microscopy. RESULTS Activated keratocytes in the anterior and posterior stroma were observed near the lenticule at the first 6 months. Elongated, deformed keratocyte nuclei were found in the implanted lenticules in postoperative year 1. The anterior and posterior interfaces showed an absence or decrease of keratocytes and the presence of small particles of varying brightness. Nerve fibers in the implanted lenticules were detected in one case. No obvious difference was detected between cryopreserved and fresh lenticules. CONCLUSIONS The preliminary findings suggest that recipient keratocytes repopulate the lenticules and the keratocytes in lenticules gradually return to their normal morphology. [J Refract Surg. 2020;36(11):714-722.].
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Comparison of Visual and Tomographic Outcomes of Epithelium-On and Epithelium-Off Accelerated Corneal Crosslinking: A Longitudinal Study. Cornea 2020; 40:643-647. [PMID: 33079917 DOI: 10.1097/ico.0000000000002567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/03/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare the visual and tomographic outcomes of epithelium-on and epithelium-off corneal collagen crosslinking (CXL) in an accelerated protocol in eyes with progressive keratoconus. METHODS Sixty-one patients with progressive keratoconus (female patients, n = 30; male patients, n = 31) aged 17 and 48 years (mean age: 25.8 ± 6.2 yrs) were included in this study. Patients underwent either epithelium-off (n = 27) or epithelium-on (n = 34) CXL using an accelerated protocol. Patients with at least 12 months of follow-up were included in the study. Visual and tomographic data from 3, 6, and 12 months after surgery were analyzed. RESULTS There were no differences between the visual and tomographic characteristics of the epithelium-on and epithelium-off groups at baseline (P > 0.05). No significant changes in uncorrected and best spectacles-corrected visual acuity were found at any stage during the first 12 months within either group or between the groups (all P > 0.05). There were no changes in thickness and keratometric parameters at any stage during the first 12 months within either group, or between groups (P > 0.05) except for a transient significant thinning of the central cornea in all groups in the first 3 months which recovered by 6 months. There was no significant difference between groups regarding the number of eyes with progression in the 12 months after treatment (P > 0.05). CONCLUSIONS Epithelium-on and epithelium-off CXL in an accelerated protocol provide comparable visual and tomographic outcomes after 1 year in eyes with progressive keratoconus.
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20
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Safety, Efficacy, and Predictive Factors of Conventional Epithelium-Off Corneal Crosslinking in the Treatment of Progressive Keratoconus. J Ophthalmol 2020; 2020:7487186. [PMID: 32566268 PMCID: PMC7281816 DOI: 10.1155/2020/7487186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/11/2020] [Accepted: 04/21/2020] [Indexed: 11/18/2022] Open
Abstract
Purpose To report predictive factors of outcome of conventional epithelium-off corneal crosslinking (CXL) in the treatment of progressive keratoconus. Methods This is a monocentric observational retrospective study conducted at Eye and Ear International Hospital, Lebanon. All patients with progressive keratoconus who underwent CXL between January 2008 and January 2016, with minimal 3-years follow-up were included. Primary treatment outcomes were maximum keratometry (K max), best-corrected distance visual acuity (CDVA), and failure. Failure was defined as an increase of 1.00 diopters (D) or more in K max and/or an increase of 0.1 logMAR or more in CDVA and conversion to corneal transplantation. Statistical analysis was done to identify predictors of treatment success. Univariate and multivariate analyses were performed to determine the correlations between baseline parameters and outcomes, and an equation for predicting K max and CDVA was created. Results 156 eyes of 102 patients were enrolled. The mean age was 23.85 ± 6.52 years. Failure occurred in 31 eyes (19.87%). Gender and thinnest pachymetry did not have any impact on postoperative outcomes. Concerning the CDVA outcome, multivariate analysis showed that a better preoperative CDVA was associated with higher improvement in CDVA, and higher baseline K max and higher posterior mean K were associated with a worse outcome CDVA. Regarding postoperative K max, a higher baseline K max, a worse baseline CDVA, and a younger age were associated with less flattening postoperatively. Conclusion CXL is a safe and effective method in treating progressive keratoconus. However, the clinical benefits can differ among patients, and in our series, a nonnegligible number of cases show a continued progression of their ectasia. Further studies to identify predictors of postoperative progression prior to the procedure could help sort out good responders to treatment.
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21
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Corneal Cross-linking: Epi-On vs. Epi-Off Current Protocols, Pros, and Cons. CURRENT OPHTHALMOLOGY REPORTS 2020. [DOI: 10.1007/s40135-020-00241-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Arrizabalaga JH, Nollert MU. Riboflavin-UVA crosslinking of amniotic membranes and its influence on the culture of adipose-derived stem cells. J Mech Behav Biomed Mater 2020; 106:103729. [PMID: 32250944 DOI: 10.1016/j.jmbbm.2020.103729] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/31/2020] [Accepted: 02/26/2020] [Indexed: 02/04/2023]
Abstract
The human amniotic membrane (hAM) is a collagen-based extracellular matrix whose applications are restricted by its moderate mechanical properties and rapid biodegradation. In this work, we investigate the use of riboflavin, a water-soluble vitamin, to crosslink and strengthen the human amniotic membrane under UVA light. The effect of riboflavin-UVA crosslinking on hAM properties were determined via infrared spectroscopy, uniaxial tensile testing, proteolytic degradation, permeability testing, SEM, and quantification of free (un-crosslinked) amine groups. Samples crosslinked with glutaraldehyde, a common and effective yet cytotoxic crosslinking agent, were used as controls. Improved hAM mechanical properties must not come at the expense of reduced cellular proliferation and induction capabilities. In this study, we assessed the viability, proliferation, immunophenotype, and multilineage differentiation ability of human adipose-derived stem cells seeded on riboflavin-UVA crosslinked membranes. Overall, hAM crosslinked with riboflavin-UVA benefited from a stable three-fold increase in mechanical properties (comparable to the increase seen with glutaraldehyde crosslinked membranes) and improved biodegradation, all while retaining their biocompatibility and abilities to support the cultivation and differentiation of adipose-derived stem cells. Together, these results suggest that riboflavin-UVA crosslinking is an effective strategy to enhance the hAM for tissue engineering and regenerative medicine applications establishing it as an attractive and tuneable biomaterial.
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Affiliation(s)
- Julien H Arrizabalaga
- Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, United States
| | - Matthias U Nollert
- Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, OK, United States; School of Chemical, Biological & Materials Engineering, University of Oklahoma, Norman, OK, United States.
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23
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Uchida K, Himori N, Hashimoto K, Shiga Y, Tsuda S, Omodaka K, Nakazawa T. The association between oxidative stress and corneal hysteresis in patients with glaucoma. Sci Rep 2020; 10:545. [PMID: 31953470 PMCID: PMC6969044 DOI: 10.1038/s41598-020-57520-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/11/2019] [Indexed: 12/31/2022] Open
Abstract
Systemic antioxidative status has been implicated in glaucoma pathogenesis. Additionally, corneal hysteresis (CH) may contribute to glaucoma progression. Here, we evaluated the relationship between biological antioxidant potential (BAP) and CH. This study included 103 patients with open-angle glaucoma (OAG). We used a free radical analyzer to measure BAP, and an ocular response analyzer to measure CH and corneal resistance factor (CRF). We evaluated the relationship between systemic oxidative stress and other clinical parameters with Spearman's rank correlation test and a multi-regression analysis. BAP was not correlated to either CH or CRF in the male or female OAG patients. BAP was correlated to both CH and CRF in the female OAG patients older than 57 years (r = 0.51, P = 0.003; r = 0.49, P = 0.004), but uncorrelated in the female OAG patients younger than 57 years. Multiple regression analysis revealed that BAP independently contributed to CH (P = 0.025) and CRF (P = 0.015) in the older female OAG patients. Systemic oxidative stress may significantly affect the viscoelasticity of the cornea in older female OAG patients. Future studies are needed to confirm that low systemic antioxidative status and low corneal hysteresis contribute to glaucoma pathogenesis.
