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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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Sozer O, Ozalp O, Atalay E, Demir SS, Alatas İO, Yildirim N. Comparison of blood levels of vitamin B12, folic acid, riboflavin, and homocysteine in keratoconus and healthy subjects. J Cataract Refract Surg 2023; 49:589-594. [PMID: 36745841 DOI: 10.1097/j.jcrs.0000000000001160] [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: 10/03/2022] [Accepted: 01/30/2023] [Indexed: 02/08/2023]
Abstract
PURPOSE To evaluate blood levels of vitamin B12, folic acid, riboflavin, and homocysteine in keratoconus (KC) and healthy subjects. SETTING Eskişehir Osmangazi University, Eskişehir, Turkey. DESIGN Cross-sectional study. METHODS 100 KC patients (patient group) between the ages of 18 to 35 years and 200 healthy individuals (control group) in the same age range were included in the Eskişehir Osmangazi University Hospital Eye Clinic between October 2019 and March 2020. In all cases, a complete ophthalmologic examination and corneal tomography evaluation with a Pentacam Scheimpflug camera were performed. In blood samples, vitamin B12 and folic acid levels were measured using an electrochemiluminescence immunoassay analyzer, and homocysteine and riboflavin levels were measured using high-performance liquid chromatography. Chi-square tests were used in the analysis of categorical variables, and Mann-Whitney U and Kruskal-Wallis tests were used in the analysis of numerical variables. RESULTS Homocysteine (13.0 ± 6.6 vs 12.1 ± 5.4 μmol/L, P = .190), vitamin B12 (313.5 ± 119.4 vs 322.9 ± 128.3 pg/mL, P = .619), and folic acid (7.0 ± 2.7 vs 7.4 ± 2.9 ng/mL, P = .230) levels were not different between KC (100 eyes of 100 subjects) and control (200 eyes of 200 subjects) groups. The mean riboflavin level was 84.0 ± 21.8 μg/L in the patient group and 183.6 ± 74.3 μg/L in the control group, with a significant difference between the 2 groups ( P < .001). Riboflavin levels were below 180 μg/L in 99% (n = 99) of the cases in the KC group and 53.5% (n = 107) in the control group ( P < .001). CONCLUSIONS Low blood riboflavin levels in KC patients may be a possible risk factor in the pathogenesis of KC.
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Affiliation(s)
- Omer Sozer
- From the Ophthalmology Clinic, Emirdag State Hospital, Afyonkarahisar, Turkey (Sozer); Ophthalmology Clinic, Private Gürlife Hospital, Eskişehir, Turkey (Ozalp); Department of Ophthalmology, Eskişehir Osmangazi University Medical School, Eskişehir, Turkey (Atalay, Yildirim); Medical Biochemistry Clinic, Sandikli State Hospital, Afyonkarahisar, Turkey (Demir); Department of Medical Biochemistry, Eskişehir Osmangazi University Medical School, Eskişehir, Turkey (Alatas)
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Cronin B, Ghosh A, Chang CY. Oxygen-supplemented transepithelial-accelerated corneal crosslinking with pulsed irradiation for progressive keratoconus: 1 year outcomes. J Cataract Refract Surg 2022; 48:1175-1182. [PMID: 35383648 DOI: 10.1097/j.jcrs.0000000000000952] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 03/29/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the effects of combining oxygen supplementation with enhanced UV-A light and increased riboflavin permeability in improving the efficacy of epithelium-on crosslinking (epi-on CXL). SETTING Private eye clinic in Brisbane, Queensland, Australia. DESIGN Retrospective single-center nonrandomized uncontrolled longitudinal cohort case series. METHODS Transepithelial CXL was performed on keratoconic eyes. Applications of an oxygen goggle and pulsed UV-A irradiation (1 second on, 1 second off) were used to enhance oxygen kinetics during epi-on CXL. Additional procedural modifications included the use of benzalkonium chloride and high UV-A irradiance level (30 mW/cm 2 ) to improve the stromal bioavailability of riboflavin and UV-A. The main efficacy outcomes were the changes in mean corrected distance visual acuity (CDVA) and safety over 12 months. Additional refractive and keratometry (K) outcomes were also observed. RESULTS 53 eyes (38 patients) were included in this study. 12 months postoperatively, mean CDVA improved from a mean of 0.18 ± 0.2 at baseline to 0.07 ± 0.1 logMAR ( P < .0001). No statistically significant change was observed in maximum K (Kmax) and mean K, which were respectively 51.7 ± 5.8 diopters (D) and 46.4 ± 3.85 D at baseline and 51.2 ± 5.7 D ( P = .152) and 46.0 ± 3.84 D ( P = .06) 12 months postoperatively. Only 3 eyes experienced an increase of more than 2 D in Kmax; however, none of these eyes experienced a CDVA loss. There were no reported infections, corneal scarring, or other severe adverse effects. CONCLUSIONS Performing supplemental oxygen epi-on CXL with accelerated, pulsed UV-A irradiation in conjunction with riboflavin permeability enhancers resulted in improved CDVA ( P < .0001) and stable keratometry up to 12 months postoperatively with a good safety profile.
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Affiliation(s)
- Brendan Cronin
- From the Queensland Eye Institute, Brisbane, Queensland, Australia (Cronin, Ghosh); Glaukos Corp., Medical Affairs, Burlington, Massachusetts (Chang); Wills Eye Hospital, Cornea Service, Philadelphia, Pennsylvania (Chang)
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Comparison of pulsed and continuous accelerated corneal crosslinking for keratoconus: 1-year results at a single center. J Cataract Refract Surg 2021; 47:641-648. [PMID: 33196569 DOI: 10.1097/j.jcrs.0000000000000488] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 10/11/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare the clinical outcomes between pulsed and continuous accelerated crosslinking (CXL) for keratoconus. SETTING Hospital. DESIGN Retrospective comparison study. METHODS Korean patients who were treated for keratoconus between September 2015 and January 2018 at Seoul St. Mary's Hospital were included. Eyes were subjected to pulsed accelerated crosslinking (30 mW/cm2 for 8 minutes, 1 second on/1 second off) or continuous accelerated crosslinking (30 mW/cm2 for 4 minutes; delivering 7.2 J/cm2). Outcomes were evaluated after 1 year. RESULTS At 1 year, the 2 groups did not exhibit changes in their corrected and uncorrected distance visual acuity values. The pulsed group (25 eyes in 25 patients) exhibited significantly improved values for sphere (P = .009) and spherical equivalent (P = .033), although no statistically significant difference was observed in the continuous group (20 eyes in 20 patients). All keratometry (k)values (SimKf, SimKs, SimKmean, and Kmax) improved in both groups (all P < .05), although the pulsed group had significantly greater changes in the SimKmean value (P = .036) and the Kmax value (P = .03). Both groups had significantly decreased central and thinnest corneal thicknesses (all P < .001), although the pulsed group had a substantially lower thinnest corneal thickness (P = .017). Corneal densitometry measured using the Pentacam device increased in both groups (all P < .001), with a higher densitometry value in the pulsed group (P = .013). Furthermore, the depth of the demarcation line was deeper in the pulsed group (P = .015). CONCLUSIONS Pulsed accelerated crosslinking might provide better postcrosslinking effects than continuous accelerated crosslinking.
