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Raiskup F, Herber R, Lenk J, Pillunat LE, Spoerl E. Crosslinking with UV-A and riboflavin in progressive keratoconus: From laboratory to clinical practice - Developments over 25 years. Prog Retin Eye Res 2024; 102:101276. [PMID: 38830532 DOI: 10.1016/j.preteyeres.2024.101276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024]
Abstract
Changes in the biomechanical and biochemical properties of the human cornea play an important role in the pathogenesis of ectatic diseases. A number of conditions in primarily acquired (keratoconus or pellucid marginal degeneration) or secondarily induced (iatrogenic keratectasia after refractive laser surgeries) ectatic disorders lead to decreased biomechanical stability. Corneal collagen cross-linking (CXL) represents a technique to slow or even halt the progression of ectatic pathologies. In this procedure, riboflavin is applied in combination with ultraviolet A radiation. This interaction induces the production of reactive oxygen species, which leads to the formation of additional covalent bonds between collagen molecules and subsequent biomechanical corneal strengthening. This procedure is so far the only method that partially interferes etiopathogenetically in the treatment of ectatic diseases that slows or stops the process of corneal destabilization, otherwise leading to the need for corneal transplantation. Besides, CXL process increases markedly resistance of collagenous matrix against digesting enzymes supporting its use in the treatment of corneal ulcers. Since the discovery of this therapeutic procedure and the first laboratory experiments, which confirmed the validity of this method, and the first clinical studies that proved the effectiveness and safety of the technique, it has been spread and adopted worldwide, even with further modifications. Making use of the Bunsen-Roscoe photochemical law it was possible to shorten the duration of this procedure in accelerated CXL and thus improve the clinical workflow and patient compliance while maintaining the efficacy and safety of the procedure. The indication spectrum of CXL can be further expanded by combining it with other vision-enhancing procedures such as individualized topographically-guided excimer ablation. Complementing both techniques will allow a patient with a biomechanically stable cornea to regularize it and improve visual acuity without the need for tissue transplantation, leading to a long-term improvement in quality of life.
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Affiliation(s)
- Frederik Raiskup
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
| | - Robert Herber
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Janine Lenk
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Lutz E Pillunat
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Eberhard Spoerl
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
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Higa K, Kimoto R, Kojima T, Dogru M, Müller-Lierheim WGK, Shimazaki J. Therapeutic Aqueous Humor Concentrations of Latanoprost Attained in Rats by Administration in a Very-High-Molecular-Weight Hyaluronic Acid Eye Drop. Pharmaceutics 2024; 16:523. [PMID: 38675184 PMCID: PMC11053993 DOI: 10.3390/pharmaceutics16040523] [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: 01/22/2024] [Revised: 03/25/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
The temporal change in concentration of a novel medicine, Latanoprost (LP), was evaluated in the aqueous humor of rats (6-8-week-old Jcl:Wister rats) when delivered in a very-high-molecular-weight hyaluronic acid (vHiHA) eye drop. Animals were randomly assigned to three treatment groups (LP + vHiHA (LPvHiHA), commercial LP (cLP), and diluted LP (dLP)) and after instilling the eye drops, the aqueous humor (AH) was collected at 0.5, 1, 2, 4, and 6 h to measure the LP concentration using an enzyme-linked immunosorbent assay (ELISA). Although the LP concentration in the LPvHiHA eye drop formulation was 3.57 times lower than in the commercial eye drops used (cLP), the LP concentration in the AH following LPvHiHA administration reached a value close to that of cLP. The cLP was diluted to the same concentration of LP as in the LPvHiHA eye drops for the dLP group, but the LP concentration in the AH of these animals was lower than that of the LPvHiHA rats at all time points. The higher LP concentration in the AH of the LPvHiHA rats suggests that vHiHA may aid the transport of LP across the ocular surface epithelium.
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Affiliation(s)
- Kazunari Higa
- Cornea Center Eye Bank, Tokyo Dental College Ichikawa General Hospital, 5-11-13 Sugano, Ichikawa 272-8513, Japan; (R.K.); (J.S.)
| | - Reona Kimoto
- Cornea Center Eye Bank, Tokyo Dental College Ichikawa General Hospital, 5-11-13 Sugano, Ichikawa 272-8513, Japan; (R.K.); (J.S.)
| | - Takashi Kojima
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Tokyo 160-8582, Japan; (T.K.); (M.D.)
| | - Murat Dogru
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Tokyo 160-8582, Japan; (T.K.); (M.D.)
| | | | - Jun Shimazaki
- Cornea Center Eye Bank, Tokyo Dental College Ichikawa General Hospital, 5-11-13 Sugano, Ichikawa 272-8513, Japan; (R.K.); (J.S.)
- Department of Ophthalmology, Tokyo Dental College Ichikawa General Hospital, 5-11-13 Sugano, Ichikawa 272-8513, Japan
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Lombardo M, Serrao S, Bernava GM, Mencucci R, Fruschelli M, Lombardo G. Real-time monitoring of riboflavin concentration using different clinically available ophthalmic formulations for epi-off and epi-on corneal cross-linking. Graefes Arch Clin Exp Ophthalmol 2024:10.1007/s00417-024-06451-8. [PMID: 38502352 DOI: 10.1007/s00417-024-06451-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/27/2024] [Accepted: 03/08/2024] [Indexed: 03/21/2024] Open
Abstract
PURPOSE To assess the feasibility of theranostics to determine the riboflavin concentration in the cornea using clinically available ophthalmic formulations during epithelium-off (epi-off) and transepithelial (epi-on) corneal cross-linking procedures. METHODS Thirty-two eye bank human donor corneas were equally randomized in eight groups; groups 1 to 3 and groups 4 to 8 underwent epi-off and epi-on delivery of riboflavin respectively. Riboflavin ophthalmic solutions were applied onto the cornea according to the manufacturers' instructions. The amount of riboflavin into the cornea was estimated, at preset time intervals during imbibition time, using theranostic UV-A device (C4V CHROMO4VIS, Regensight srl, Italy) and expressed as riboflavin score (d.u.). Measurements of corneal riboflavin concentration (expressed as µg/cm3) were also performed by spectroscopy absorbance technique (AvaLight-DH-S-BAL, Avantes) for external validation of theranostic measurements. RESULTS At the end of imbibition time in epi-off delivery protocols, the average riboflavin score ranged from 0.77 ± 0.38 (the average corneal riboflavin concentration was 213 ± 190 µg/cm3) to 1.79 ± 0.07 (554 ± 103 µg/cm3). In epi-on delivery protocols, the average riboflavin score ranged from 0.17 ± 0.01 to 0.67 ± 0.19 (corneal riboflavin concentration ranged from 6 ± 5 µg/cm3 to 122 ± 39 µg/cm3) at the end of imbibition time. A statistically significant linear correlation (P ≤ 0.05) was found between the theranostic and spectrophotometry measurements in all groups. CONCLUSIONS Real-time theranostic imaging provided an accurate strategy for assessing permeation of riboflavin into the human cornea during the imbibition phase of corneal cross-linking, regardless of delivery protocol. A large variability in corneal riboflavin concentration exists between clinically available ophthalmic formulations both in epi-off and epi-on delivery protocols.
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Affiliation(s)
- Marco Lombardo
- Studio Italiano di Oftalmologia, Via Livenza 3, 00198, Rome, Italy.
- Vision Engineering Italy Srl, Via Livenza 3, 00198, Rome, Italy.
| | - Sebastiano Serrao
- Studio Italiano di Oftalmologia, Via Livenza 3, 00198, Rome, Italy
- Vision Engineering Italy Srl, Via Livenza 3, 00198, Rome, Italy
| | - Giuseppe Massimo Bernava
- CNR-IPCF, Istituto per i Processi Chimico-Fisici, Viale F. Stagno D'Alcontres 37, 98158, Messina, Italy
| | - Rita Mencucci
- SOD Oculistica, AOU Careggi, Università di Firenze, Largo Brambilla 3, 50134, Florence, Italy
| | - Mario Fruschelli
- Sezione Oftalmologia, Policlinico Santa Maria alle Scotte, Università di Siena, Dip. Scienze mediche-chirurgiche e neuroscienze, Viale Bracci, 53100, Siena, Italy
| | - Giuseppe Lombardo
- Studio Italiano di Oftalmologia, Via Livenza 3, 00198, Rome, Italy.