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Affiliation(s)
- Keiko Uchida
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Noriko Himori
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuki Hashimoto
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yukihiro Shiga
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Satoru Tsuda
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuko Omodaka
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan.
- Collaborative Program for Ophthalmic Drug Discovery, Tohoku University Graduate School of Medicine, Sendai, Japan.
- Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Sendai, Japan.
- Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan.
- Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Al-Mohaimeed MM. Combined corneal CXL and photorefractive keratectomy for treatment of keratoconus: a review. Int J Ophthalmol 2019; 12:1929-1938. [PMID: 31850179 DOI: 10.18240/ijo.2019.12.16] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/29/2019] [Indexed: 12/15/2022] Open
Abstract
Keratoconus and iatrogenic keratectasia are the corneal ectatic disorders occurring due to biomechanical weakening of the cornea resulting in distorted images, myopia, and irregular astigmatism. Corneal collagen cross-linking (CXL) is performed to arrest keratoconus successfully. The main aim of this review is to discuss the safety and efficacy of the adjuvant therapies, such as the combination of CXL and photorefractive keratectomy (PRK) for the treatment of corneal ectatic disorders. A comprehensive literature search was performed using PubMed, MEDLINE, and Scopus using keywords 'collagen' 'keratoconus', 'keratectasia', 'collagen cross-linking', and 'photorefractive keratectomy'. Search results were restricted to clinical studies published in English. Corneal CXL effectively arrests the progression of keratoconus by enhancing corneal rigidity. However, functional vision is not improved by cross-linking. Combining CXL to refractive surgeries such as topography-guided PRK or transepithelial PRK is found to be a safe and effective method in providing corneal stability as well as significantly improving functional visual acuity with few minor complications. This combined technique also prevents regression of keratoconus and reduce the risk of keratectasia. CXL combined with PRK is a promising therapeutic approach in ophthalmology that can be successfully used to treat progressive keratoconus and other corneal ectatic disorders and to enhance visual acuity.
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Affiliation(s)
- Mansour M Al-Mohaimeed
- Department of Ophthalmology, College of Medicine, Qassim University, Qassim, Buraidah 51452, Kingdom of Saudi Arabia
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25
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DeParis SW, Zhu AY, Majumdar S, Tian J, Elisseeff J, Jun AS, Mahoney NR. Effects of collagen crosslinking on porcine and human tarsal plate. BMC Ophthalmol 2019; 19:255. [PMID: 31842794 PMCID: PMC6915903 DOI: 10.1186/s12886-019-1254-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/21/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Floppy eyelid syndrome is a disorder in which the tarsal plate is easily distensible and is currently treated with conservative or surgical measures. Human tarsal plate contains type I collagen, which is crosslinked in corneal tissue as a treatment for keratoconus. We hypothesized that collagen crosslinking would similarly stiffen tarsal plate tissue and investigated this in porcine and human tarsal plate specimens. METHODS Riboflavin-sensitized porcine and human tarsus samples were irradiated with ultraviolet-A light. Porcine experiments were analyzed with gross photographs, anterior segment optical computed tomography (AS-OCT) imaging, and tensile testing. A prospective study of human tarsus was performed on samples from patients undergoing wedge resection for floppy eyelid syndrome and was analyzed with AS-OCT and tensile testing. RESULTS 73 porcine adnexa and 9 patients (16 eyelids) who underwent wedge excision were included in the study. Grossly, greater stiffness was observed in crosslinked porcine tissue. AS-OCT imaging in porcine tissue showed a distinct hyperreflective band in crosslinked specimens whose area and intensity increased with longer treatment time (P = 0.003); this band was also visible in crosslinked human specimens. Tensile testing was performed, but results were not statistically significant. CONCLUSIONS AS-OCT imaging, which has not been previously described for tarsal plate, showed a characteristic change in crosslinked porcine and human specimens. Tissue stiffness was increased grossly, but changes in tensile properties were not statistically significant. Further study is warranted to determine relevance as a potential treatment for floppy eyelid syndrome.
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Affiliation(s)
- Sarah W DeParis
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD, 21287, USA
| | - Angela Y Zhu
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD, 21287, USA
| | - Shoumyo Majumdar
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD, 21287, USA
| | - Jing Tian
- Department of Biostatistics, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Jennifer Elisseeff
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD, 21287, USA.,Department of Biomedical Engineering, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Albert S Jun
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD, 21287, USA
| | - Nicholas R Mahoney
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD, 21287, USA.
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Omar IAN, Zein HA. Accelerated Epithelium-Off Corneal Collagen Cross-Linking For Keratoconus: 12-Month Results. Clin Ophthalmol 2019; 13:2385-2394. [PMID: 31824132 PMCID: PMC6900281 DOI: 10.2147/opth.s232118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 10/22/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose The main aim of the study was to report visual, refractive, topographic, and aberrometric results of accelerated CXL in patients with keratoconus who were followed for 12 months and to highlight the important parameters that can be used in follow-up. Settings It was a prospective interventional non-randomized case series study, in which 40 keratoconus eyes of 40 patients were studied in the period between April 2016 and July 2018. Methods All eyes were examined preoperatively and post-accelerated CXL to evaluate visual acuity, refractive state, keratometric values, keratoconus indices, and corneal higher order aberrations (HOAs). Results The mean age of the studied patients was 28.4 ± 8.6 years (18-37years). One year after cross-linking, 11.6% of the eyes gained two lines of the UCVA, 26.4% of the eyes gained one line, 49.8% showed no change, 7.1% lost one line, and 5.1% lost two lines. Postoperative BCVA showed 13.7% of the eyes gained at least two lines, 32.5% gained one line, 49.9% had no change, and 3.9% lost one line. The keratometric values changed significantly after CXL; K1 decreased by a mean of 0.41D, K2 by 0.62D while Kmax by 1.57 D. The significant changes in keratoconus indices were in index of vertical asymmetry (IVA), index of surface variance (ISV), and keratoconus index (KI). Vertical coma, spherical aberrations, and trefoil decreased significantly at 12 months compared to baseline values (p = 0.04, 0.017, 0.025, respectively). Conclusion Keratoconus indices especially ISV, IVA, and KI along with HOAsparticularly vertical coma, spherical aberrations, and trefoil can add value beside keratometric readings in the follow-up of eyes treated with accelerated CXL.