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Aytekin E, Pehlivan SB. Corneal cross-linking approaches on keratoconus treatment. J Drug Deliv Sci Technol 2021. [DOI: 10.1016/j.jddst.2021.102524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Cheung IMY, Mcghee CNJ, Sherwin T. Beneficial effect of the antioxidant riboflavin on gene expression of extracellular matrix elements, antioxidants and oxidases in keratoconic stromal cells. Clin Exp Optom 2021; 97:349-55. [DOI: 10.1111/cxo.12138] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Revised: 11/28/2013] [Accepted: 12/04/2013] [Indexed: 12/23/2022] Open
Affiliation(s)
- Isabella M Y Cheung
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Charles N J Mcghee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Trevor Sherwin
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
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Ormonde S. Refractive surgery for keratoconus. Clin Exp Optom 2021; 96:173-82. [DOI: 10.1111/cxo.12051] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 01/31/2013] [Accepted: 02/03/2013] [Indexed: 11/28/2022] Open
Affiliation(s)
- Sue Ormonde
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand,
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Menon R, Menon S, Ajith T. Prevalence of subclinical keratoconus in children presenting with refractive errors: A cross-sectional study. KERALA JOURNAL OF OPHTHALMOLOGY 2021. [DOI: 10.4103/kjo.kjo_103_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Potential Protective and Therapeutic Roles of the Nrf2 Pathway in Ocular Diseases: An Update. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:9410952. [PMID: 32273949 PMCID: PMC7125500 DOI: 10.1155/2020/9410952] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 02/05/2020] [Indexed: 12/19/2022]
Abstract
Nuclear factor- (erythroid-derived 2-) like 2 (Nrf2) is a regulator of many processes of life, and it plays an important role in antioxidant, anti-inflammatory, and antifibrotic responses and in cancer. This review is focused on the potential mechanism of Nrf2 in the occurrence and development of ocular diseases. Also, several Nrf2 inducers, including noncoding RNAs and exogenous compounds, which control the expression of Nrf2 through different pathways, are discussed in ocular disease models and ocular cells, protecting them from dysfunctional changes. Therefore, Nrf2 might be a potential target of protecting ocular cells from various stresses and preventing ocular diseases.
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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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Pantalon A, Pfister M, Aranha dos Santos V, Sapeta S, Unterhuber A, Pircher N, Schmidinger G, Garhöfer G, Schmidl D, Schmetterer L, Werkmeister RM. Ultrahigh-resolution anterior segment optical coherence tomography for analysis of corneal microarchitecture during wound healing. Acta Ophthalmol 2019; 97:e761-e771. [PMID: 30762310 PMCID: PMC6767559 DOI: 10.1111/aos.14053] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 01/19/2019] [Indexed: 12/29/2022]
Abstract
PURPOSE To employ ultrahigh-resolution (UHR) optical coherence tomography (OCT) for investigation of the early wound healing process in corneal epithelium. METHODS A custom-built UHR-OCT system assessed epithelial healing in human keratoconic cornea after epi-off crosslinking (CXL) procedure and a wound healing model in rabbits with iatrogenic corneal injury. 3D OCT data sets enhanced obtaining epithelial thickness maps and evaluation of reepithelization stage. Accompanying changes in deeper corneal microarchitecture were analysed. RESULTS The mean central corneal thickness in 40 eyes with keratoconus at baseline was 482.7 ± 38.2 μm, while mean central epithelial thickness (CET) was 43.8 ± 6.4 μm. At the final visit 20 ± 5 days post-CXL procedure, CET was 35.0 ± 5.8 μm, significantly thinner after reepithelization (p < 0.001). Surgical success was assessed at the final visit through the demarcation line (DL), identified at 43.7 ± 13.5% stromal depth. In rabbits, the mean CET in 20 eyes at baseline was 35.9 ± 2.6 μm. In rabbits that revealed complete wound closure (10/20 eyes) at the last study day at 72 hr, CET was significantly thinner compared to baseline (30.4 ± 2.8 μm versus 35.4 ± 2.9 μm, p = 0.005). An intra-stromal landmark indicating early keratocyte apoptosis was measured at 30.0 ± 5.1% stromal depth. Epithelial thickness maps showed the time-course of corneal healing. CONCLUSION Ultrahigh-resolution (UHR)-OCT provided precise assessment of epithelial wound and its healing by 3D-mapping. In addition, microarchitectural changes in the cornea in early phases of epithelial healing were revealed.
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Affiliation(s)
- Anca Pantalon
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Department of OphthalmologyGr. T. Popa University of Medicine and PharmacyIasiRomania
| | - Martin Pfister
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Ocular and Dermal Effects of ThiomersMedical University of ViennaViennaAustria
| | | | - Sabina Sapeta
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Angelika Unterhuber
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Niklas Pircher
- Department of OphthalmologyMedical University of ViennaViennaAustria
| | | | - Gerhard Garhöfer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Doreen Schmidl
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Leopold Schmetterer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Ocular and Dermal Effects of ThiomersMedical University of ViennaViennaAustria
- Singapore Eye Research InstituteSingapore National Eye CentreSingaporeSingapore
- Ophthalmology and Visual Sciences Academic Clinical ProgramDuke‐NUS Medical SchoolSingaporeSingapore
- Ophthalmic Engineering & Innovation LaboratoryDepartment of Biomedical EngineeringFaculty of EngineeringNational University of SingaporeSingaporeSingapore
- Lee Kong Chian School of MedicineNanyang Technological UniversitySingaporeSingapore
| | - René M. Werkmeister
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Ocular and Dermal Effects of ThiomersMedical University of ViennaViennaAustria
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Abstract
Supplemental Digital Content is Available in the Text. Purpose: To map the publication trends in and explore hotspots of keratoconus research. Methods: A bibliometric analysis based on the Web of Science Core Collection was conducted to investigate the publication trends in research related to keratoconus. The records extracted were analyzed, and a knowledge map was constructed using VOSviewer v.1.6.10 to visualize the annual publication number, distribution of countries, international collaborations, author productivity, source journals, intellectual base, and research hotspots in the field of keratoconus. Results: In total, 3194 peer-reviewed publications on keratoconus published between 2009 and 2018 were retrieved, and the annual research output increased with time. The United States ranked the highest among the countries with the most publications, and Tehran University of Medical Sciences was the most active institution. JL Alio contributed to the most number of publications on keratoconus, and Cornea was the most prolific journal publishing keratoconus research. The top cited references mainly focused on corneal collagen cross-linking. The keywords formed 6 clusters: 1) pathogenesis of keratoconus, 2) corneal collagen cross-linking, 3) management for early-stage keratoconus, 4) corneal parameter measurement, 5) surgical treatment of keratoconus, and 6) corneal biomechanics-related research. Conclusions: On the basis of the data extracted from the Web of Science Core Collection, the quantity and quality of publications on keratoconus were assessed using bibliometric techniques. The cited references and research hotspots could provide insights into keratoconus research as well as valuable information to cornea specialists for performing research in this field and discovering potential collaborators.