- CNR-IPCF, Istituto per i Processi Chimico-Fisici, Viale F. Stagno D'Alcontres 37, 98158, Messina, Italy.
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Cronin B, Gunn D, Chang CY. Oxygen-supplemented and topography-guided epithelium-on corneal crosslinking with pulsed irradiation for progressive keratoconus. J Cataract Refract Surg 2024; 50:209-216. [PMID: 38381615 PMCID: PMC10878465 DOI: 10.1097/j.jcrs.0000000000001339] [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: 04/27/2023] [Revised: 10/05/2023] [Accepted: 10/08/2023] [Indexed: 02/23/2024]
Abstract
PURPOSE To investigate the effects of customized topography-guided epithelium-on crosslinking (epi-on CXL) with oxygen supplementation on procedural efficacy and corrected distance visual acuity (CDVA) in patients with progressive keratoconus (KC) at 1 year. SETTING Private eye clinic, Brisbane, Australia. DESIGN Retrospective, single-center, nonrandomized case series. METHODS Topography-guided epi-on CXL using the Mosaic system was performed on patients with progressive KC. Oxygen goggles; transepithelial riboflavin; and pulsed, high UV-A irradiance (1 second on, 1 second off; 30 mW/cm2) were applied to enhance oxygen kinetics and bioavailabilities of riboflavin and UV-A. Guided by baseline topography, a higher UV-A dose (15 J/cm2) was applied to the area of steepest anterior curvature with decreasing fluence (as low as 7.2 J/cm2) toward the outer 9 mm. Postoperative CDVA and maximum keratometry (Kmax) were evaluated. RESULTS 102 eyes (80 patients) were followed for 11.5 ± 4.8 months. At the latest follow-up, mean CDVA (logMAR), mean K, and Kmax (diopters [D]) improved from 0.18 ± 0.28, 46.2 ± 3.8, and 53.0 ± 5.67 at baseline to 0.07 ± 0.18, 45.8 ± 3.7, and 51.9 ± 5.56, respectively (P < .001). 3 eyes (3%) lost more than 1 CDVA line, and another 3 eyes (3%) had increased Kmax greater than 2 D. 43 eyes were followed for at least 12 months (n = 43): mean CDVA, mean K, and Kmax improved from 0.19 ± 0.33 logMAR, 46.5 ± 3.5 D, and 53.6 ± 5.67 D to 0.07 ± 0.17 logMAR, 46.0 ± 3.5 D, and 52.33 ± 5.49 D, respectively (P ≤ .002). No complications were observed. CONCLUSIONS Tailoring oxygen-supplemented epi-on CXL with differential UV-A energy distributions, guided by baseline topography, in patients with KC seems to be safe and effective. At 1 year, study reports sustained improved CDVA and corneal stabilization.
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Affiliation(s)
- Brendan Cronin
- From the Queensland Eye Institute, Brisbane, Queensland, Australia (Cronin, Gunn); Medical Affairs, Burlington, Massachusetts (Chang); Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania (Chang)
| | - David Gunn
- From the Queensland Eye Institute, Brisbane, Queensland, Australia (Cronin, Gunn); Medical Affairs, Burlington, Massachusetts (Chang); Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania (Chang)
| | - Clark Y. Chang
- From the Queensland Eye Institute, Brisbane, Queensland, Australia (Cronin, Gunn); Medical Affairs, Burlington, Massachusetts (Chang); Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania (Chang)
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Qin D, Han Y, Wang L, Yin H. Recent advances in medicinal compounds related to corneal crosslinking. Front Pharmacol 2023; 14:1232591. [PMID: 37841929 PMCID: PMC10570464 DOI: 10.3389/fphar.2023.1232591] [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] [Received: 05/31/2023] [Accepted: 09/21/2023] [Indexed: 10/17/2023] Open
Abstract
Corneal crosslinking (CXL) is the recognized technique to strengthen corneal collagen fibers through photodynamic reaction, aiming to halt progressive and irregular changes in corneal shape. CXL has greatly changed the treatment for keratoconus (KCN) since it was introduced in the late 1990's. Numerous improvements of CXL have been made during its developing course of more than 20 years. CXL involves quite a lot of materials, including crosslinking agents, enhancers, and supplements. A general summary of existing common crosslinking agents, enhancers, and supplements helps give a more comprehensive picture of CXL. Either innovative use of existing materials or research and development of new materials will further improve the safety, effectiveness, stability, and general applicability of CXL, and finally benefit the patients.
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Affiliation(s)
- Danyi Qin
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute and Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yi Han
- Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Eye Institute and Affiliated Xiamen Eye Center, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Lixiang Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Hongbo Yin
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
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Lombardo M, Bernava GM, Serrao S, Roszkowska AM, Lombardo G. Predicting corneal cross-linking treatment efficacy with real-time assessment of corneal riboflavin concentration. J Cataract Refract Surg 2023; 49:635-641. [PMID: 36745847 DOI: 10.1097/j.jcrs.0000000000001163] [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: 09/28/2022] [Accepted: 01/30/2023] [Indexed: 02/08/2023]
Abstract
PURPOSE To assess predictability of tissue biomechanical stiffening induced by UV-A light-mediated real-time assessment of riboflavin concentration during corneal crosslinking (CXL) of human donor tissues. SETTING Studio Italiano di Oftalmologia, Rome, Italy. DESIGN Laboratory study. METHODS 20 sclerocorneal tissues were randomly stratified to undergo CXL with either the epithelium intact (n = 12) or removed (n = 8). Samples underwent corneal soaking with 0.22% riboflavin formulation (RitSight) with dosing time of t = 10 minutes and t = 20 minutes in epithelium-off and epithelium-on protocols, respectively. All tissues underwent 9-minute UV-A irradiance at 10 mW/cm 2 using theranostic device (C4V CHROMO4VIS). The device used controlled UV-A light irradiation to induce both imaging and treatment of the cornea, providing a real-time measure of corneal riboflavin concentration and treatment efficacy (ie, theranostic score) during surgery. Tissue biomechanics were assessed with an air-puff device (Corvis), which was performed before and after treatment. A 3-element viscoelastic model was developed to fit the corneal deformation response to air-puff excitation and to calculate the mean corneal stiffness parameter (k c ). RESULTS Significant corneal tissue stiffening ( P < .05) was induced by the theranostic UV-A device in either CXL treatment protocol. Significant correlation was found between the theranostic score and the increase in k c ( R = 0.75; P = .003). The score showed high accuracy (94%) and precision (94%) to predict correctly samples that had improved tissue biomechanical strengthening. CONCLUSIONS Real-time assessment of corneal riboflavin concentration provided a predictive and precise approach for significant improvement of tissue strength on individual corneas, regardless of CXL treatment protocol.