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Affiliation(s)
| | - Hosny Ahmed Zein
- Ophthalmology Department, Faculty of Medicine, Minia University, El-Minya, Egypt
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Perez VL, Wirostko B, Korenfeld M, From S, Raizman M. Ophthalmic Drug Delivery Using Iontophoresis: Recent Clinical Applications. J Ocul Pharmacol Ther 2019; 36:75-87. [PMID: 31755807 DOI: 10.1089/jop.2019.0034] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background: Iontophoresis is a noninvasive delivery system designed to overcome barriers to ocular penetration of topical ophthalmic medications by employing a low-amplitude electrical current to promote the migration of a charged drug substance across biological membranes. Trans-scleral iontophoresis of dexamethasone phosphate has demonstrated dramatically increased intraocular concentrations of dexamethasone in rabbit ocular tissues compared with topical instillation, including 50- to 100-fold greater aqueous humor concentrations. Methods: This article reviews available data on recent clinical applications of iontophoretic ophthalmic drug delivery. Results: The EyeGate II delivery system (EGDS) is a trans-scleral iontophoresis system that has been used in conjunction with EGP-437, a proprietary-charged formulation of dexamethasone phosphate for iontophoretic delivery. In patients with noninfectious anterior uveitis, EGP-437, delivered through 2 iontophoretic treatments using the EGDS, demonstrated similar efficacy to topical prednisolone acetate 1% eye drops instilled 8 times daily over 28 days, suggesting the potential to decrease or eliminate the need for daily dosing of topical steroids in this patient population. Other applications for EGP-437 delivered through the EGDS that have been explored in clinical trials include treatment of dry eye, postsurgical inflammation and pain, and scleritis. In addition, transcorneal iontophoresis has been used outside of the United States to enhance riboflavin penetration in patients undergoing corneal cross-linking as therapy for progressive keratoconus. Conclusions: The reviewed studies demonstrate the feasibility of using iontophoresis to enhance drug delivery to ocular tissues and support the potential of this noninvasive technique across a range of ophthalmic indications.
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Affiliation(s)
| | - Barbara Wirostko
- EyeGate Pharmaceuticals, Inc., Waltham, Massachusetts.,Department of Ophthalmology Moran Eye Center, and Bio Medical Engineering, University of Utah, Salt Lake City, Utah
| | | | - Stephen From
- EyeGate Pharmaceuticals, Inc., Waltham, Massachusetts
| | - Michael Raizman
- Ophthalmic Consultants of Boston, Boston, Massachusetts.,New England Eye Center, Tufts University School of Medicine, Boston Massachusetts
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Corneal crosslinking: Current protocols and clinical approach. J Cataract Refract Surg 2019; 45:1670-1679. [DOI: 10.1016/j.jcrs.2019.06.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 05/19/2019] [Accepted: 06/21/2019] [Indexed: 12/18/2022]
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Piyacomn Y, Kasetsuwan N, Puangsricharern V, Reinprayoon U, Satitpitakul V, Chantaren P. Topometric Indices And Corneal Densitometry Change After Corneal Refractive Surgery Combined With Simultaneous Collagen Crosslinking. Clin Ophthalmol 2019; 13:1927-1933. [PMID: 31579231 PMCID: PMC6773968 DOI: 10.2147/opth.s225909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 09/05/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose To show the alteration of tomography, topometric indices and corneal densitometry after corneal refractive surgery combined with collagen crosslinking. Patients and methods All medical records of patients undergoing corneal refractive surgery with simultaneous collagen crosslinking during April 2015 and August 2018 were retrospectively reviewed. Corneal tomography, higher-order aberrations (HOA), topographic indices and corneal densitometry were evaluated. All the data at 1 month, 3 months and 6 months were compared to baseline value. All complications were noted. P value less than 0.05 was considered statistically significant. Results Medical records of fourteen patients (twenty-five eyes) were reviewed. HOA increased at all time points (p < 0.05). Keratoconus index and central keratoconus index decreased, whereas index of surface variance, index of vertical asymmetry, index of height decentration and the minimum of radius of curvature increased at all time points (p < 0.05). Index of height asymmetry increased at 3 and 6 months (p < 0.05). Corneal densitometry at anterior layer of 0–10 mm zone and center layer of 0–6 mm zone increased at 1 and 3 months (p < 0.05). At 6 months, the densitometry at 0–6 mm zone returned to baseline level. However, at 6 months, at anterior and center layer of 6–10 mm zone, the densitometry values were still more than preoperative values (p < 0.05). There was one case of bacterial keratitis. Conclusion After the corneal refractive surgery combined with collagen crosslinking, the HOA and corneal densitometry increased. Topographic indices showed conflicting results.
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Affiliation(s)
- Yonrawee Piyacomn
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Ngamjit Kasetsuwan
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Vilavun Puangsricharern
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Usanee Reinprayoon
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Vannarut Satitpitakul
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Patchima Chantaren
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
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Histological Corneal Alterations in Keratoconus After Crosslinking—Expansion of Findings. Cornea 2019; 39:333-341. [DOI: 10.1097/ico.0000000000002144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Belviranli S, Oltulu R. Efficacy of pulsed-light accelerated crosslinking in the treatment of progressive keratoconus: Two-year results. Eur J Ophthalmol 2019; 30:1256-1260. [PMID: 31505958 DOI: 10.1177/1120672119872375] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE The aim of this study was to evaluate the 2-year results of epithelium-off pulsed-light accelerated corneal collagen crosslinking treatment in progressive keratoconus using 30 mW/cm2 ultraviolet A light for 6 min with a total dose of 5.4 J/cm2. METHODS A total of 30 eyes of 22 patients with documented progressive keratoconus and treated with epithelium-off pulsed-light accelerated corneal collagen crosslinking using the KXL® crosslinking device (Avedro Inc, Waltham, MA, USA) were included in this retrospective study. Corneal tomographic measurements and best spectacle-corrected visual acuity were compared using analysis of variance with repeated measurements between the baseline visit (before the corneal collagen crosslinking treatment), and the sixth month, first, and second year visits. RESULTS Flat keratometry (K1), steep keratometry (K2), and mean keratometry (Km) decreased significantly at sixth month, first, and second years (p < 0.001, p = 0.001, and p < 0.001, respectively). Maximum keratometry (Kmax) decreased from 55.40 ± 4.90 D at baseline to 54.82 ± 4.68 D, 54.80 ± 5.12 D, and 54.65 ± 5.36 D at sixth month, first year, and second year, respectively (p = 0.007). The best spectacle-corrected visual acuity improved from 0.34 ± 0.24 logMAR at baseline to 0.25 ± 0.16 logMAR, 0.22 ± 0.15 logMAR, and 0.17 ± 0.13 logMAR at sixth month, first year, and second year, respectively (p < 0.001). At the second year visit, best spectacle-corrected visual acuity remained stable (no lines lost) with respect to the baseline in 8 eyes and increased 1 or more lines in 22 eyes. CONCLUSION Pulsed-light accelerated corneal collagen crosslinking using 30 mW/cm2 ultraviolet A light for 6 min with a total dose of 5.4 J/cm2 is an effective treatment modality in cases with progressive keratoconus-it stops progression at 2 years also regresses some of the cases.