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Kanellopoulos AJ. Management of progressive keratoconus with partial topography-guided PRK combined with refractive, customized CXL - a novel technique: the enhanced Athens protocol. Clin Ophthalmol 2019; 13:581-588. [PMID: 31040638 PMCID: PMC6453552 DOI: 10.2147/opth.s188517] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Purpose To report a novel application of partial topography-guided photorefractive keratectomy combined with topographically customized, higher fluence, and variable pattern corneal cross-linking applied on the same day of the treatment of keratoconus. Methods A topography-guided partial photorefractive keratectomy treatment of maximum 30 µm over the thinnest cone area was applied initially followed by a 7 mm, 50 µm phototherapeutic keratectomy treatment to address epithelial removal. 0.02% Mitomycin C was applied for 20 seconds and then the exposed stroma was soaked with 0.1% riboflavin solution for 5 minutes. The cornea was then treated with a customized, variable-pattern and 20 mW/cm2 fluence for a total of 5-10 J, and up to 15 J of energy was delivered with the KXL-II device employing an active tracker. The center of the pattern that received the 15 J was topography-matched with the thinnest area of the cone. Visual acuity, refractive error, cornea clarity, keratometry, topography, pachymetry with a multitude of modalities and endothelial cell density were evaluated over 36 months. Results Keratoconus was stabilized in all cases. The severity of keratoconus stage by Amsler- Krumeich criteria improved from an average of 3.2 (1-4) to 1.8 (0-3). Uncorrected distance visual acuity changed from preoperative 20/80 to 20/25 at 6 months. A maximum astigmatic reduction of 7.8 D (5.3-15.6), and a significant cornea surface normalization (an index of height decentration improvement from 0.155 [±0.065] to 0.045 [±0.042]) were achieved by 1 month and remained relatively stable for 36 months postoperatively. Two cases delayed full reepithelialization for up to 9 days. Conclusion This paper introduces a novel technique in order to maximize the refractive normalization effect along with ectasia stabilization in young keratoconus patients. This may facilitate the use of less tissue ablation, in comparison to utilizing a homogeneous UV light beam for corneal cross-linking in Athens Protocol cases. It broadens the number of potential candidate cases that would have been limited to employ this technique due to tissue thickness limitations.
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Affiliation(s)
- Anastasios John Kanellopoulos
- Department of Ophthalmology, LaserVision Clinical and Research Institute, Athens, Greece, .,Department of Ophthalmology, NYU Medical School, New York, NY, USA,
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Affiliation(s)
- David C. Paik
- Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, New York, United States
| | - Stephen L. Trokel
- Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, New York, United States
| | - Leejee H. Suh
- Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, New York, United States
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Karadağ AS, Bilgin B, Özdemir N. Keratokonus hastalarında UVA-Riboflavin korneal kollajen çapraz bağlama tedavisinin sonuçları. CUKUROVA MEDICAL JOURNAL 2018. [DOI: 10.17826/cumj.336939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Corneal Collagen Cross-Linking With Riboflavin and Ultraviolet A Light for Pediatric Keratoconus: Ten-Year Results. Cornea 2018; 37:560-566. [PMID: 29319598 DOI: 10.1097/ico.0000000000001505] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To assess the 10-year follow-up efficacy and safety of riboflavin ultraviolet A-induced cross-linking (CXL) in a population of pediatric patients aged 18 years and younger with progressive keratoconus (KC). METHODS The prospective longitudinal cohort study included 62 eyes of 47 keratoconic patients undergoing epithelium-off CXL who completed 10-year follow-up. The surgical procedure was performed in all patients according to the Siena (Dresden modified) protocol. Evaluation included uncorrected distance visual acuity, corrected distance visual acuity, Scheimpflug corneal tomography, and optical coherence tomography demarcation line measurement. Follow-up measurements taken up to 10 years after treatment were compared with baseline values, and statistical analysis was performed using a 2-tailed paired sample Student t test. RESULTS Uncorrected distance visual acuity and corrected distance visual acuity improved from 0.45 to 0.23 logarithm of the minimum angle resolution (P = 0.0001) and from 0.14 to 0.1 logarithm of the minimum angle resolution (P = 0.019). KC stability was recorded after 10 years of follow-up in nearly 80% of the patients. The overall 10-year follow-up progression rate was 24% including 13 eyes of 9 patients with Kmax progression over 1 diopter and 2 eyes of 2 patients who underwent corneal grafting. CONCLUSIONS The study demonstrates the ability of CXL to slow down KC progression in pediatric patients, improving functional performance. Long-term stability may be correlated with CXL-induced delay in corneal collagen turnover and with spontaneous age-related KC stabilization. A 24% regression rate could be contemplated in the patients who were aged 15 years and younger at the time of inclusion in the treatment protocol.
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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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Continuous-light versus pulsed-light accelerated corneal crosslinking with ultraviolet-A and riboflavin. J Cataract Refract Surg 2018; 44:382-389. [DOI: 10.1016/j.jcrs.2017.12.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 10/17/2017] [Accepted: 12/09/2017] [Indexed: 11/21/2022]
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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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Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection. JOURNAL OF BIOPHYSICS 2017; 2017:3057329. [PMID: 29158733 PMCID: PMC5660810 DOI: 10.1155/2017/3057329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/02/2017] [Accepted: 08/29/2017] [Indexed: 11/30/2022]
Abstract
In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm2 and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus, Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin.
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Delivery of Riboflavin-5'-Monophosphate Into the Cornea: Can Liposomes Provide Any Enhancement Effects? J Pharm Sci 2017; 106:3041-3049. [PMID: 28551428 DOI: 10.1016/j.xphs.2017.05.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/24/2017] [Accepted: 05/08/2017] [Indexed: 11/20/2022]
Abstract
Keratoconus is a progressive condition caused by the thinning of the cornea, which eventually deforms the front surface of the eye into a cone shape leading to ghosting, multiple images, glare, and several other vision problems. Currently, keratoconus is treated with UV-induced riboflavin (Rb)-mediated collagen cross-linking, which requires a physical removal of the corneal epithelium under topical anesthesia. This study reports the penetration of Rb and its more water-soluble form, riboflavin-5'-monophosphate (RbP), into the bovine cornea ex vivo. Using ex vivo bovine corneal tissues and 0.8 mg/mL drug solutions in phosphate buffer, it was established that RbP penetration into the cornea within 3 h of diffusion experiment was greater (17.3 ± 0.8 μg) compared with Rb (10.4 ± 4.2 μg). In the cornea, RbP was found to convert to Rb, which is mediated with enzymes present in this tissue. Several formulations including the conventional and propylene glycol-containing liposomes with encapsulated RbP have been developed, and their effect on the drug penetration into the bovine cornea was evaluated. Encapsulation of RbP into the liposomes did not provide any statistically significant improvement in the penetration of RbP into the cornea.