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Affiliation(s)
- Marco Lombardo
- From the Studio Italiano di Oftalmologia, Rome, Italy (M. Lombardo, Serrao, G. Lombardo); Vision Engineering Italy srl, Rome, Italy (M. Lombardo); CNR-IPCF, Istituto per i Processi Chimico-Fisici, Messina, Italy (Bernava, G. Lombardo); Clinica Oculistica, Dipartimento di Scienze Biomediche, Università degli Studi di Messina, Messina, Italy (Roszkowska); Ophthalmology Department, Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski Krakow University, Poland (Roszkowska)
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Aribas YK, Tefon Aribas AB, Ercin U, Sarıkaya B, Bilgihan A, Bilgihan K. Iontophoresis Corneal Cross-linking With Oxygen Supplementation in Ovine Eyes. J Refract Surg 2022; 38:674-681. [DOI: 10.3928/1081597x-20220906-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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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: 0] [Impact Index Per Article: 0] [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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Hafezi F. Corneal Cross-Linking: Epi-On. Cornea 2022; 41:1203-1204. [DOI: 10.1097/ico.0000000000003075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/17/2022] [Indexed: 11/25/2022]
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Beckman KA. Epithelium-on Corneal Collagen Cross-Linking with Hypotonic Riboflavin Solution in Progressive Keratoconus. Clin Ophthalmol 2021; 15:2921-2932. [PMID: 34262252 PMCID: PMC8273905 DOI: 10.2147/opth.s318317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/09/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction Epithelium-off cross-linking (epi-off CXL) has long been established as the gold standard treatment for progressive keratoconus. Several protocols for epithelium-on (epi-on) CXL have been proposed to help reduce post-operative pain and facilitate visual recovery, but there is no epi-on treatment approach that is currently approved in the United States. The hydrophilic and macromolecular characteristics of conventional epi-off riboflavin formulations may create clinical challenges for absorption through an intact epithelium. This study investigates the clinical efficacy of a dextran-free hypotonic riboflavin ophthalmic solution (Photrexa, Glaukos, Burlington, MA, USA), approved for epi-off CXL, in a novel epi-on CXL protocol. Methods Twenty-five eyes of 17 patients were treated in this prospective, single-arm study using a hypotonic riboflavin formulation without dextran and low irradiance UVA (3mW/cm2) for epi-on CXL. Visual acuity, as well as refractive and keratometry outcomes, were observed over 12 months. Results At 12 months, Kmax was stable with no clinically or statistically significant change from a mean pre-op of 55.4D to 55.9D (p=0.13). Uncorrected and best corrected logMAR visual acuity significantly improved from 0.77 to 0.62 and from 0.17 to 0.12, respectively. There were no significant adverse safety events. Conclusion Patients who underwent epi-on CXL with dextran-free hypotonic riboflavin demonstrated improvements in uncorrected and best corrected visual acuity with stable keratometry at 12 months post-operatively. The efficacy is consistent with other epi-on studies to date but remains lower than standard epi-off CXL. New technologies, including supplemental oxygen and transepithelial riboflavin ophthalmic solutions, are currently under clinical evaluation and may offer a path forward for epi-on CXL in the USA.
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Affiliation(s)
- Kenneth A Beckman
- Comprehensive EyeCare of Central Ohio, Westerville, OH, USA.,The Ohio State University, Columbus, OH, USA
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Alkayid H, Asena L, Yüce A, Yavuz Çolak M, Altınörs DD. Comparison of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in keratoconus treatment. Ther Adv Ophthalmol 2021; 13:25158414211020147. [PMID: 34250443 PMCID: PMC8239960 DOI: 10.1177/25158414211020147] [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: 03/30/2020] [Accepted: 05/06/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose To compare the severity and duration of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in the treatment of keratoconus. Methods Fifty-five patients (65 eyes) known to have keratoconus were enrolled in this retrospective study. The eyes were divided into three groups based on the technique used for epithelial debridement for corneal collagen cross-linking procedure; excimer laser transepithelial phototherapeutic keratectomy was used in group 1 (18 eyes), alcohol-assisted epithelial removal was used in group 2 (27 eyes), and mechanical epithelial debridement was used in group 3 (20 eyes). Preoperative and postoperative (third month) best-corrected visual acuity (BCVA) using Snellen chart, objective refraction, and keratometry results were recorded. The results of the questionnaire obtained from the patient's medical records were reviewed regarding their subjective evaluation of postoperative symptoms including foreign body sensation, tearing, photophobia, and burning at the end of the first postoperative week. Paired-samples t test was used to compare preoperative and postoperative clinical findings. One-way analysis of variance (ANOVA) was used to analyze the differences between three independent groups. Results BCVA improved from 0.51 ± 0.27 to 0.58 ± 0.21 (p = 0.05). Objective mean spherical and cylindrical refraction decreased from -5.08 ± 2.78D to -4.46 ± 2.91D (p = 0.22) and from -3.45 ± 2.73D to -3.03 ± 1.97D (p = 0.25). Mean maximum keratometry reading (K max) decreased from 57.63 ± 4.73D to 56.13 ± 4.47D (p = 0.001). The mean score for foreign body sensation was the highest in group 3 (4.50 ± 0.53) and the lowest in group 1 (2.10 ± 1.85) (p = 0.01). The mean scores for tearing, photophobia, and burning sensation were comparable in three groups (p = 0.84, p = 0.13, and p = 0.61, respectively). The duration of photophobia was the shortest in group 1 (1.50 ± 2.37 days), followed by group 3 (2.00 ± 1.31 days) and group 2 (4.00 ± 1.83 days) (p = 0.04). Conclusions The severity and duration of adverse subjective symptoms during the first postoperative week after corneal collagen cross-linking appear to be milder with epithelial debridement using excimer laser transepithelial technique compared with -assisted debridement and mechanical debridement.
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Affiliation(s)
- Hosamadden Alkayid
- Jordanian Royal Medical Services, King Hussein Medical Center, Amman, Jordan
| | - Leyla Asena
- Department of Ophthalmology, Faculty of Medicine, Başkent University, Ankara, Turkey
| | - Aslihan Yüce
- Department of Ophthalmology, Faculty of Medicine, Başkent University, Ankara, Turkey
| | - Meriç Yavuz Çolak
- Department of Ophthalmology, Faculty of Medicine, Başkent University, Ankara, Turkey
| | - Dilek Dursun Altınörs
- Department of Ophthalmology, Faculty of Medicine, Başkent University, Ankara, Turkey
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Lang SJ, Maier P, Reinhard T. Crosslinking und Keratokonus. AUGENHEILKUNDE UP2DATE 2021. [DOI: 10.1055/a-1205-7737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
ZusammenfassungEin Keratokonus führt zu einer progressiven Vorwölbung und Verdünnung der
Hornhaut. Um dies aufzuhalten, kann ein Crosslinking durchgeführt werden. Dabei
ist eine Behandlung nach dem „Dresdener Protokoll“ eine effektive und sichere
Behandlungsmöglichkeit, aber auch zahlreiche neue Anwendungsprotokolle
(akzeleriertes Crosslinking, transepitheliales Crosslinking) und sogar weitere
Indikationen (refraktive Eingriffe, infektiöse Keratitis) wurden in den letzten
Jahren veröffentlicht.
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Lang SJ, Maier P, Reinhard T. [Crosslinking and Keratoconus]. Klin Monbl Augenheilkd 2021; 238:733-747. [PMID: 33873207 DOI: 10.1055/a-1472-0411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Keratoconus leads to a progressive protrusion and thinning of the cornea. In order to stop this, corneal crosslinking can be performed if the progression of the disease is proven. Crosslinking according to the "Dresden protocol" includes abrasion of the corneal epithelium, application of riboflavin eye drops and irradiation with UV-A light of an intensity of 3 mW/cm² for 30 minutes. The efficacy has been shown in several prospective randomized studies. One of the more recent developments is accelerated crosslinking, which allows a shorter irradiation time. On the other hand, the possibility of transepithelial crosslinking was presented, which does not require an abrasion of the cornea. This should reduce the occurrence of postoperative pain. The range of indications has also been expanded. Corneal crosslinking is used for post-LASIK keratectasia as well. It is also being considered for use in infectious keratitis. Topographically controlled crosslinking can likewise be used to try to positively influence the refractive power of the cornea. The risks of crosslinking include the occurrence of pain, haze or scarring, endothelial cell damage and, rarely, the occurrence of keratitis.