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Affiliation(s)
- Selman Belviranli
- Department of Ophthalmology, Meram School of Medicine, Necmettin Erbakan University, Konya, Turkey
| | - Refik Oltulu
- Department of Ophthalmology, Meram School of Medicine, Necmettin Erbakan University, Konya, Turkey
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Transepithelial Phototherapeutic Keratectomy Followed by Corneal Collagen Crosslinking for the Treatment of Pellucid Marginal Degeneration: Long-term Results. Cornea 2019; 38:980-985. [PMID: 31107284 DOI: 10.1097/ico.0000000000002003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE To evaluate visual, refractive, topographic, and aberrometric outcomes of transepithelial phototherapeutic keratectomy (PTK) + corneal collagen crosslinking in the treatment of pellucid marginal degeneration. METHODS This retrospective study includes 20 eyes of 15 patients with pellucid marginal degeneration treated with transepithelial PTK + accelerated corneal collagen crosslinking. Visual acuity, refraction, topographic keratometry, pachymetry, and aberrations were recorded pretreatment and 6, 12, 24, and 36 months after treatment. RESULTS Stabilization in visual acuity was observed throughout the 36 months of follow-up (P > 0.05). The cylindrical value was significantly lower (P < 0.05) during the follow-up compared with the baseline (4.97 ± 2.00, 3.86 ± 2.01, 3.92 ± 2.27, 2.87 ± 1.70, and 3.28 ± 3.12 D at the baseline and postoperative 6th, 12th, 24th, and 36th month, respectively). Spherical equivalent was significantly lower at the 24th (P = 0.02) and 36th month (P = 0.01) follow-up intervals. A significant decrease (P < 0.05) in average keratometry readings was observed in all follow-up points (47.12 ± 4.66, 46.65 ± 4.38, 46.57 ± 4.57, 46.46 ± 4.81, and 46.27 ± 4.46 D, respectively). The maximum keratometry value remained stable (P > 0.05) in all visits (64.30 ± 10.70, 63.49 ± 10.05, 62.97 ± 9.50, 63.33 ± 10.06, and 62.27 ± 10.36 D, respectively). The Baiocchi Calossi Versaci index was significantly lower (P < 0.05) at all follow-up points compared with the baseline (3.21 ± 1.93, 2.99 ± 1.96, 2.96 ± 1.93, 2.82 ± 1.95, and 2.86 ± 1.99 μm, respectively). Central and minimum corneal thicknesses were significantly lower (P ≤ 0.01) compared with the baseline throughout the follow-up. Higher order aberration, trefoil, coma, and spherical aberration values remained stable during the follow-up compared with the baseline (P > 0.05). CONCLUSIONS The combination of transepithelial PTK with accelerated corneal collagen crosslinking seems to be an effective treatment in patients with pellucid marginal degeneration in the long-term.
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Abbondanza M, Abbondanza G, De Felice V, Wong ZSY. Long-term Results of Mini Asymmetric Radial Keratotomy and Corneal Cross-linking for the Treatment of Keratoconus. KOREAN JOURNAL OF OPHTHALMOLOGY 2019; 33:189-195. [PMID: 30977329 PMCID: PMC6462470 DOI: 10.3341/kjo.2018.0028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/28/2018] [Indexed: 11/23/2022] Open
Abstract
Purpose To investigate the long-term results (at least 5 years of follow-up) of the mini asymmetric radial keratotomy (MARK) and corneal cross-linking (CXL) combined intervention, also known as the ‘Rome protocol,’ for patients with progressive stage I and II keratoconus and contact lens intolerance. Methods This was a retrospective observational case series. Fifteen eyes of 12 patients were evaluated, with a mean follow-up of 6.9 years. To assess the efficacy and stability of the MARK + CXL combined protocol, best spectacle-corrected visual acuity, mean pachymetry, and mean keratometry were recorded preoperatively and at least 1, 3, and 5 years postoperatively. Statistical analysis was performed using the R platform and involved the Wilcoxon signed-rank and Kruskal-Wallis non-parametric tests. Results Best spectacle-corrected visual acuity improved for all patients, from 0.46 ± 0.69 logarithm of the minimum angle of resolution (20 / 60) to 0.15 ± 0.69 logarithm of the minimum angle of resolution (20 / 30, p = 0.0006), while mean pachymetry increased in 93% of patients, from 442.80 ± 61.02 to 464.50 ± 62.72 µm (p = 0.003). Lastly, mean keratometry improved in 87% of patients after 6.9 years of observation from 48.82 ± 5.00 to 43.25 ± 3.58 diopters (p = 0.008). No intraoperative or postoperative complications were observed. Conclusions The MARK + CXL combined protocol was effective in treating keratoconus by halting corneal thinning and bulging. In addition, this procedure significantly improved visual acuity based on long-term follow-up data. Analysis of data from a larger cohort of patients would be useful to support these findings.
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Affiliation(s)
| | - Gabriele Abbondanza
- Abbondanza Eye Centers, Rome and Milan, Italy.,Centre for International Security Studies, The University of Sydney, Sydney, Australia
| | | | - Zoie Shui Yee Wong
- Graduate School of Public Health, St. Luke's International University, Tokyo, Japan
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Madeira C, Vasques A, Beato J, Godinho G, Torrão L, Falcão M, Falcão-Reis F, Pinheiro-Costa J. Transepithelial accelerated versus conventional corneal collagen crosslinking in patients with keratoconus: a comparative study. Clin Ophthalmol 2019; 13:445-452. [PMID: 30880905 PMCID: PMC6402612 DOI: 10.2147/opth.s189183] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Purpose To systematically compare the efficacy of transepithelial accelerated corneal collagen crosslinking (TE-ACXL) with conventional corneal collagen crosslinking (C-CXL) in patients with progressive keratoconus. Methods Eyes of patients with progressive keratoconus who were treated with C-CXL (3 mW/cm2 for 30 minutes) were compared with those who underwent TE-ACXL (6 mW/cm2 for 15 minutes). Best-corrected visual acuity (BCVA), keratometry values, corneal thickness, and topometric indexes were compared before CXL, and at 2 months, 6 months, and 12 months postoperatively. Results The study enrolled 26 eyes of which 16 had TE-ACXL and 10 had C-CXL. Both groups were comparable at baseline and 12 months in terms of BCVA (P=0.16 and P=0.57), Kmax (maximum keratometry) (P=0.31 and P=0.73), pachymetry (P=0.75 and P=0.37), index of surface variance (ISV) (P=0.45 and P=0.86), index of vertical asymmetry (IVA) (P=0.26 and P=0.61), and index of height decentration (IHD) (P=0.27 and P=0.86, respectively). We did not observe significant differences between preoperative and 12-month postoperative readings in within-group analysis: ΔKmax (TE-ACXL, −2.13±5.41, P=0.25 vs C-CXL, 0.78±1.65, P=0.17), Δpachymetry (TE-ACXL, 4.10±14.83, P=0.41 vs C-CXL, −8.90±22.09, P=0.24), ΔISV (TE-ACXL, −8.50±21.26, P=0.24 vs C-CXL, 3.80±12.43, P=0.36), ΔIVA (TE-ACXL, −0.12±0.31, P=0.26 vs C-CXL, 0.03±0.18, P=0.61), and ΔIHD (TE-ACXL, −0.03±0.07, P=0.18 vs C-CXL, −0.01±0.03, P=0.88). Conclusion Both TE-ACXL and C-CXL were similarly effective. Further follow-up is required to determine whether these techniques are comparable in the long-term.