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Visible light-mediated photodegradation of imidazoline drugs in the presence of Riboflavin: Possible undesired effects on imidazoline-based eye drops. J Photochem Photobiol A Chem 2017. [DOI: 10.1016/j.jphotochem.2016.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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This issue at a glance. J Curr Ophthalmol 2016; 28:3-4. [PMID: 27239594 PMCID: PMC4881224 DOI: 10.1016/j.joco.2016.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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Assessment of a Novel Corneal-Shaping Device With Simultaneous Corneal Collagen Cross-Linking Using a Porcine Eye Model. Cornea 2016; 35:114-21. [PMID: 26509764 DOI: 10.1097/ico.0000000000000663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Corneal collagen cross-linking (CXL) alone cannot substantially improve refractive errors. We designed a novel corneal-shaping device, showing that a prototype applied during CXL can alter corneal curvature to a greater extent than CXL alone in a porcine eye model. METHODS The device prototype was made with flat, UV-transmissible material. Enucleated porcine eyes were deepithelialized and perfused. Preexperimental and postexperimental corneal curvature (K) measurements and Anterior Segment Optical Coherence Tomography imaging were performed. A conventional CXL protocol was followed. Six experiments of 6 treatment groups in duplicate were performed (n = 12/group): (A) no CXL + no device, (B) no CXL + 30 minutes device, (C) 10 minutes, CXL + no device, (D) 10 minutes, CXL + device, (E) 30 minutes, CXL + no device, and (F) 30 minutes, CXL + device. RESULTS There was a significant decrease (P < 0.001) in corneal curvature after 30 minutes. CXL between group F (-1.54 ± 0.90 D) and groups E (+0.34 ± 0.53 D), B (+0.69 ± 1.02 D), or A (+0.22 ± 1.24 D). The demarcation line depth was greater in group F (34% ± 4%) than group D (30% ± 4%, P < 0.05). Groups D (-2.3% ± 21%) and F (0.24% ± 15%) had less change in corneal thickness than in control groups A (15% ± 12%, P < 0.05) and E (12% ± 11%, P < 0.05). CONCLUSIONS Application of our corneal-shaping device during CXL significantly decreased corneal curvature compared with controls. Anterior Segment Optical Coherence Tomography imaging showed comparable extent of cross-linking in eyes treated ± device. This demonstrates that our novel device used during CXL may further promote corneal strengthening and refractive correction in patients.
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Hashemi H, Beiranvand A, Yekta A, Maleki A, Yazdani N, Khabazkhoob M. Pentacam top indices for diagnosing subclinical and definite keratoconus. J Curr Ophthalmol 2016; 28:21-6. [PMID: 27239598 PMCID: PMC4881219 DOI: 10.1016/j.joco.2016.01.009] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/26/2016] [Accepted: 01/26/2016] [Indexed: 11/17/2022] Open
Abstract
Purpose To determine pachymetric, aberrometric, and topometric indices in patients with definite and subclinical keratoconus and the validity of these indices in the diagnosis of keratoconus. Methods We evaluated 262 keratoconic and 97 healthy eyes in this study. Pentacam HR examination was performed for all participants, and the data of all pachymetric, aberrometric, and topometric indices was extracted for the study population. Results The average of all evaluated pachymetric and topometric indices and the 3rd and 5th order vertical coma aberrations showed a significant difference between the study groups (p < 0.001). Belin/Ambrosio Deviation Display (BAD_D), Index of Vertical Asymmetry (IVA), Index of Surface Variance (ISV), and 5th order vertical coma aberration were identified as the best diagnostic criteria for the diagnosis of subclinical keratoconus (R2 = 0.65, p <0.001), and BAD_D, mean keratometry and 3rd order vertical coma aberration were identified as the best diagnostic criteria for the diagnosis of definite keratoconus (R2 = 0.91, p <0.001). The sensitivity and specificity of the above-mentioned models were 83.6% and 96.9%, and 97.9% and 96.9%, respectively. Conclusion Simultaneous evaluation of BAD_D, 5th order vertical coma aberration, IVA, and ISV, especially when the pattern of the corneal curvature is normal, can detect subclinical keratoconus with high sensitivity and specificity. As for definite keratoconus, each of the BAD_D, mean keratometry, and 3rd order vertical coma aberration indices has a desirable diagnostic validity. However, the aforementioned indices do not negate the importance of widely recognized and acceptable indices like keratometry and central corneal thickness.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Asghar Beiranvand
- Health and nutrition Research Center, Lorestan University of Medical Sciences, Khoramabad, Iran
| | - Abbasali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Azam Maleki
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Negareh Yazdani
- Department of Epidemiology, Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Epidemiology, Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Nicholas DL, Gillian WD. Corneal cross-linking methods and outcomes: A review. AFRICAN VISION AND EYE HEALTH 2016. [DOI: 10.4102/aveh.v75i1.359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The prevalence of corneal ectasias such as keratoconus has been widely documented. Keratoconus may lead to detrimental changes in visual acuity, which can often be corrected in the early stages but requires more invasive treatment as the condition progresses. Corneal cross-linking has become a treatment method of choice in early keratoconic patients and is used to stabilise the condition and prevent further progression of the disease. The principle behind this procedure is the creation of additional bonds within the corneal structure in order to enhance its mechanical properties and thereafter halt the progression of the condition. There are disagreements within the literature as to how these procedures can be performed, and there are various alternative methods. It can be concluded that corneal cross-linking is an effective treatment method for keratoconus and has been shown to produce various beneficial effects in terms of ocular structure and function.
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Nita M, Grzybowski A. The Role of the Reactive Oxygen Species and Oxidative Stress in the Pathomechanism of the Age-Related Ocular Diseases and Other Pathologies of the Anterior and Posterior Eye Segments in Adults. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:3164734. [PMID: 26881021 PMCID: PMC4736974 DOI: 10.1155/2016/3164734] [Citation(s) in RCA: 845] [Impact Index Per Article: 105.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/16/2015] [Accepted: 11/17/2015] [Indexed: 12/18/2022]
Abstract
The reactive oxygen species (ROS) form under normal physiological conditions and may have both beneficial and harmful role. We search the literature and current knowledge in the aspect of ROS participation in the pathogenesis of anterior and posterior eye segment diseases in adults. ROS take part in the pathogenesis of keratoconus, Fuchs endothelial corneal dystrophy, and granular corneal dystrophy type 2, stimulating apoptosis of corneal cells. ROS play a role in the pathogenesis of glaucoma stimulating apoptotic and inflammatory pathways on the level of the trabecular meshwork and promoting retinal ganglion cells apoptosis and glial dysfunction in the posterior eye segment. ROS play a role in the pathogenesis of Leber's hereditary optic neuropathy and traumatic optic neuropathy. ROS induce apoptosis of human lens epithelial cells. ROS promote apoptosis of vascular and neuronal cells and stimulate inflammation and pathological angiogenesis in the course of diabetic retinopathy. ROS are associated with the pathophysiological parainflammation and autophagy process in the course of the age-related macular degeneration.