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Hill J, Liu C, Deardorff P, Tavakol B, Eddington W, Thompson V, Gore D, Raizman M, Adler DC. Optimization of Oxygen Dynamics, UV-A Delivery, and Drug Formulation for Accelerated Epi-On Corneal Crosslinking. Curr Eye Res 2019; 45:450-458. [PMID: 31532699 DOI: 10.1080/02713683.2019.1669663] [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: 02/08/2023]
Abstract
Purpose: Corneal collagen crosslinking (CXL) through an intact epithelium (epi-on) at high irradiance could potentially improve patient comfort, visual recovery, and clinical workflow compared to conventional epi-off CXL. However, intact epithelium limits stromal delivery of the oxygen, photosensitizer, and ultraviolet-A (UV-A) radiation needed to drive CXL. This ex vivo study evaluated three different epi-on CXL protocols compared to positive and negative controls, specifically focusing on the impact of supplemental oxygen. Endpoints included stromal oxygen levels, stiffness of crosslinked tissue, and acute flattening of whole eyes.Materials & Methods: Ex vivo porcine eyes were held in a custom environmental chamber. Intrastromal oxygen levels were continuously measured before, during, and after UV illumination by a fiberoptic probe inserted into a laser-cut flap. Accelerated, high irradiance, epi-on CXL protocols using riboflavin formulated with benzalkonium chloride (BAC) were studied, with and without supplemental oxygen. These were compared to an alternate, low irradiance, epi-on protocol using riboflavin formulated with sodium iodide. Both negative (no CXL) and positive (epi-off modified Dresden protocol) controls were performed. Post-CXL elastic modulus was measured using extensiometry and anterior tangential curvature was measured using a Scheimpflug tomographer.Results: Protocols including supplemental oxygen resulted in an approximately 5-fold increase in stromal oxygen levels prior to CXL. During epi-on, high-irradiance UV-A delivery under hyperoxic conditions, an aerobic state was maintained. Conversely, under normoxic conditions, stromal oxygen rapidly depleted to 0-5% for all other protocols. The combination of supplemental oxygen, BAC formulation, and high-irradiance UV-A resulted in the largest biomechanical changes and most pronounced flattening effects of the three epi-on protocols.Conclusions: Ex vivo analysis of stromal oxygen levels, corneal stiffness, and acute anterior curvature change indicates that simultaneous optimization of the oxygen environment, riboflavin formulation, and UV-A protocol can significantly increase the effects of corneal collagen crosslinking.
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Affiliation(s)
- Jason Hill
- Research & Development, Avedro, Inc, Waltham, MA, USA
| | - Cailing Liu
- Research & Development, Avedro, Inc, Waltham, MA, USA
| | | | | | | | | | - Dan Gore
- Moorfields Eye Hospital, London, UK
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Al Zubi K, Albakar Y, Nasser R. Transepithelial versus Epithelium off Crosslinking for Treating Keratoconus among Jordanians. Open Ophthalmol J 2019. [DOI: 10.2174/1874364101913010008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
The progression of keratoconus is stabilized with the help of corneal collagen cross-linking (CXL) supported through photosynthesized riboflavin.
Objective:
This study aims to compare the effectiveness of the transepithelial procedure and epithelium off procedure of corneal collagen crosslinking among keratoconus patients in Jordan.
Methods:
The study recruited 80 patients suffering from progressive keratoconus, from a tertiary care setting in Jordan. These participants were randomly divided into two groups; group 1 with 40 participants subjected to transepithelial (Corneal collagen cross-linking) CXL; and 40 participants in group 2 received conventional epithelium off CXL.
Results:
Improvement was observed in the mean contact lens, which corrected distance visual acuity (CDVA) from logMAR 0.332 ± 0.09 (group 1), 0.35 ± 0.09 (group 2) to 0.241 ± 0.07 (group 1), 0.21 ± 0.07 (group 2), respectively at the end of follow-up (12 months). The mean pachymetry improved from 429.81 ± 18.96 μm (group 1), 430.08 ± 17.05 μm (group 2) to 436.5 ± 15.49 μm (group 1), 436.44 ± 12.53 μm (group 2), respectively, after twelve months. Additionally, the mean Sim K astigmatism declined from 7.0 ± 2.0 (group 1), 6.73 ± 1.98 (group 2) to 5.97 ± 1.88 (group 1), 5.53 ± 0.08 (group 2) respectively at twelve months post-treatment. Majority of the patients in group 2 experienced more pain as compared to group 1 participants.
Conclusion:
The effectiveness of a cross-linking procedure related to keratometry readings and corneal thickness showed that conventional (epithelium off) CXL method is more effective than transepithelial CXL.
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Chen S, Chan TCY, Zhang J, Ding P, Chan JCK, Yu MCY, Li Y, Jhanji V, Wang Q. Epithelium-on corneal collagen crosslinking for management of advanced keratoconus. J Cataract Refract Surg 2018; 42:738-49. [PMID: 27255251 DOI: 10.1016/j.jcrs.2016.02.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/29/2016] [Accepted: 02/01/2016] [Indexed: 11/30/2022]
Abstract
PURPOSE To report the 1-year visual and keratometric results of epithelium-on corneal collagen crosslinking (CXL) for advanced keratoconus (median maximum keratometry [K] ≥58.0 diopters [D]). SETTING School of Ophthalmology and Optometry and Eye Hospital of Wenzhou Medical College, Wenzhou, China. DESIGN Prospective case series. METHODS Patients with bilateral progressive keratoconus had tetracaine-enhanced epithelium-on CXL. The worse eye had CXL, and the fellow eye was not treated. Results were reported 1, 3, 6, and 12 months postoperatively. The outcomes were compared with those in the fellow untreated eyes. RESULTS Twenty-one eyes of 21 patients with a median age of 20.4 years (interquartile range [IQR], 9.5 years) were treated. A significant improvement in postoperative uncorrected distance visual acuity was observed at 12 months (P = .002). Postoperative corrected distance visual acuity improved at 6 months and 12 months (P ≤ .009) compared with baseline values. The maximum K decreased by 1.63 D from the median preoperative maximum K of 62.7 D (IQR, 12.9 D) at 12 months (P < .001). The reduction in maximum K was higher after CXL than in untreated eyes at the end of 12 months (P = .001). Correlation analysis between the preoperative maximum K values and the change over 6 to 12 months between different studies showed a significant correlation (r = -0.764, P < .001; Spearman correlation). CONCLUSIONS Epithelium-on CXL was an effective treatment for patients with advanced keratoconus. A higher preoperative maximum K value correlated with greater corneal flattening after CXL. FINANCIAL DISCLOSURE None of the authors has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Shihao Chen
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
| | - Tommy C Y Chan
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
| | - Jia Zhang
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
| | - Ping Ding
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
| | - Jason C K Chan
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
| | - Marco C Y Yu
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
| | - Yini Li
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
| | - Vishal Jhanji
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China.