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Affiliation(s)
- Carolina Madeira
- Department of Ophthalmology, Centro Hospitalar de São João, Porto, Portugal,
| | - Ana Vasques
- Faculty of Medicine, University of Porto, Porto, Portugal
| | - João Beato
- Department of Ophthalmology, Centro Hospitalar de São João, Porto, Portugal,
| | - Gonçalo Godinho
- Department of Ophthalmology, Centro Hospitalar de São João, Porto, Portugal,
| | - Luís Torrão
- Department of Ophthalmology, Centro Hospitalar de São João, Porto, Portugal,
| | - Manuel Falcão
- Department of Ophthalmology, Centro Hospitalar de São João, Porto, Portugal, .,Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Fernando Falcão-Reis
- Department of Ophthalmology, Centro Hospitalar de São João, Porto, Portugal, .,Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal
| | - João Pinheiro-Costa
- Department of Ophthalmology, Centro Hospitalar de São João, Porto, Portugal, .,Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
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Cagini C, Di Lascio G, Messina M, Riccitelli F, Dua HS. Correlation of central and peripheral keratometric parameters after corneal collagen cross-linking in keratoconus patients. Int Ophthalmol 2018; 39:2041-2048. [PMID: 30421316 DOI: 10.1007/s10792-018-1041-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 11/07/2018] [Indexed: 02/06/2023]
Abstract
PURPOSE To evaluate the difference in the central and peripheral keratometric parameters in patients with keratoconus after corneal collagen cross-linking (CXL). METHODS Forty-eight eyes of 32 patients (18 males, 16-28 years) affected by progressive keratoconus in different stages of evolution underwent CXL using the standard epithelium-off protocol. Corneal thickness and corneal curvature before CXL and after 6 and 12 months using the Sirius tomographer were analyzed. The values of the mean corneal thickness at the corneal apex (CAT), center of the pupil (PCT), thinnest point (CTTL) and along concentric circles of 2, 4, 6, 8, 8.5, 9, 9.5 and 10 mm diameter were evaluated; the values of the mean curvature at the corneal apex and at the points in which the inferior, superior, nasal and temporal meridians crossed the above-mentioned concentric circles were also evaluated. RESULTS The mean preoperative values for CAT, PCT and CTTL were 461.4 ± 30.3, 475.3 ± 30.5 and 441 ± 32.0, respectively. The values after 12 months of CXL were 444.6 ± 36.2, 451.6 ± 36.7 and 418.2 ± 41.4. The peripheral corneal thickness at the eight points ranged from 479 to 733 preoperatively. At 12-month post-CXL, the values ranged from 444.6 to 734.1. The mean posterior curvature from apex to periphery ranged from - 4.5 to - 9.1 days preoperatively and from - 4.5 to - 9.2 days at 12 months. These were not statistically significant (ANOVA and unpaired T test). CONCLUSIONS Our data suggest that CXL over an 8-mm zone can stabilize the peripheral cornea. Longer-term follow-up studies on the peripheral cornea after CXL will provide useful information.
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Affiliation(s)
- C Cagini
- Ophthalmology Section, Department of Biomedical and Surgical Sciences, S. Maria della Misericordia Hospital, University of Perugia, Piazza Menghini 1, S. Andrea delle Fratte, 06156, Perugia, Italy.
| | - G Di Lascio
- Ophthalmology Section, Department of Biomedical and Surgical Sciences, S. Maria della Misericordia Hospital, University of Perugia, Piazza Menghini 1, S. Andrea delle Fratte, 06156, Perugia, Italy
| | - M Messina
- Ophthalmology Section, Department of Biomedical and Surgical Sciences, S. Maria della Misericordia Hospital, University of Perugia, Piazza Menghini 1, S. Andrea delle Fratte, 06156, Perugia, Italy
- Section of Academic Ophthalmology, Division of Clinical Neuroscience, Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham, UK
| | - F Riccitelli
- Ophthalmology Section, Department of Biomedical and Surgical Sciences, S. Maria della Misericordia Hospital, University of Perugia, Piazza Menghini 1, S. Andrea delle Fratte, 06156, Perugia, Italy
| | - H S Dua
- Section of Academic Ophthalmology, Division of Clinical Neuroscience, Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham, UK
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Gu L, Shan T, Ma YX, Tay FR, Niu L. Novel Biomedical Applications of Crosslinked Collagen. Trends Biotechnol 2018; 37:464-491. [PMID: 30447877 DOI: 10.1016/j.tibtech.2018.10.007] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 10/19/2018] [Accepted: 10/19/2018] [Indexed: 02/08/2023]
Abstract
Collagen is one of the most useful biopolymers because of its low immunogenicity and biocompatibility. The biomedical potential of natural collagen is limited by its poor mechanical strength, thermal stability, and enzyme resistance, but exogenous chemical, physical, or biological crosslinks have been used to modify the molecular structure of collagen to minimize degradation and enhance mechanical stability. Although crosslinked collagen-based materials have been widely used in biomedicine, there is no standard crosslinking protocol that can achieve a perfect balance between stability and functional remodeling of collagen. Understanding the role of crosslinking agents in the modification of collagen performance and their potential biomedical applications are crucial for developing novel collagen-based biopolymers for therapeutic gain.
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Affiliation(s)
- Lisha Gu
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, PR China
| | - Tiantian Shan
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, PR China
| | - Yu-Xuan Ma
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, PR China
| | - Franklin R Tay
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, PR China; The Dental College of Georgia, Augusta University, Augusta, GA, USA.
| | - Lina Niu
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, PR China; The Dental College of Georgia, Augusta University, Augusta, GA, USA.
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Lorenzo-Martín E, Gallego-Muñoz P, Ibares-Frías L, Marcos S, Pérez-Merino P, Fernández I, Kochevar IE, Martínez-García MC. Rose Bengal and Green Light Versus Riboflavin–UVA Cross-Linking: Corneal Wound Repair Response. ACTA ACUST UNITED AC 2018; 59:4821-4830. [DOI: 10.1167/iovs.18-24881] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Elvira Lorenzo-Martín
- Departamento de Biología Celular, Histología y Farmacología, GIR de Técnicas Ópticas para el Diagnóstico, Universidad de Valladolid, Valladolid, Spain
| | - Patricia Gallego-Muñoz
- Departamento de Biología Celular, Histología y Farmacología, GIR de Técnicas Ópticas para el Diagnóstico, Universidad de Valladolid, Valladolid, Spain
| | - Lucía Ibares-Frías
- Departamento de Biología Celular, Histología y Farmacología, GIR de Técnicas Ópticas para el Diagnóstico, Universidad de Valladolid, Valladolid, Spain
- Departamento de Oftalmología, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Susana Marcos
- Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Pablo Pérez-Merino
- Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Itziar Fernández
- Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, Spain
| | - Irene E. Kochevar
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - M. Carmen Martínez-García
- Departamento de Biología Celular, Histología y Farmacología, GIR de Técnicas Ópticas para el Diagnóstico, Universidad de Valladolid, Valladolid, Spain
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Ohana O, Kaiserman I, Domniz Y, Cohen E, Franco O, Sela T, Munzer G, Varssano D. Outcomes of simultaneous photorefractive keratectomy and collagen crosslinking. Can J Ophthalmol 2018; 53:523-528. [DOI: 10.1016/j.jcjo.2017.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 09/16/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
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Appropriate Sequence of Combined Intracorneal Ring Implantation and Corneal Collagen Cross-Linking in Keratoconus: A Systematic Review and Meta-Analysis. Cornea 2018; 37:1601-1607. [DOI: 10.1097/ico.0000000000001740] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Erlangga MD, Mahayana IT, Fachiroh J, Agni AN, Supartoto A, Pawiroranu S. Changes in interleukin-6 tear concentration and clinical outcome in moderate-to-severe bacterial corneal ulcers after corneal collagen cross-linking. Int J Ophthalmol 2018; 11:1421-1424. [PMID: 30140651 DOI: 10.18240/ijo.2018.08.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 01/23/2018] [Indexed: 12/31/2022] Open
Abstract
We aimed to evaluate interleukin-6 (IL-6) tear concentration and clinical outcome in patients with moderate-to-severe bacterial corneal ulcers post corneal collagen cross-linking (CXL) therapy. This pre-post designed study involving 21 moderate-to-severe corneal ulcer patients who underwent CXL therapy. Patients with infectious corneal ulcer were given CXL therapy as adjunctive treatment after 5d of broadspectrum antibiotic treatment. Patients with moderate to severe infectious bacterial corneal ulcers were included in this study. Tear sampling was performed before CXL therapy, using sterile Schimer paper from conjunctival inferior fornix. CXL therapy was performed in accordance with the CXL Dresden protocol. Data recording and tear sampling were then performed at day 1 and day 7 after CXL therapy. Data recording included, presence of conjunctival hyperemia, visual analogue scale (VAS), size of corneal defects, and decemetocele. There was a decrease in IL-6 tear concentration by day 7 after CXL therapy (P=0.001). IL-6 concentration at 1h after therapy (2274.67±2120.46 pg/mL) tended to be lower than before therapy (4330.09±3169.70 pg/mL), but the difference was not statistically significant (P=0.821). The size of corneal defects decreased significantly post CXL (P=0.007). The logMAR visual acuity before and after CXL therapy was not found to be significantly different (P=0.277). There was a significant decrease in VAS values (P=0.018) and blepharospasm (P=0.011) pre and post CXL. There was no significant decrease in conjunctival hyperemia pre and post CXL (P=0.293). There was significant reduction in IL-6 tear concentration and clinical improvement in moderate-to-severe bacterial corneal ulcers which underwent CXL therapy.