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Affiliation(s)
- Małgorzata Nita
- Domestic and Specialized Medicine Centre “Dilmed”, Ulica Bohaterów Monte Cassino 3, 40-231 Katowice, Poland
| | - Andrzej Grzybowski
- Department of Ophthalmology, Poznan City Hospital, Ulica Szwajcarska 3, 61-285 Poznań, Poland
- Chair of Ophthalmology, Medical Faculty, University of Warmia and Mazury, Ulica Żołnierska 14 C, 10-719 Olsztyn, Poland
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Semchishen A, Mrochen M, Semchishen V. Model for Optimization of the UV-A/Riboflavin Strengthening (cross-linking) of the Cornea: Percolation Threshold. Photochem Photobiol 2015; 91:1403-11. [DOI: 10.1111/php.12498] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/30/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Anton Semchishen
- Institute on Laser and Information Technologies of the Russian Academy of Sciences; Shatura Russia
| | - Michael Mrochen
- Institute for Refractive Ophthalmic Surgery - Eye Centre (IROC AG); Zurich Switzerland
| | - Vladimir Semchishen
- Institute on Laser and Information Technologies of the Russian Academy of Sciences; Shatura Russia
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Rate of corneal collagen crosslinking redo in private practice: risk factors and safety. J Ophthalmol 2015; 2015:690961. [PMID: 25874118 PMCID: PMC4383466 DOI: 10.1155/2015/690961] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 09/20/2014] [Accepted: 10/21/2014] [Indexed: 11/29/2022] Open
Abstract
Objective. To report the rate of progression of keratectasia after primary crosslinking (CXL) and evaluate the safety and efficiency of CXL redo. Materials and Methods. We conducted a retrospective analysis of the patients who underwent CXL between 2010 and 2013 at the Beirut Eye Specialist Hospital, Lebanon. Progression of keratectasia was based on the presence of an increase in maximum keratometry of 1.00 D, a change in the map difference between two consecutive topographies of 1.00 D, a deterioration of visual acuity, or any change in the refraction. Primary and redo CXL were done using the same protocol. Results. Among the 221 eyes of 130 patients who underwent CXL, 7 eyes (3.17%) of five patients met the criteria of progression. All patients reported a history of allergic conjunctivitis and eye rubbing and progressed within 9 to 48 months. No complications were noted and all patients were stable 1 year after CXL redo. Conclusion. Allergic conjunctivitis and eye rubbing were the only risk factors associated with keratoconus progression after CXL. A close followup is thus mandatory, even years after the procedure. CXL redo seems to be a safe and efficient technique to halt the progression after a primary CXL.
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Razmjoo H, Ghoreishi SM, Mohammadi Z, Salam H, Nasrollahi K, Peyman A. Comparison of the findings of endothelial specular microscopy before and after corneal cross-linking. Adv Biomed Res 2015; 4:52. [PMID: 25802821 PMCID: PMC4361966 DOI: 10.4103/2277-9175.151567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 08/31/2014] [Indexed: 11/05/2022] Open
Abstract
Background: To report the long-term findings of corneal cross-linking (CXL) with riboflavin drops on the corneal endothelial cell. Materials and Methods: In this prospective non-randomized study, we aim to assess the long-term safety of CXL on the corneal endothelium for the treatment of progressive keratoconus, by endothelial specular microscopy. A total of 68 eyes of 42 keratoconus patients were selected. We checked the corneal thickness (with ultrasonic pachymetry), endothelial cell density, pleomorphism, and polymegathism (with specular microscopy) of the endothelial cells, before CXL and one year after this procedure. Results: The mean ± SD of the preoperative and postoperative corneal thicknesses were 470 ± 40 μm and 469.8 ± 42 μm, respectively (p-value = 0.591). The mean ± SD of the preoperative and postoperative endothelial cell densities were 2753 ± 230 cells/mm[2] and 2699 ± 210 cells/mm,[2] respectively (p-value = 0.004). We found reduction in the endothelial cell density after CXL, but this reduction was less significant in a corneal thickness of less than 400 μm (which was treated with hypo-osmolar riboflavin 0.1% drops) compared to the corneal thickness of more than 450 μm. We did not find any significant differences in the cell shapes (pleomorphism) (p-value = 0.517), but the cell sizes (polymegathism) were changed after the procedure (p-value = 0.021). Conclusion: We found a significant decrease in endothelial corneal cell density after CXL, but this reduction was low; also the size of these cells increased after CXL. We believe that other parameters besides the corneal thickness may be the determinant factors for the changing of cell density and cell size in corneal endothelial cells.
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Affiliation(s)
- Hasan Razmjoo
- Department of Ophthalmology, Isfahan Eye Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Seyed Mohammad Ghoreishi
- Department of Ophthalmology, Isfahan Eye Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Zahra Mohammadi
- Department of Ophthalmology, Isfahan Eye Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hasan Salam
- Department of Ophthalmologist, Isfahan Eye Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Kobra Nasrollahi
- Department of Ophthalmology, Isfahan Eye Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Alireza Peyman
- Department of Ophthalmology, Isfahan Eye Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
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Long-term outcomes of intrastromal corneal ring segment implantation for post-LASIK ectasia. Cont Lens Anterior Eye 2014; 37:469-72. [DOI: 10.1016/j.clae.2014.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/08/2014] [Accepted: 07/21/2014] [Indexed: 11/17/2022]
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Nam K, Shimatsu Y, Matsushima R, Kimura T, Kishida A. In-situ polymerization of PMMA inside decellularized dermis using UV photopolymerization. Eur Polym J 2014. [DOI: 10.1016/j.eurpolymj.2014.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Theoretical basis, laboratory evidence, and clinical research of chemical surgery of the cornea: cross-linking. J Ophthalmol 2014; 2014:890823. [PMID: 25215226 PMCID: PMC4151584 DOI: 10.1155/2014/890823] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 11/18/2022] Open
Abstract
Corneal cross-linking (CXL) is increasingly performed in ophthalmology with high success rates for progressive keratoconus and other types of ectasia. Despite being an established procedure, some molecular and clinical aspects still require additional studies. This review presents a critical analysis of some established topics and others that are still controversial. In addition, this review examines new technologies and techniques (transepithelial and ultrafast CXL), uses of corneal CXL including natural products and biomolecules as CXL promoters, and evidence for in vitro and in vivo indirect effectiveness.