| | - Qinmei Wang
- From the Department of Ophthalmology (Chen, Zhang, Ding, Li, Wang), Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, the Department of Ophthalmology and Visual Sciences (T.C.Y. Chan, Jhanji), Chinese University of Hong Kong, and Hong Kong Eye Hospital (T.C.Y. Chan, J.C.K. Chan, Jhanji), Mongkok, Kowloon, and the Department of Mathematics and Statistics (Yu), Hang Seng Management College, Hong Kong, China
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Hatami-Marbini H. Influence of Microstructure on Stiffening Effects of Corneal Cross-linking Treatment. J Refract Surg 2018; 34:622-627. [DOI: 10.3928/1081597x-20180718-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 07/09/2018] [Indexed: 11/20/2022]
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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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Efficacy of Epithelium-Off and Epithelium-On Corneal Collagen Cross-Linking in Pediatric Keratoconus. Eye Contact Lens 2017; 43:155-161. [PMID: 26925536 DOI: 10.1097/icl.0000000000000255] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To evaluate the efficacy of riboflavin/ultraviolet A epithelium-off (epi-off) and epithelium-on (epi-on) corneal collagen cross-linking (CXL) in progressive pediatric keratoconus. METHODS Thirty-six eyes of 27 patients aged 18 years or younger (12-18 years) diagnosed with progressive keratoconus and treated with epi-off (n=18 eyes) or epi-on (n=18 eyes) CXL were included in this study. All patients were followed up for 24 months postoperatively. RESULTS At 24-month follow-up, the mean corrected distance visual acuity (CDVA) improved from 0.24±0.17 to 0.17±0.11 logMAR in the epi-off group (P=0.032). In the epi-on group, CDVA improved from 0.33±0.23 to 0.26±0.20 logMAR (P=0.012), but the improvement was not significantly different between groups (P>0.05). In the epi-off group, all mean K values improved: K1 (Δ=-0.63 D, P=0.024), K2 (Δ=-0.73 D, P=0.008), and Kmax (Δ=-1.4 D, P=0.035), whereas in the epi-on group, Kmax and K2 did not change significantly and K1 (Δ=0.68 D, P=0.029) significantly worsened. Postoperative mild corneal haze occurred in 5 eyes (28%) in the epi-off group. No postoperative complications were observed in the epi-on group. In 94.4% of the epi-off group, keratoconus regressed (44.4%) or stabilized (50.0%), whereas in the epi-on group, only 66.6% regressed (33.3%) or stabilized (33.3%), and the difference was significant (P=0.038). CONCLUSIONS The efficacy of the epi-on procedure in terms of its ability to halt keratoconus progression appears to be 0.70 of the efficacy of epi-off CXL.
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Rossi S, Santamaria C, Boccia R, De Rosa L, D'Alterio FM, Simonelli F, De Rosa G. Standard, transepithelial and iontophoresis corneal cross-linking: clinical analysis of three surgical techniques. Int Ophthalmol 2017; 38:2585-2592. [PMID: 29185116 DOI: 10.1007/s10792-017-0772-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 11/22/2017] [Indexed: 11/25/2022]
Abstract
BACKGROUND To evaluate the clinical results of standard, transepithelial (TE) and iontophoresis (I) corneal cross-linking (CXL), in patients with progressive keratoconus. METHODS Thirty eyes of 30 patients with progressive keratoconus treated by CXL (10 by standard-CXL, 10 by TE-CXL and 10 by I-TE-CXL) with 12 months of follow-up. Pre- and postoperative ophthalmologic testing were: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive examination (spherical error, spherical equivalent), corneal topography (corneal astigmatism, simulated maximum, minimum and average keratometry), aberrometry (coma and spherical aberration), pachymetry and endothelial cell density. RESULTS In all groups, UDVA and CDVA improved significantly after treatment. Furthermore, a significant improvement in spherical error, spherical equivalent, topographic and aberrometric outcomes was observed in 3 groups at 1 year posttreatment. No significant variations were recorded in corneal thickness and endothelial cellular density. CONCLUSION Our results showed efficacy, clinical and refractive stability after standard-CXL, TE-CXL and iontophoresis-CXL.
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Affiliation(s)
- Settimio Rossi
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", Via Sergio Pansini 5, 80131, Naples, Italy.
| | | | - Rosa Boccia
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Luigi De Rosa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Francesco Maria D'Alterio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Giuseppe De Rosa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", Via Sergio Pansini 5, 80131, Naples, Italy
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Vastardis I, Pajic-Eggspuehler B, Nichorlis C, Mueller J, Pajic B. Recent Innovations in Collagen Corneal Cross-linking; a Mini Review. Open Ophthalmol J 2017; 11:217-224. [PMID: 28932338 PMCID: PMC5585451 DOI: 10.2174/1874364101711010217] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 03/13/2017] [Accepted: 06/14/2017] [Indexed: 11/22/2022] Open
Abstract
Background: The introduction of corneal cross-linking (CXL) with ultraviolet-A (UVA) and Riboflavin photosensitizer (Vit B2) from Seiler et al., revolutionized the treatment of Keratoconus and other corneal ectatic diseases. Today, the commonly known epithelium off Dresden protocol is in clinical use for the last 15 years with great success and regarded by many as the golden standard. Methods: With several studies demonstrating its simplicity, efficacy and safety this revolutionary method, paved the way for new therapies and strategies in the treatment of corneal ectatic diseases and changed our understanding in corneal biomechanics. Recent scientific and technological advances enabled the creation of various modifications of the initial CXL protocol and the formation of new ones. Conclusion: This work highlights the recent advances of CXL, such as the role of oxygen, higher fluence and shorter irradiation times as well as the various clinical applications and updates of this method.
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Affiliation(s)
- Iraklis Vastardis
- Swiss Eye Research Foundation, Eye Clinic ORASIS, Titlisstrasse 44, 5734 Reinach, Switzerland
| | | | - Charis Nichorlis
- Swiss Eye Research Foundation, Eye Clinic ORASIS, Titlisstrasse 44, 5734 Reinach, Switzerland
| | - Jörg Mueller
- Swiss Eye Research Foundation, Eye Clinic ORASIS, Titlisstrasse 44, 5734 Reinach, Switzerland.,University of Novi Sad, Faculty of Physics, Novi Sad, Serbia
| | - Bojan Pajic
- Swiss Eye Research Foundation, Eye Clinic ORASIS, Titlisstrasse 44, 5734 Reinach, Switzerland.,University of Novi Sad, Faculty of Physics, Novi Sad, Serbia.,Medical faculty, Military Medical Academy, University of defence Belgrade, Serbia
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Lombardo G, Micali NL, Villari V, Leone N, Serrao S, Rusciano D, Lombardo M. Assessment of stromal riboflavin concentration–depth profile in nanotechnology-based transepithelial corneal crosslinking. J Cataract Refract Surg 2017; 43:680-686. [DOI: 10.1016/j.jcrs.2017.03.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/15/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
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Cruzat A, Shukla AN, Arafat SN, Alageel S, Colon C, Chodosh J, Ciolino JB. Ex Vivo Study of Transepithelial Corneal Cross-linking. J Refract Surg 2017; 33:171-177. [DOI: 10.3928/1081597x-20161206-04] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 11/10/2016] [Indexed: 11/20/2022]
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Kling S, Hammer A, Conti A, Hafezi F. Corneal Cross-Linking with Riboflavin and UV-A in the Mouse Cornea in Vivo: Morphological, Biochemical, and Physiological Analysis. Transl Vis Sci Technol 2017; 6:7. [PMID: 28149672 PMCID: PMC5283086 DOI: 10.1167/tvst.6.1.7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/11/2016] [Indexed: 11/24/2022] Open
Abstract
Purpose To morphologically, biochemically, and physiologically characterize corneal cross-linking with riboflavin and UV-A light (CXL) in a newly established in vivo murine model. Methods C57BL/6 wild-type mice (N = 67) were treated with various CXL protocols, with modification of the following parameters: total energy (fluence) used, duration of UV-A irradiation, continuous versus pulsed irradiation, and CXL under hypoxic conditions (contact lens). Corneas were evaluated biomicroscopically, histologically, and using optical coherence tomography. Conformational collagen changes were evaluated via changes in the speed of enzymatic digestion. Results A fluence of 5.4 J/cm2 induced scar formation, while fluences of < 0.18 J/cm2 induced neovascularization. Fluences between 1.62 and 2.7 J/cm2 reduced epithelial thickness, but maintained a transparent cornea after 1 month. Pulsed UV irradiation inhibited neovascularization, but favored scar formation. Changes in the speed of enzymatic digestion suggest that CXL in mice, when compared to humans, requires less UV-A energy than the difference in corneal thickness between the species would suggest. Conclusions We demonstrated the in vivo response of very strong and very weak CXL and identified the best suited range of UV fluence in murine corneas. The presented murine CXL model may be helpful in future research addressing cellular and molecular pathways associated to CXL treatment. Translational Relevance Adverse tissue reactions following CXL treatment were observed, if the administered UV energy was out of the treatment window—raising concern about novel CXL treatment protocols that have not been previously validated in an experimental setting.