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Affiliation(s)
- Marzarendra Dhion Erlangga
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada/Dr. Sardjito General Hospital, Yogyakarta 55284, Indonesia
| | - Indra Tri Mahayana
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada/Dr. Sardjito General Hospital, Yogyakarta 55284, Indonesia
| | - Jajah Fachiroh
- Department of Biomolecular and Cell Biology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta 55284, Indonesia
| | - Angela Nurini Agni
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada/Dr. Sardjito General Hospital, Yogyakarta 55284, Indonesia
| | - Agus Supartoto
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada/Dr. Sardjito General Hospital, Yogyakarta 55284, Indonesia
| | - Suhardjo Pawiroranu
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada/Dr. Sardjito General Hospital, Yogyakarta 55284, Indonesia
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O'Brart NAL, O'Brart DPS, Aldahlawi NH, Hayes S, Meek KM. An Investigation of the Effects of Riboflavin Concentration on the Efficacy of Corneal Cross-Linking Using an Enzymatic Resistance Model in Porcine Corneas. Invest Ophthalmol Vis Sci 2018; 59:1058-1065. [PMID: 29490342 PMCID: PMC6436846 DOI: 10.1167/iovs.17-22994] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose To investigate riboflavin concentration on enzymatic resistance following corneal cross-linking (CXL). Methods Ninety-six porcine eyes were divided into five groups in two treatment runs. Group 1 remained untreated. Group 2 received riboflavin 0.05%, group 3 riboflavin 0.1%, group 4 riboflavin 0.2%, and group 5 riboflavin 0.3%. Treated eyes underwent CXL with ultraviolet A at 9 mW/cm2 for 10 minutes. Eight-millimeter discs from each cornea were submerged in pepsin digest solution. In the first run, disc diameters were measured daily. After 10 days, dry weights were recorded from five samples in each group. In the second run, dry weights were recorded in five samples in each group at 10 and 20 days. Results CXL-treated corneas took longer to digest than untreated (P < 0.001). Although eyes treated with higher riboflavin concentrations generally took longer to digest, there were no significant differences between groups (P = 0.3). Dry weights at 10 days demonstrated, with each increase in concentration, an increase in weight of residual undigested tissue (P < 0.001). In the second run, with each increase in riboflavin concentration there was an increase in weight of residual tissue (P < 0.001) at 10 days. At 20 days, the dry weight was lower with 0.05% riboflavin compared to 0.3% (P < 0.001) and 0.2% and 0.1% solutions (P < 0.05), with no other difference between groups. Conclusions There is a consistent dose-response curve with higher concentrations of riboflavin achieving greater CXL efficacy, suggesting that manipulation of riboflavin dosage as well as the UVA protocol can be used to optimize CXL.
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Affiliation(s)
| | - David P S O'Brart
- Keratoconus Research Institute, Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom
| | - Nada H Aldahlawi
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
| | - Sally Hayes
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
| | - Keith M Meek
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff
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Epi-Off versus Epi-On Corneal Collagen Cross-Linking in Keratoconus Patients: A Comparative Study through 2-Year Follow-Up. J Ophthalmol 2018; 2018:4947983. [PMID: 30151277 PMCID: PMC6087595 DOI: 10.1155/2018/4947983] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 04/29/2018] [Indexed: 11/26/2022] Open
Abstract
Aim To evaluate two different techniques of cross-linking: standard epithelium-off (CXL epi-off) versus transepithelial (CXL epi-on) cross-linking in patient with progressive keratoconus. Methods Forty eyes from 32 patients with progressive keratoconus were prospectively enrolled from June 2014 to June 2015 in this nonblinded, randomized comparative study. Twenty eyes were treated by CXL epi-off and 20 by CLX epi-on, randomly assigned, and followed for 2 years. All patients underwent a complete ophthalmologic testing that included uncorrected and best corrected visual acuity, central and peripheral corneal thickness, corneal astigmatism, simulated maximum, minimum, and average keratometry, corneal confocal microscopy, Schirmer I and break-up time (BUT) tests, and the Ocular Surface Disease Index. Intra- and postoperative complications were recorded. The solution used for CXL epi-off comprised riboflavin 0.1% and dextran 20.0% (Ricrolin), whereas the solution for CXL epi-on (Ricrolin TE) comprised riboflavin 0.1%, dextran 15.0%, trometamol (Tris), and ethylenediaminetetraacetic acid. Ultraviolet-A treatment was performed with a UV-X system at 3 mW/cm2. Results In both groups, a significant improvement in visual function (Group 1: baseline 0.36 ± 0.16 logMAR, two-year follow-up 0.22 ± 0.17 logMAR, p=0.01; Group 2: baseline 0.32 ± 0.18 logMAR, 2-year follow-up 0.27 ± 0.19 logMAR, p=0.01) was recorded. Keratometry remained unchanged in both groups. The mean corneal thickness showed a significant reduction (mean difference of corneal thickness: −55 micron and −71 micron, resp.). One-month after treatment, OSDI© reached 13.56 ± 2.15 in Group 1 (p=0.03) and 11.26 ± 2.12 in Group 2 (p=0.04). At confocal microscopy, abnormal corneal nerve alterations were found in both groups. Fibrotic reaction (43.75%) and activated keratocyte (62.6%) were more commonly recorded in Group 1 than in Group 2 (25.0% and 18.75%), with p=0.668 and 0.356, respectively. Conclusion Our findings demonstrate that both procedures are able to slow keratoconus progression. Both treatment modalities are equivalent in terms of results and related complications. CXL epi-on technique is preferable to CXL epi-off since it preserves the corneal thickness and improves visual acuity, also reducing the postoperative ocular discomfort during the study period.