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Urs R, Lloyd HO, Silverman RH. Acoustic radiation force for noninvasive evaluation of corneal biomechanical changes induced by cross-linking therapy. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2014; 33:1417-26. [PMID: 25063407 PMCID: PMC4457329 DOI: 10.7863/ultra.33.8.1417] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
OBJECTIVES To noninvasively measure changes in corneal biomechanical properties induced by ultraviolet-activated riboflavin cross-linking therapy using acoustic radiation force (ARF). METHODS Cross-linking was performed on the right eyes of 6 rabbits, with the left eyes serving as controls. Acoustic radiation force was used to assess corneal stiffness before treatment and weekly for 4 weeks after treatment. Acoustic power levels were within US Food and Drug Administration guidelines for ophthalmic safety. Strain, determined from ARF-induced displacement of the front and back surfaces of the cornea, was fit to the Kelvin-Voigt model to determine the elastic modulus (E) and coefficient of viscosity (η). The stiffness factor, the ratio of E after treatment to E before treatment, was calculated for treated and control eyes. At the end of 4 weeks, ex vivo thermal shrinkage temperature analysis was performed for comparison with in vivo stiffness measurements. One-way analysis of variance and Student t tests were performed to test for differences in E, η, the stiffness factor, and corneal thickness. RESULTS Biomechanical stiffening was immediately evident in cross-linking-treated corneas. At 4 weeks after treatment, treated corneas were 1.3 times stiffer and showed significant changes in E (P= .006) and η (P= .007), with no significant effect in controls. Corneal thickness increased immediately after treatment but did not differ significantly from the pretreatment value at 4 weeks. CONCLUSIONS Our findings demonstrate a statistically significant increase in stiffness in cross-linking-treated rabbit corneas based on in vivo axial stress/strain measurements obtained using ARF. The capacity to noninvasively monitor corneal stiffness offers the potential for clinical monitoring of cross-linking therapy.
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Affiliation(s)
- Raksha Urs
- Department of Ophthalmology, Columbia University Medical Center, New York, New York USA (R.U., H.O.L., R.H.S.); and Frederic L. Lizzi Center for Biomedical Engineering, Riverside Research Institute, New York, New York USA (R.H.S.).
| | - Harriet O Lloyd
- Department of Ophthalmology, Columbia University Medical Center, New York, New York USA (R.U., H.O.L., R.H.S.); and Frederic L. Lizzi Center for Biomedical Engineering, Riverside Research Institute, New York, New York USA (R.H.S.)
| | - Ronald H Silverman
- Department of Ophthalmology, Columbia University Medical Center, New York, New York USA (R.U., H.O.L., R.H.S.); and Frederic L. Lizzi Center for Biomedical Engineering, Riverside Research Institute, New York, New York USA (R.H.S.)
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Ozgurhan EB, Celik U, Bozkurt E, Demirok A. Evaluation of subbasal nerve morphology and corneal sensation after accelerated corneal collagen cross-linking treatment on keratoconus. Curr Eye Res 2014; 40:484-9. [PMID: 24979260 DOI: 10.3109/02713683.2014.932387] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The aim of this study was to report on the evaluation of corneal nerve fiber density and corneal sensation after accelerated corneal collagen cross-linking on keratoconus patients. METHODS The study was performed on 30 keratoconus eyes (30 participants: 16 M, 14 F; 17-32 years old) treated with accelerated collagen cross-linking for disease stabilization. Mean outcome measures were corneal sensation evaluation by Cochet-Bonnet esthesiometry and subbasal nerve fiber density assessment by corneal in vivo confocal microscopy. All corneal measurements were performed using scanning slit confocal microscopy (ConfoScan 4, Nidek Technologies, Padova, Italy). RESULTS The accelerated corneal collagen cross-linking procedure was performed on 30 eyes of 30 patients (19 right, 63.3%; 11 left, 27.7%). The mean age was 23.93 ± 4. The preoperative mean keratometry, apex keratometry and pachymetry values were 47.19 ± 2.82 D, 56.79 ± 5.39 and 426.1 ± 25.6 μm, respectively. Preoperative mean corneal sensation was 56.3 ± 5.4 mm (with a range from 40 to 60 mm), it was significantly decreased at 1st and 3rd month visit and increased to preoperative values after 6th month visit. Preoperative mean of subbasal nerve fiber density measurements was 22.8 ± 9.7 nerve fiber/mm(2) (with a range of 5-45 mm), it was not still at the preoperative values at 6th month (p = 0.0001), however reached to the preoperative values at 12th month (p = 0.914). CONCLUSIONS Subbasal nerve fibers could reach the preoperative values at the 12th month after accelerated corneal collagen cross-linking treatment although the corneal sensation was improved at 6th month. These findings imply that the subjective healing process is faster than the objective evaluation of the keratoconus patients' cornea treated with accelerated corneal collagen cross-linking.
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Affiliation(s)
- Engin Bilge Ozgurhan
- Refractive Surgery, Beyoglu Eye Training and Research Hospital , Istanbul , Turkey and
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Yildirim A, Uslu H, Kara N, Cakir H, Gurler B, Colak HN, Ozgurhan EB. Same-day intrastromal corneal ring segment and collagen cross-linking for ectasia after laser in situ keratomileusis: long-term results. Am J Ophthalmol 2014; 157:1070-6. [PMID: 24513095 DOI: 10.1016/j.ajo.2014.02.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/30/2014] [Accepted: 02/03/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE To report the long-term results of combined same-day intrastromal corneal ring segment placement and corneal collagen cross-linking (CXL) for postoperative laser in situ keratomileusis (LASIK) ectasia. DESIGN Retrospective, interventional case series. METHOD This retrospective, interventional cases series was performed in Turkiye Hospital Eye Clinic and the Department of Ophthalmology, Fatih University Medical Faculty Hospital, Istanbul, Turkey. Sixteen eyes of 14 patients with postoperative ectasia after LASIK were enrolled. All consecutive patients were treated with femtosecond laser-assisted intrastromal corneal ring segment implantation and followed by same-day corneal collagen cross-linking for ectasia occurring after LASIK. Main outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, spherical and cylindrical refraction, and simulated keratometry values. RESULTS The mean age ± standard deviation of the 10 women and 4 men was 33.0 ± 6.5 years (range, 23 to 44 years), and the mean follow-up was 43 months (range, 36 to 62 months). The uncorrected distance visual acuity improved significantly from 1.18 ± 0.42 logarithm of the minimal angle of resolution (logMAR) units to 0.44 ± 0.22 logMAR (P < .001), and the corrected distance visual acuity improved significantly from 0.46 ± 0.26 logMAR to 0.21 ± 0.14 logMAR (P < .001). The mean spherical and cylindrical refraction decreased significantly (P < .001 for both). The maximum keratometry value decreased from baseline by 49.3 ± 4.9 diopters (D) to 43.9 ± 2.8 D at the last visit, and the minimum keratometry value decreased from 44.3 ± 4.7 D to 41.5 ± 3.5 D (P < .001 for both). No serious complications were shown during follow-up. CONCLUSIONS Implantation of intrastromal corneal ring segment implantation combined with same-day corneal collagen cross-linking was a safe and effective treatment for ectasia occurring after LASIK. It also significantly improved the visual acuity, refraction, and keratometry values.