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Affiliation(s)
- Sabine Kling
- Laboratory of Ocular Cell Biology, University of Geneva, Geneva, Switzerland ; Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
| | - Arthur Hammer
- Laboratory of Ocular Cell Biology, University of Geneva, Geneva, Switzerland
| | - Alain Conti
- Laboratory of Ocular Cell Biology, University of Geneva, Geneva, Switzerland
| | - Farhad Hafezi
- Laboratory of Ocular Cell Biology, University of Geneva, Geneva, Switzerland ; Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland ; Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA ; ELZA Institute, Dietikon/Zurich, Switzerland
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Aixinjueluo W, Usui T, Miyai T, Toyono T, Sakisaka T, Yamagami S. Accelerated transepithelial corneal cross-linking for progressive keratoconus: a prospective study of 12 months. Br J Ophthalmol 2017; 101:1244-1249. [PMID: 28057642 DOI: 10.1136/bjophthalmol-2016-309775] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/12/2016] [Accepted: 12/11/2016] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS To evaluate the clinical results of accelerated transepithelial corneal cross-linking (CXL) in Japanese patients with progressive keratoconus (KCN). METHODS Thirty eyes of 19 patients (16 male, 3 female patients) with progressive KCN were included. The mean age was 24.9±7.0 (range 16-38) years. All patients received ultraviolet A radiation for 3 min at an irradiance of 30 mW/cm2. Patients were followed up on the first day, at 1 week and 2 weeks, and at 1 month, 3 months, 6 months and 12 months postoperatively. Clinical examinations included measures of uncorrected visual acuity, best corrected visual acuity (BCVA), average keratometry (AveK), maximum keratometry (Kmax), central corneal thickness, thinnest corneal thickness (TCT), endothelial cell density, intraocular pressure and non-mydriatic indirect fundus examination. Patients were asked to report any pain or discomfort at each visit. RESULTS There were no intraoperative or postoperative complications. All 30 eyes finished the follow-up. After 12 months, there was a significant decrease in Kmax (p<0.0001), AveK (p=0.003) and TCT (p=0.002), and a significant improvement in BCVA (p=0.001). There were no other significant changes. Pain or foreign-body sensation following CXL appeared in the first 2 days, but lasted no more than 1 week in all cases. CONCLUSIONS There were no complications associated with accelerated transepithelial corneal CXL, and the clinical outcomes were appraisable in a 12-month follow-up. TRIAL REGISTRATION NUMBER UMIN000009372.
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Affiliation(s)
- Wei Aixinjueluo
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomohiko Usui
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Takashi Miyai
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tetsuya Toyono
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Toshihiro Sakisaka
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Satoru Yamagami
- Division of Ophthalmology, Department of Visual Sciences, Nihon University, Chiyoda-ku, Japan
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Corneal collagen crosslinking for corneal ectasias: a review. Eur J Ophthalmol 2016; 27:253-269. [PMID: 28009397 DOI: 10.5301/ejo.5000916] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2016] [Indexed: 11/20/2022]
Abstract
PURPOSE To review the published literature on corneal collagen crosslinking (CXL). METHODS Importance has been placed on seminal publications, systemic reviews, meta-analyses, and randomized controlled clinical trials. Where such evidence was not available, cohort studies, case-controlled studies, and case series with follow-up greater than 12 months were examined. RESULTS Corneal collagen crosslinking with riboflavin and ultraviolet A (UVA) 370 nm radiation appears to be capable of arresting the progression of ectatic corneal disorders, with most studies reporting significant improvements in visual, keratometric, and topographic measurements. Its mode of action at the molecular level is undetermined. Follow-up is limited to 5-10 years but suggests sustained stability and enhancement in corneal shape with time. Nearly all published long-term data and comparative studies are with epithelium-off techniques. Epithelium-on investigations suggest some efficacy but less than with epithelium-off treatments and long-term data are unavailable. Accelerated techniques with higher UVA fluencies and shorter treatments times, delivering the same UVA energy dosage, are the subject of recent investigation, with some laboratory and clinical studies suggesting reduced efficacy compared to the standard 3 mW/cm2 for 30 minutes irradiation procedure. Combined methodologies of CXL with techniques such as photorefractive keratectomy and intrastromal rings show promise but long-term follow-up is indicated. Sight-threatening complications of CXL are rare. CONCLUSIONS Studies of epithelium-off CXL with irradiation at 3 mW/cm2 for 30 minutes support its efficacy. Refinement in techniques may allow for safer and more rapid procedures with less patient discomfort but require further investigation.
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Ameen SS, Mehboob MA, Ali K. Efficacy and safety of transepithelial collagen cross linking for progressive keratoconus. Pak J Med Sci 2016; 32:1111-1115. [PMID: 27882004 PMCID: PMC5103116 DOI: 10.12669/pjms.325.10922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective: To evaluate the efficacy and safety of transepithelial (TE) collagen cross-linking (CXL) in patients with progressive keratoconus (KC). Methods: This Quasi Experimental Study was conducted at PNS Shifa Naval Hospital, Karachi from June 2015 to June 2016. Sixty eyes of 32 patients who underwent TE CXL for progressive KC from June 2015 to June 2016 were analysed to ascertain efficacy and safety of TE CXL procedure. Statistical analysis of the data was done using SPSS version 17.0. Results: Twenty eight (87.5%) patients underwent TE CXL bilaterally, while 4 (12.5%) underwent unilateral CXL. Mean change in astigmatism, Maximum simulated Keratometry value (Kmax), Spherical equivalent (SE) and Central Corneal Thickness (CCT) were -0.67±0.35D, 1.28±0.64D, -0.58±0.17D and 0.40±7.58µm respectively, from baseline. Mean gain in lines on Snellen’s visual acuity chart was 1.13±0.83 lines. Changes in astigmatism, Kmax and SE were statistically significant (p<0.001), while change in CCT was not statistically significant. The procedure had excellent safety profile, with no major complication till 6 months follow up period. Conclusion: TE CXL is a safe and effective procedure with statistically significant reduction in corneal astigmatism, Kmax and SE with reasonable gain in Snellen’s visual acuity.
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Affiliation(s)
- Sameer Shahid Ameen
- Prof. Sameer Shahid Ameen, MCPS, FCPS. Department of Ophthalmology, PNS Shifa Naval Hospital, Karachi, Pakistan
| | - Mohammad Asim Mehboob
- Dr. Mohammad Asim Mehboob, MBBS. Department of Ophthalmology, PNS Shifa Naval Hospital, Karachi, Pakistan
| | - Kashif Ali
- Dr. Kashif Ali, FCPS. Department of Ophthalmology, PNS Shifa Naval Hospital, Karachi, Pakistan
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Aldahlawi NH, Hayes S, O'Brart DPS, O'Brart ND, Meek KM. An investigation into corneal enzymatic resistance following epithelium-off and epithelium-on corneal cross-linking protocols. Exp Eye Res 2016; 153:141-151. [PMID: 27765574 PMCID: PMC5131611 DOI: 10.1016/j.exer.2016.10.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/10/2016] [Accepted: 10/14/2016] [Indexed: 11/28/2022]
Abstract
The aim of this study was to investigate corneal enzymatic resistance following epithelium off and on riboflavin/UVA cross-linking (CXL). One hundred and fourteen porcine eyes were divided into four non-irradiated control groups and seven CXL groups. The latter comprised; (i) epithelium-off, 0.1% iso-osmolar riboflavin, 9 mW UVA irradiation for 10 min, (ii) disrupted epithelium, 0.1% hypo-osmolar riboflavin, 9 mW UVA for 10 min, (iii) epithelium-on, 0.25% hypo-osmolar riboflavin with 0.01% benzylalkonium chloride (BACS), 9 mW UVA for 10 min, (iv) epithelium-on, 5 min iontophoresis at 0.1 mA for 5 min with 0.1% riboflavin solution, 9 mW UVA for 10 min or (v) 12.5 min, (vi) epithelium-on, prolonged iontophoresis protocol of 25 min with 1.0 mA for 5 min and 0.5 mA for 5 min with 0.25% riboflavin with 0.01% BACS, 9 mW UVA for 10 min or (vii) 12.5 min. Enzymatic resistance was assessed by daily measurement of a corneal button placed in pepsin solution and measurement of corneal button dry weight after 11 days of digestion. This study revealed that the enzymatic resistance was greater in CXL corneas than non-irradiated corneas (p < 0.0001). Epithelium-off CXL showed the greatest enzymatic resistance (p < 0.0001). The prolonged iontophoresis protocol was found to be superior to all other trans-epithelial protocols (p < 0.0001). A 25% increase in UVA radiance significantly increased corneal enzymatic resistance (p < 0.0001). In conclusion, although epithelium-on CXL appears to be inferior to epithelium-off CXL in terms of enzymatic resistance to pepsin digestion, the outcome of epithelium-on CXL may be significantly improved through the use of higher concentrations of riboflavin solution, a longer duration of iontophoresis and an increase in UVA radiance. Epi-off CXL is superior to epi-on CXL in terms of enzymatic resistance. Epi-on CXL effectiveness can be improved by using a prolonged iontophoresis protocol. Higher riboflavin concentrations and increased UVA radiance may also enhance epi-on CXL.