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Mastropasqua L, Nubile M, Salgari N, Mastropasqua R. Femtosecond Laser-Assisted Stromal Lenticule Addition Keratoplasty for the Treatment of Advanced Keratoconus: A Preliminary Study. J Refract Surg 2018; 34:36-44. [PMID: 29315440 DOI: 10.3928/1081597x-20171004-04] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/21/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the in vivo effect of a novel femtosecond laser-assisted procedure termed stromal lenticule addition keratoplasty for advanced keratoconus. METHODS Ten patients with stage III and IV stable keratoconus were included. Negative meniscus-shaped stromal lenticules were produced from corneoscleral eye bank buttons with a refractive lenticule extraction procedure with a 500-kHz VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany). Recipient corneas underwent a modified femtosecond laser flap-cut procedure to produce an intrastromal pocket and lenticules were implanted. Patients were followed up for 6 months after surgery with determination of uncorrected (UDVA) and corrected (CDVA) distance visual acuity, subjective refraction and topographic corneal curvature changes, anterior segment optical coherence tomography (AS-OCT), and in vivo confocal microscopy. RESULTS Comparison of preoperative and 6-month postoperative UDVA and CDVA showed statistically significant improvements (P = .024 and .007, respectively) from 1.58 ± 0.36 to 1.22 ± 0.37 and from 1.07 ± 0.17 to 0.70 ± 0.23 logMAR. Eight of 10 eyes showed an improvement in UDVA (P < .001) that ranged between one and three lines, whereas all but one eye presented improved CDVA. Corneal topography documented a decrease between preoperative and 6-month postoperative anterior mean curvature (AVG-K at 3 mm) and anterior Q values (P = .005). AS-OCT showed a significant increase in thickness of the central and mid-peripheral cornea produced by the lenticule implantation (P = .005). CONCLUSIONS The stromal lenticule addition keratoplasty procedure was clinically efficient in improving the corneal shape and vision in patients with keratoconus. Negative meniscus-shaped lenticule addition induced a flattening of the cone while increasing corneal thickness. [J Refract Surg. 2018;34(1):36-44.].
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Sharif R, Fowler B, Karamichos D. Collagen cross-linking impact on keratoconus extracellular matrix. PLoS One 2018; 13:e0200704. [PMID: 30020979 PMCID: PMC6051648 DOI: 10.1371/journal.pone.0200704] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 06/19/2018] [Indexed: 01/16/2023] Open
Abstract
Background Keratoconus (KC) is a common multifactorial ectatic corneal disease with unknown onset. KC most commonly appears in adolescence and affects approximately 1:400 people worldwide. Treatment options, for advanced KC cases, are collagen cross-linking (CXL) and corneal transplants. CXL is a new KC treatment that helps arrest the disease. Unfortunately, only a fraction of KC patients will qualify for CXL treatment. Our goal, in this study, was to begin to understand how CXL affects the corneal microenvironment and pave the way towards a more patient-driven CXL treatment. Methods Primary human corneal fibroblasts from healthy and KC donors were plated on transwell polycarbonate membranes and stimulated by a stable vitamin C. At 4 weeks, riboflavin was added followed by UVA irradiation. Transmission Electron Microscopy (TEM) and western blots were used to assess the effect of CXL on the extracellular matrix (ECM) and the resident cells, pre- and post CXL. Results Data shows CXL improved lamellar organization showing more organized collagen fibrils decorated with proteoglycans (PGs). The distribution of the collagen fibrils and interfibrillar spacing was also visibly improved, post-CXL. Lumican, mimecan, and decorin were the dominant PGs and were significantly upregulated in post-CXL cultures. ECM degradation proteins, matrix metalloproteinases (MMPs), MMP-1, -3, and -9, but not MMP-2, were significantly downregulated post-CXL. TIMP-1 and -2 were not modulated by CXL. Conclusion The unknown effects of CXL on the human corneal microenvironment have hampered our ability to make CXL available to all KC patients. Our current study provides a deeper understanding on CXL activity, using our unique 3D in vitro model.
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Affiliation(s)
- Rabab Sharif
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - Ben Fowler
- Oklahoma Medical Research Foundation (OMRF), Imaging Core Facility, Oklahoma City, OK, United States of America
| | - Dimitrios Karamichos
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
- * E-mail:
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Conventional Corneal Collagen Cross-Linking Versus Transepithelial Diluted Alcohol and Iontophoresis-Assisted Corneal Cross-Linking in Progressive Keratoconus. Cornea 2018; 36:1492-1497. [PMID: 28922329 DOI: 10.1097/ico.0000000000001383] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To compare clinical outcomes of conventional corneal cross-linking (C-CXL) and diluted alcohol and iontophoresis-assisted corneal cross-linking (DAI-CXL) for the treatment of progressive keratoconus (KC). METHODS Ninety-three eyes of 80 patients with KC were treated by C-CXL (n = 47) or DAI-CXL (n = 46). Visual acuity, keratometry, KC indexes, pachymetry, and aberrations were recorded before treatment and 1, 3, 6, and 12 months after treatment. The demarcation line was assessed 1 month after treatment. RESULTS A significant improvement in visual acuity was observed at month 3 and month 6 after DAI-CXL and C-CXL, respectively. A significant decrease in maximum keratometry was observed in both groups at month 6. The front symmetry index significantly improved in both groups after 6 months, whereas the Baiocchi Calossi Versaci index significantly improved only after DAI-CXL at month 12 (P = 0.01). Average keratometry and other KC indexes were stable during 12 months of follow-up. Central corneal thickness decreased by 28.6 and 40.2 μm after DAI-CXL and C-CXL at month 1, respectively (P < 0.01), and it reached baseline at the 12th month (P = 0.14) only in the DAI-CXL group. Higher-order aberrations, coma, and spherical aberration significantly worsened at month 1 (P < 0.01) only after C-CXL; however, they improved significantly at month 12 compared with baseline (P < 0.05) in both groups. The demarcation line was visible in all cases at month 1 at a mean depth of 302 ± 56 μm and 311 ± 57 μm after DAI-CXL and C-CXL, respectively (P = 0.7). CONCLUSIONS The DAI-CXL protocol seems as effective as the C-CXL protocol in halting KC progression after 1 year of follow-up.
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Subasinghe SK, Ogbuehi KC, Dias GJ. Current perspectives on corneal collagen crosslinking (CXL). Graefes Arch Clin Exp Ophthalmol 2018; 256:1363-1384. [PMID: 29623463 DOI: 10.1007/s00417-018-3966-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 02/20/2018] [Accepted: 03/23/2018] [Indexed: 12/13/2022] Open
Abstract
Corneal collagen crosslinking has revolutionized the treatment of keratoconus and post-refractive corneal ectasia in the past decade. Corneal crosslinking with riboflavin and ultraviolet A is proposed to halt the progression of keratectasia. In the original "Conventional Dresden Protocol" (C-CXL), the epithelium is removed prior to the crosslinking process to facilitate better absorption of riboflavin into the corneal stroma. Studies analyzing its short- and long-term outcomes revealed that although there are inconsistencies as to the effectiveness of this technique, the advantages prevail over the disadvantages. Therefore, corneal crosslinking (CXL) is widely used in current practice to treat keratoconus. In an attempt to improve the visual and topographical outcomes of C-CXL and to minimize time-related discomfort and endothelial-related side effects, various modifications such as accelerated crosslinking and transepithelial crosslinking methods have been introduced. The comparison of outcomes of these modified techniques with C-CXL has also returned contradictory results. Hence, it is difficult to clearly identify an optimal procedure that can overcome issues associated with the CXL. This review provides an up-to-date analysis on clinical and laboratory findings of these popular crosslinking protocols used in the treatment of keratoconus. It is evident from this review that in general, these modified techniques have succeeded in minimizing the immediate complications of the C-CXL technique. However, there were contradictory viewpoints regarding their effectiveness when compared with the conventional technique. Therefore, these modified techniques need to be further investigated to arrive at an optimal treatment option for keratoconus.