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Abstract
PURPOSE To evaluate anterior and posterior changes in corneal topography and tomography after corneal crosslinking (CXL) in eyes with progressive keratoconus. METHODS Scheimpflug analyses (Pentacam, Oculus) of 20 eyes with keratoconus performed before and after corneal CXL were included into retrospective analysis. Mean follow-up was 2 years. Changes in topographic, tomographic, and pachymetric values were statistically analyzed applying analysis of variance. Further, the distance and direction between the anterior maximum keratometry (K(max)) and the apex as well as the distance and direction between the thinnest point in corneal thickness (TPCT) and the corneal apex before and after CXL were studied. RESULTS Two years after CXL, a statistically significant reduction of the keratometry at the flat meridian (-0.8 D, p < 0.05), the steep meridian (-0.5 D, p < 0.05), the "index of surface variance" (-5.3, p < 0.05), and the "index of highest decentration" (-0.05, p < 0.05) could be demonstrated. While the elevation of the front surface at the apex decreased (-1.5 μm, p < 0.05), the back elevation at the apex (+2 μm, p < 0.05) increased. Although not reaching statistical significance, the maximum front and back elevation demonstrated the same trend; while maximum front elevation data remained stable (-0.3 μm, p = 0.961), maximum back elevation data increased (+6.7 μm, p = 0.122). The corneal thickness at the apex (-22.0 μm, p < 0.001) and the TPCT (-20.0 μm, p < 0.001) decreased, leading to an increase of the corneal thickness progression from the corneal apex to the periphery. The position of K(max) and TPCT remained stable. CONCLUSIONS Corneal topography proved to be useful in the follow-up for CXL because of significant changes in the keratometry. Increasing posterior elevation values, despite a stabilized anterior corneal surface, might be a sign of ongoing ectatic changes in the posterior corneal surface.
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Beshtawi IM, Akhtar R, Hillarby MC, O’Donnell C, Zhao X, Brahma A, Carley F, Derby B, Radhakrishnan H. Biomechanical changes after repeated collagen cross-linking on human corneas assessed in vitro using scanning acoustic microscopy. Invest Ophthalmol Vis Sci 2014; 55:1549-54. [PMID: 24508795 PMCID: PMC4120094 DOI: 10.1167/iovs.13-13042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To explore the biomechanical changes induced by repeated cross-linking using scanning acoustic microscopy (SAM). METHODS Thirty human corneas were divided into three groups. In group A, five corneas were cross-linked once. In group B, five corneas were cross-linked twice, 24 hours apart. In group C, five corneas were cross-linked three times, 24 hours apart. The contralateral controls in all groups had similar treatment but without UV-A. The speed of sound, which is directly proportional to the square root of the tissue's elastic modulus, was assessed using SAM. RESULTS In group A, the speed of sound of the treated corneas was 1677.38 ± 10.70 ms(-1) anteriorly and 1603.90 ± 9.82 ms(-1) posteriorly, while it was 1595.23 ± 9.66 ms(-1) anteriorly and 1577.13 ± 8.16 ms(-1) posteriorly in the controls. In group B, the speed of sound of the treated corneas was 1746.33 ± 23.37 ms(-1) anteriorly and 1631.60 ± 18.92 ms(-1) posteriorly, while it was 1637.57 ± 22.15 ms(-1) anteriorly and 1612.30 ± 22.23 ms(-1) posteriorly in the controls. In group C, the speed of sound of the treated corneas was 1717.97 ± 18.92 ms(-1) anteriorly and 1616.62 ± 17.58 ms(-1) posteriorly, while it was 1628.69 ± 9.37 ms(-1) anteriorly and 1597.68 ± 11.97 ms(-1) posteriorly in the controls. The speed of sound in the anterior (200 × 200 μm) region between the cross-linked and control corneas in groups A, B, and C was increased by a factor of 1.051 (P = 0.005), 1.066 (P = 0.010), and 1.055 (P = 0.005) respectively. However, there was no significant difference among the cross-linked corneas in all groups (P = 0.067). CONCLUSIONS A significant increase in speed of sound was found in all treated groups compared with the control group; however, the difference among the treated groups is not significant, suggesting no further cross-links are induced when collagen cross-linking treatment is repeated.
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Affiliation(s)
- Ithar M. Beshtawi
- Optometry Department, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Riaz Akhtar
- Centre for Materials and Structures, School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - M. Chantal Hillarby
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, The University of Manchester, Manchester, United Kingdom
| | | | - Xuegen Zhao
- Manchester Materials Science Centre, School of Materials, The University of Manchester, Manchester, United Kingdom
| | - Arun Brahma
- Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester
| | - Fiona Carley
- Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester
| | - Brian Derby
- Manchester Materials Science Centre, School of Materials, The University of Manchester, Manchester, United Kingdom
| | - Hema Radhakrishnan
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
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Babczyk P, Conzendorf C, Klose J, Schulze M, Harre K, Tobiasch E. Stem Cells on Biomaterials for Synthetic Grafts to Promote Vascular Healing. J Clin Med 2014; 3:39-87. [PMID: 26237251 PMCID: PMC4449663 DOI: 10.3390/jcm3010039] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 10/28/2013] [Accepted: 11/16/2013] [Indexed: 12/25/2022] Open
Abstract
This review is divided into two interconnected parts, namely a biological and a chemical one. The focus of the first part is on the biological background for constructing tissue-engineered vascular grafts to promote vascular healing. Various cell types, such as embryonic, mesenchymal and induced pluripotent stem cells, progenitor cells and endothelial- and smooth muscle cells will be discussed with respect to their specific markers. The in vitro and in vivo models and their potential to treat vascular diseases are also introduced. The chemical part focuses on strategies using either artificial or natural polymers for scaffold fabrication, including decellularized cardiovascular tissue. An overview will be given on scaffold fabrication including conventional methods and nanotechnologies. Special attention is given to 3D network formation via different chemical and physical cross-linking methods. In particular, electron beam treatment is introduced as a method to combine 3D network formation and surface modification. The review includes recently published scientific data and patents which have been registered within the last decade.