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Affiliation(s)
- Nada H Aldahlawi
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Sally Hayes
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - David P S O'Brart
- Keratoconus Research Institute, Department of Ophthalmology, St Thomas Hospital, London, SE1 7EH, UK
| | - Naomi D O'Brart
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Keith M Meek
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK.
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Bersanetti PA, Bueno TLN, Morandim-Giannetti ADA, Nogueira RF, Matos JR, Schor P. Characterization of Rabbit Corneas Subjected to Stromal Stiffening by the Açaí Extract (Euterpe oleracea). Curr Eye Res 2016; 42:528-533. [DOI: 10.1080/02713683.2016.1214970] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Patrícia A. Bersanetti
- Departamento de Informática em Saúde, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
- Departamento de Oftalmologia e Ciências Visuais, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Tatiane L. N. Bueno
- Departamento de Oftalmologia e Ciências Visuais, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Regina F. Nogueira
- Departamento de Informática em Saúde, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Jivaldo R. Matos
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Brazil
| | - Paulo Schor
- Departamento de Oftalmologia e Ciências Visuais, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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Lombardo M, Micali N, Villari V, Serrao S, Pucci G, Barberi R, Lombardo G. Ultraviolet A: Visible spectral absorbance of the human cornea after transepithelial soaking with dextran-enriched and dextran-free riboflavin 0.1% ophthalmic solutions. J Cataract Refract Surg 2016; 41:2283-90. [PMID: 26703306 DOI: 10.1016/j.jcrs.2015.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/26/2015] [Accepted: 05/16/2015] [Indexed: 11/15/2022]
Abstract
PURPOSE To evaluate the stromal concentration of 2 commercially available transepithelial riboflavin 0.1% solutions in human donor corneas with the use of spectrophotometry. SETTING University of Calabria, Rende, Italy. DESIGN Experimental study. METHODS The absorbance spectra of 12 corneal tissues were measured in the 330 to 700 nm wavelength range using a purpose-designed spectrophotometry setup before and after transepithelial corneal soaking with a 15% dextran-enriched riboflavin 0.1% solution (n = 6) or a hypotonic dextran-free riboflavin 0.1% solution (n = 6). Both ophthalmic solutions contained ethylenediaminetetraacetic acid and trometamol as enhancers. In addition, 4 deepithelialized corneal tissues underwent stromal soaking with a 20% dextran-enriched riboflavin 0.1% solution and were used as controls. All the riboflavin solutions were applied topically for 30 minutes. The stromal concentration of riboflavin was quantified by analysis of absorbance spectra of the cornea collected before and after application of each solution. RESULTS The mean stromal riboflavin concentration was 0.012% ± 0.003% (SD), 0.0005% ± 0.0003% (P < .001), and 0.004% ± 0.001% (P < .01) in tissues soaked with 20% dextran-enriched, 15% dextran-enriched, and hypotonic dextran-free solutions, respectively. The difference of stromal riboflavin concentration between the 2 transepithelial solutions was statistically significant (P < .01). CONCLUSIONS Dextran-enriched solutions required complete corneal deepithelialization to permit effective stromal soaking with riboflavin. Nevertheless, riboflavin in hypotonic dextran-free solution with enhancers permeates across stroma through an intact epithelium. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Marco Lombardo
- From the Fondazione G.B. Bietti-IRCCS (M. Lombardo, Serrao), Vision Engineering Italy srl (G. Lombardo), Rome, Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (Micali, Villari, G. Lombardo), Messina, and the Department of Physics (Pucci, Barberi), University of Calabria, Rende, Italy.
| | - Norberto Micali
- From the Fondazione G.B. Bietti-IRCCS (M. Lombardo, Serrao), Vision Engineering Italy srl (G. Lombardo), Rome, Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (Micali, Villari, G. Lombardo), Messina, and the Department of Physics (Pucci, Barberi), University of Calabria, Rende, Italy
| | - Valentina Villari
- From the Fondazione G.B. Bietti-IRCCS (M. Lombardo, Serrao), Vision Engineering Italy srl (G. Lombardo), Rome, Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (Micali, Villari, G. Lombardo), Messina, and the Department of Physics (Pucci, Barberi), University of Calabria, Rende, Italy
| | - Sebastiano Serrao
- From the Fondazione G.B. Bietti-IRCCS (M. Lombardo, Serrao), Vision Engineering Italy srl (G. Lombardo), Rome, Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (Micali, Villari, G. Lombardo), Messina, and the Department of Physics (Pucci, Barberi), University of Calabria, Rende, Italy
| | - Giuseppe Pucci
- From the Fondazione G.B. Bietti-IRCCS (M. Lombardo, Serrao), Vision Engineering Italy srl (G. Lombardo), Rome, Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (Micali, Villari, G. Lombardo), Messina, and the Department of Physics (Pucci, Barberi), University of Calabria, Rende, Italy
| | - Riccardo Barberi
- From the Fondazione G.B. Bietti-IRCCS (M. Lombardo, Serrao), Vision Engineering Italy srl (G. Lombardo), Rome, Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (Micali, Villari, G. Lombardo), Messina, and the Department of Physics (Pucci, Barberi), University of Calabria, Rende, Italy
| | - Giuseppe Lombardo
- From the Fondazione G.B. Bietti-IRCCS (M. Lombardo, Serrao), Vision Engineering Italy srl (G. Lombardo), Rome, Consiglio Nazionale delle Ricerche-Istituto per i Processi Chimico Fisici (Micali, Villari, G. Lombardo), Messina, and the Department of Physics (Pucci, Barberi), University of Calabria, Rende, Italy
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Gatzioufas Z, Raiskup F, O'Brart D, Spoerl E, Panos GD, Hafezi F. Transepithelial Corneal Cross-linking Using an Enhanced Riboflavin Solution. J Refract Surg 2016; 32:372-7. [DOI: 10.3928/1081597x-20160428-02] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 02/04/2016] [Indexed: 02/07/2023]
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Transepithelial Versus Epithelium-Off Corneal Collagen Cross-Linking for Progressive Keratoconus: A Prospective Randomized Controlled Trial. Cornea 2016; 34 Suppl 10:S53-6. [PMID: 26266436 DOI: 10.1097/ico.0000000000000547] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To compare the safety and efficacy of transepithelial with epithelium-off corneal cross-linking for progressive keratoconus. METHODS In a prospective clinical trial, 70 patients with progressive keratoconus were randomized to undergo corneal cross-linking with intact epithelium (n = 34) or after deepithelialization (n = 36). The main outcome measure was a change in the maximum K reading (K(max)). RESULTS With 3-year follow-up, K(max) decreased in the epithelium-off group with a mean of 2.4 D and no patient showed evidence of progression. In the transepithelial group, K(max) increased by a mean of 1.1 D, and 20 patients (55%) showed progression of keratoconus. CONCLUSIONS In this study, epithelium-off was significantly more effective than transepithelial corneal cross-linking in halting the progression of keratoconus (P < 0.0001).