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Affiliation(s)
- Sandeepani K Subasinghe
- Department of Anatomy, University of Otago, P.O. Box 913, 270 Great King Street, Dunedin, 9054, New Zealand.
| | - Kelechi C Ogbuehi
- Ophthalmology Section, Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - George J Dias
- Department of Anatomy, University of Otago, P.O. Box 913, 270 Great King Street, Dunedin, 9054, New Zealand
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Abstract
In patients with keratoconus, a progressive, ectatic disease of the cornea, the shape of the cornea is continuously changing leading to a reduction in visual acuity by progressive myopia and more and more (irregular) astigmatism. The symptomatic treatment consists of the prescription of glasses or special gas-permeable rigid contact lenses. Corneal tomography is generally used for diagnosis. After initial diagnosis of keratoconus, regular tomographic follow-ups should be performed. If clinically significant progression is found and confirmed by repeated measurements, riboflavin UVA collagen crosslinking should be offered to the patients. The aim of riboflavin UVA collagen crosslinking is to halt the progression of the disease to avoid further complications. The therapeutic principle is a combined effect of the photosensitizer riboflavin and UVA light. This stiffening effect of the corneal tissue halts the progression of keratoconus. The efficacy of this treatment has been demonstrated in various randomized, controlled trials.
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Affiliation(s)
- P Maier
- Klinik für Augenheilkunde, Universitätsklinikum Freiburg, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Killianstr. 5, 79106, Freiburg, Deutschland.
| | - T Reinhard
- Klinik für Augenheilkunde, Universitätsklinikum Freiburg, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Killianstr. 5, 79106, Freiburg, Deutschland
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Al-Amri AM. 5-year follow-up of combined non-topography guided photorefractive keratectomy and corneal collagen cross linking for keratoconus. Int J Ophthalmol 2018; 11:48-52. [PMID: 29375990 DOI: 10.18240/ijo.2018.01.09] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 09/10/2017] [Indexed: 11/23/2022] Open
Abstract
AIM To evaluate the visual outcomes of simultaneous non-topography guided photorefractive keratectomy (PRK) and corneal collagen cross-linking (CXL) in eyes with keratoconus 5y after the procedure. METHODS Prospective, interventional, non-randomized, and non-controlled case series design was used. Sixty eyes of 30 patients (16 males and 14 females; age: 21-41y) with mild, non-progressive (stages 1-2) keratoconus were enrolled. Refraction, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), flat and steep keratometry readings, and adverse events were evaluated preoperatively and postoperatively. Data were collected preoperatively and postoperatively at 3mo, 1, 2, 3, 4, and 5y follow-up visits after combined non-topography-guided PRK with CXL was performed. All patients had at least 5y of follow-up. RESULTS All study parameters showed a statistically significant improvement at 5y over baseline values. The mean follow-up time was 68.20±4.71mo (range: 60-106mo). Patients showed a significant improvement in UDVA from 1.24±0.79 logMAR prior to combined non-TG-PRK+CXL to 0.06±0.15 logMAR postoperatively at the time of their last follow-up visit. CDVA significantly increased from 0.06±0.19 logMAR preoperatively to 0.03±0.12 logMAR postoperatively. A significant decrease in the mean spherical equivalent (SE) refraction was observed from -2.28±1.8 to -0.79±0.93 diopters (D) (P<0.05), and the manifest sphere decreased from -1.62±1.23 to -0.27±0.21 D (P=0.001). The manifest cylinder significantly decreased from -1.73±0.86 to -0.29±0.34 D postoperatively (P=0.001). The mean steep keratometry was 45.13±1.32 vs 47.28±2.12 D preoperatively (P<0.05), and the preoperative mean steepest keratometry (Kmax) 48.6±3.1 was reduced significantly to 46.8±2.9 postoperatively (P<0.05). CONCLUSION Combined non-TG-PRK with 15min CXL is an effective and safe option for correcting mild refractive error and improving visual acuity in patients with mild stable keratoconus.
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Comparative efficacy of two different topical povidone-iodine 5% regimens in reducing conjunctival bacterial flora: A randomized parallel double-masked clinical trial. PLoS One 2017; 12:e0189206. [PMID: 29261737 PMCID: PMC5736199 DOI: 10.1371/journal.pone.0189206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 11/18/2017] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION The increasing prevalence of multi-resistant bacteria is a major public health concern. Infections acquired during ophthalmic surgery are devastating. The purpose of the current study is to compare the proportion of eyes with negative bacterial cultures on all tested media after 1 versus 3 sequential drops of povidone-iodine (PI) 5% into the inferior conjunctival fornix. METHODS Patients were randomly assigned to receive 1 (PI group) drop (at time 28 minutes) or 3 (PI plus group) sequential drops (at time 0, 20 minutes and 28 minutes) of PI 5% into the inferior conjunctival sac of one randomly selected eye. A swab culture was obtained from the inferior conjunctival fornix 5 minutes before and 30 minutes after time 0. Central corneal thickness (CCT) was measured shortly before time 0 and shortly after time 30. Conjunctival swabs were incubated aerobically in enriched Thioglycolate liquid medium (meat broth) and in three solid culture media (chocolate agar, trypticase soy agar with 5% sheep blood, and Sabouraud agar). RESULTS There was no significant difference in the proportion of negative cultures after intervention between groups (p = 0.1638). Also in the PI group (n = 59), the proportion of eyes with negative cultures after PI (79.7%) did not differ significantly from baseline (76.3%; p = 0.7539). However in the PI plus group (n = 61), the proportion of eyes with all negative cultures after PI (85.3%) was significantly higher than before PI (70.5%) (p = 0.0177). There was no significant difference in mean CCT before and after the intervention in both groups. CONCLUSION Instillation of 3 sequential drops of PI was associated with a significant increase in the proportion of eyes with all negative cultures, while instillation of a single drop of PI was not associated with a significant increase in the proportion of negative cultures. Further study is warranted to determine whether the difference between the PI administration regimens is also associated with differences in the rates of postoperative ocular infections.
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Sharif R, Hjortdal J, Sejersen H, Frank G, Karamichos D. Human in vitro Model Reveals the Effects of Collagen Cross-linking on Keratoconus Pathogenesis. Sci Rep 2017; 7:12517. [PMID: 28970517 PMCID: PMC5624875 DOI: 10.1038/s41598-017-12598-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 09/06/2017] [Indexed: 12/11/2022] Open
Abstract
Keratoconus (KC) is a corneal thinning disorder that leads to severe vision impairment As opposed to corneal transplantation; corneal collagen crosslinking (CXL) is a relatively non-invasive procedure that leads to an increase in corneal stiffness. In order to evaluate the effect of CXL on human corneal stromal cells in vitro, we developed a 3-D in vitro CXL model, using primary Human corneal fibroblasts (HCFs) from healthy patients and Human Keratoconus fibroblasts (HKCs) from KC patients. Cells were plated on transwell polycarbonate membranes and stimulated by a stable vitamin C. CXL was performed using a mixed riboflavin 0.1% PBS solution followed by UVA irradiation. Our data revealed no significant apoptosis in either HCFs or HKCs following CXL. However, corneal fibrosis markers, Collagen III and α-smooth muscle actin, were significantly downregulated in CXL HKCs. Furthermore, a significant downregulation was seen in SMAD3, SMAD7, and phosphorylated SMADs -2 and -3 expression in CXL HKCs, contrary to a significant upregulation in both SMAD2 and Lysyl oxidase expression, compared to HCFs. Our novel 3-D in vitro model can be utilized to determine the cellular and molecular effects on the human corneal stroma post CXL, and promises to establish optimized treatment modalities in patients with KC.
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Affiliation(s)
- Rabab Sharif
- Department of Cell Biology, University of Oklahoma Health science Center, Oklahoma City, Oklahoma, USA
| | - Jesper Hjortdal
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark
| | - Henrik Sejersen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark
| | - Garett Frank
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, USA
| | - Dimitrios Karamichos
- Department of Cell Biology, University of Oklahoma Health science Center, Oklahoma City, Oklahoma, USA.
- Department of Ophthalmology/Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, USA.
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