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Affiliation(s)
- Patrick Babczyk
- Department of Natural Science, Bonn-Rhein-Sieg University of Applied Science, Von-Liebig-Street 20, Rheinbach 53359, Germany.
| | - Clelia Conzendorf
- Faculty of Mechanical Engineering/Process Engineering, University of Applied Science Dresden, Friedrich-List-Platz 1, Dresden 01069, Germany.
| | - Jens Klose
- Faculty of Mechanical Engineering/Process Engineering, University of Applied Science Dresden, Friedrich-List-Platz 1, Dresden 01069, Germany.
| | - Margit Schulze
- Department of Natural Science, Bonn-Rhein-Sieg University of Applied Science, Von-Liebig-Street 20, Rheinbach 53359, Germany.
| | - Kathrin Harre
- Faculty of Mechanical Engineering/Process Engineering, University of Applied Science Dresden, Friedrich-List-Platz 1, Dresden 01069, Germany.
| | - Edda Tobiasch
- Department of Natural Science, Bonn-Rhein-Sieg University of Applied Science, Von-Liebig-Street 20, Rheinbach 53359, Germany.
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Wu W, Wang Y, Xu L. Meta-analysis of Pentacam vs. ultrasound pachymetry in central corneal thickness measurement in normal, post-LASIK or PRK, and keratoconic or keratoconus-suspect eyes. Graefes Arch Clin Exp Ophthalmol 2013; 252:91-9. [PMID: 24218039 DOI: 10.1007/s00417-013-2502-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/08/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND The aim of this meta-analysis is to evaluate the central corneal thickness (CCT) measurement differences between Pentacam (Oculus Inc., Germany) and Ultrasound Pachymetry (USP) in normal (unoperated eyes , myopic and astigmatic eyes without corneal disease or topographic irregularity), after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), and keratoconic or keratoconus suspected eyes. We assess whether Pentacam and USP have similar CCT differences in normal, thinner corneas after LASIK or PRK procedures, and kerotoconic or keratoconus suspected eyes. METHODS Data sources, including PubMed, Medline, EMBASE, and Cochrane Central Registry of Controlled Trials on the Cochrane Library, were searched to find the relevant studies. Primary outcome measures were CCT measurement between Pentacam and USP. Three groups of eyes were analyzed: normal; LASIK or PRK eyes; and keratoconus suspected or keratoconic eyes. RESULTS Nineteen studies describing 1,908 eyes were enrolled in the normal group. Pentacam results were 1.47 μm ,95 % confidence interval (CI) -2.32 to 5.27, higher than USP without statistically significant difference (P = 0.45). Nine studies with total 539 eyes were included in the corneas after LASIK or PRK. The mean difference in the CCT measurement with Pentacam and ultrasound pachymetry was 1.03 μm, with the 95 % CI -3.36 to 5.42, there was no statistically difference (P = 0.64). Four studies with a total of 185 eyes were included in the keratoconic eyes or keratoconus-suspect group, however,the mean difference was -6.33 μm (95 % CI -9.17 to-3.49), which was statistically different between Pentacam and ultrasound pachymetry in the CCT measurement (P < 0.0001). CONCLUSIONS Pentacam offers similar CCT results to ultrasound pachymetry in normal eyes, thinner corneas after LASIK or PRK procedures. However, in keratoconic or keratoconus-suspect eyes, Pentacam slightly underestimates the central corneal thickness than does ultrasound pachymetry, which may result from the difficulty in fixation of keratoconic eyes, misalignment of Pentacam and the variation of ultrasonic velocity due to the histological deformation.
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Affiliation(s)
- Wenjing Wu
- Tianjin Eye Hospital& Eye Institute, Tianjin Ophthalmology and Visual Science Key Laboratory, Clinical College of Ophthalmology, Tianjin Medical University, No 4. Gansu Rd, Heping District, Tianjin, 300020, China
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McGrath LA, Lee GA. Corneal Debridement Update: Adjuvant Therapies and Wound Healing. Asia Pac J Ophthalmol (Phila) 2013; 2:237-43. [PMID: 26106918 DOI: 10.1097/apo.0b013e31829e69b0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Corneal debridement techniques have seen evolution in instrumentation and indication. Although the techniques themselves are simple and usually effective, there is often the need for adjuvant topical therapies to augment healing and/or prevent recurrence of disease. To better understand the requirement for adjuvant therapies, the current theories of corneal wound healing are reviewed.
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Affiliation(s)
- Lindsay A McGrath
- From the *City Eye Centre; †University of Queensland; and ‡Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
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Kanellopoulos AJ, Asimellis G. Introduction of quantitative and qualitative cornea optical coherence tomography findings induced by collagen cross-linking for keratoconus: a novel effect measurement benchmark. Clin Ophthalmol 2013; 7:329-35. [PMID: 23440024 PMCID: PMC3577010 DOI: 10.2147/opth.s40455] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose To introduce a novel, noninvasive technique to determine the depth and extent of anterior corneal stroma changes induced by collagen cross-linking (CXL) using quantitative analysis of high-resolution anterior-segment optical coherence tomography (OCT) post-operative images. Setting Private clinical ophthalmology practice. Patients and methods Two groups of corneal cross-sectional images obtained with the OptoVue RTVue anterior-segment OCT system were studied: group A (control) consisted of unoperated, healthy corneas, with the exception of possible refractive errors. The second group consisted of keratoconic corneas with CXL that were previously operated on. The two groups were investigated for possible quantitative evidence of changes induced by the CXL, and specifically, the depth, horizontal extent, as well as the cross-sectional area of intrastromal hyper-reflective areas (defined in our study as the area consisting of pixels with luminosity greater than the mean +2 × standard deviation of the entire stromal cross section) within the corneal stroma. Results In all images of the second group (keratoconus patients treated with CXL) there was evidence of intrastromal hyper-reflective areas. The hyper-reflective areas ranged from 0.2% to 8.8% of the cross-sectional area (mean ± standard deviation; 3.46% ± 1.92%). The extent of the horizontal hyper-reflective area ranged from 4.42% to 99.2% (56.2% ± 23.35%) of the cornea image, while the axial extent (the vertical extent in the image) ranged from 40.00% to 86.67% (70.98% ± 7.85%). There was significant statistical difference (P < 0.02) in these values compared to the control group, in which, by application of the same criteria, the same hyper-reflective area (owing to signal noise) ranged from 0.00% to 2.51% (0.74% ± 0.63%). Conclusion Herein, we introduce a novel, noninvasive, quantitative technique utilizing anterior segment OCT images to quantitatively assess the depth and cross-sectional area of CXL in the corneal stroma based on digital image analysis. Mean cross-sectional area showing evidence of CXL was 3.46% ± 1.92% of a 6 mm long segment.
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Affiliation(s)
- A John Kanellopoulos
- Laservision.gr Institute, Athens, Greece ; New York University Medical School, New York, NY, USA
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Edmonds JN, Moshirfar M. LASIK and Surface Ablation in the Modern Era: Trends and Novel Applications. CURRENT OPHTHALMOLOGY REPORTS 2013. [DOI: 10.1007/s40135-012-0004-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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