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McQuaid R, Mrochen M, Vohnsen B. Rate of riboflavin diffusion from intrastromal channels before corneal crosslinking. J Cataract Refract Surg 2016; 42:462-8. [PMID: 27063528 DOI: 10.1016/j.jcrs.2015.09.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/18/2015] [Accepted: 09/28/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE To determine the diffusion of riboflavin from intrastromal channels through the effective diffusion coefficients compared with traditional axial diffusion with epithelium on or off. SETTING Advanced Optical Imaging Laboratory, University College Dublin, and Wellington Eye Clinic, Sandyford, Dublin, Ireland. DESIGN Experimental study. METHODS The rate of diffusion in whole-mounted porcine eyes was monitored for a 30 minutes using an optical setup with a charge-coupled device camera and a bandpass filter (central wavelength 550 nm and 40 nm bandpass) to image the fluorescence under ultraviolet illumination (365 nm wavelength). For comparison, an isotropic corneal stroma with an annular channel was modeled numerically for different diffusion constants and boundary conditions. RESULTS Numerical and experimental results were compared, allowing determination of the effective diffusion coefficient for each case. Experimental results for 6 different riboflavin solutions were in all cases found to be higher than for the common crosslinking (CXL) riboflavin protocol, where the diffusion constant is D0 = 6.5 × 10(-5) mm(2)/sec. For the intrastromal channel, 2 isotonic solutions containing riboflavin 0.1% correlated with a diffusion constant of 5D0 = 32.5 × 10(-5) mm(2)/sec. Hypotonic solutions and transepithelium had a higher diffusion coefficient approaching 10D0 = 65.0 × 10(-5) mm(2)/sec, which is an order-of-magnitude increase compared with the typical diffusion coefficient found in standard CXL. CONCLUSIONS In this study, riboflavin had a faster stromal diffusion when injected into a corneal channel than when applied as drops to the anterior corneal surface. Further numerical modeling might allow optimization of the channel structure for any specific choice of riboflavin.
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Affiliation(s)
- Rebecca McQuaid
- From the Advanced Optical Imaging Group (McQuaid, Vohnsen), School of Physics, University College Dublin, Dublin, Ireland, and IROC Science AG (Mrochen), Zurich, Switzerland.
| | - Michael Mrochen
- From the Advanced Optical Imaging Group (McQuaid, Vohnsen), School of Physics, University College Dublin, Dublin, Ireland, and IROC Science AG (Mrochen), Zurich, Switzerland
| | - Brian Vohnsen
- From the Advanced Optical Imaging Group (McQuaid, Vohnsen), School of Physics, University College Dublin, Dublin, Ireland, and IROC Science AG (Mrochen), Zurich, Switzerland
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Keratoconus and Other Corneal Diseases: Pharmacologic Cross-Linking and Future Therapy. Handb Exp Pharmacol 2016; 242:137-161. [PMID: 27815790 DOI: 10.1007/164_2016_23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ability to cross-link collagen fibers and use this technique to strengthen the cornea has become of great interest to ophthalmologists in the last decade. For progressive diseases such as keratoconus, collagen cross-linking confers the possibility of halting progression and stabilizing the cornea, a benefit that is not observed with any other current treatment. Collagen cross-linking uses riboflavin combined with ultraviolet A light to induce the formation of bonds between collagen fibrils that strengthen the cornea. This chapter will discuss the theory, technique, indications, and complications of corneal cross-linking. Much of what will be discussed is in areas of active research that will likely be further clarified as more experience is gained with this procedure.
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Le crosslinking du collagène dans le kératocône. J Fr Ophtalmol 2015; 38:445-62. [DOI: 10.1016/j.jfo.2014.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 12/07/2014] [Accepted: 12/09/2014] [Indexed: 11/20/2022]
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Bonnel S, Berguiga M, De Rivoyre B, Bedubourg G, Sendon D, Froussart-Maille F, Rigal-Sastourne JC. Demarcation line evaluation of iontophoresis-assisted transepithelial corneal collagen cross-linking for keratoconus. J Refract Surg 2015; 31:36-40. [PMID: 25599541 DOI: 10.3928/1081597x-20141218-04] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 10/23/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the visualization and depth of the demarcation line with anterior segment optical coherence tomography (AS-OCT) after iontophoresis-assisted transepithelial corneal collagen cross-linking (CXL). METHODS This prospective, consecutive, single center, non-randomized clinical study involved 15 eyes of 12 patients with keratoconus who underwent an AS-OCT scan (Spectralis; Heidelberg Engineering, Inc., Carlsbad, CA) to search for a demarcation line and its depth at 1 month after iontophoresis-assisted transepithelial CXL. AS-OCT scan measurements were performed by two independent examiners. RESULTS No intraoperative or postoperative complications were observed. Kappa coefficient estimation for operator agreement in demarcation line visualization (whether it was visualized) was 70.6%. The corneal stromal demarcation line was identified in 9 eyes (60%) by both examiners. Mean depth of the corneal stromal demarcation line was 246.67 ± 50.72 µm (range: 183 to 339 µm) for the first examiner and 241.89 ± 62.52 µm (range: 163 to 358 µm) for the second examiner. There were no statistically significant differences for the measurements of the paired comparisons between the two examiners (P = .61). The Pearson correlation coefficient between the measurements was 0.910. CONCLUSIONS Iontophoresis-assisted transepithelial CXL creates a demarcation line that can be visualized with AS-OCT, which seems less easily distinguishable and shallower than in conventional CXL. However, its depth and visualization seems to be more similar to conventional CXL than transepithelial CXL.
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Lombardo M, Serrao S, Carbone G, Lombardo G. Corneal light backscattering after transepithelial corneal crosslinking using iontophoresis in donor human corneal tissue. J Cataract Refract Surg 2015; 41:635-43. [DOI: 10.1016/j.jcrs.2014.07.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/24/2014] [Accepted: 07/27/2014] [Indexed: 10/23/2022]
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Neue Behandlungsprotokolle der Hornhautvernetzung (Corneal Crosslinking). SPEKTRUM DER AUGENHEILKUNDE 2015. [DOI: 10.1007/s00717-015-0257-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Nawaz S, Gupta S, Gogia V, Sasikala NK, Panda A. Trans-epithelial versus conventional corneal collagen crosslinking: A randomized trial in keratoconus. Oman J Ophthalmol 2015; 8:9-13. [PMID: 25709267 PMCID: PMC4333560 DOI: 10.4103/0974-620x.149855] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Purpose: The purpose was to compare transepithelial versus epithelium off technique of corneal collagen crosslinking (CXL) in patients of keratoconus. Materials and Method: Totally, 40 eyes (40 patients) with progressive keratoconus were subjected to transepithelial CXL (20 eyes; Group I), and conventional CXL (20 eyes; Group II). Patients were evaluated for uncorrected distance visual acuity, best corrected visual acuity (BCVA), slit lamp-biomicroscopy, keratometry, 9-point pachymentry, orbscan II, and endothelial cell count at baseline and post CXL at 1, 3, and 6 months. Results: The two groups were similar with respect to the evaluated parameters both at baseline and at the end of 6 months. There was an improvement in mean BCVA from Log Mar 0.327 ± 0.1 (Group 1), 0.36 ± 0.08 (Group 2) to 0.23 ± 0.08 (Group 1; P < 0.001), 0.22 ± 0.06 (Group 2; P < 0.001), respectively, at 6 months. Mean Sim K astigmatism decreased from 6.6 ± 1.93 D (Group 1), 6.64 ± 1.93 D (Group 2) to 5.14 ± 1.86 D (Group 1; P = 0.001), and 4.77 ± 0.06 (Group 2; P = 0.001), respectively, at 6 months. The mean pachymetry increased from 432.05 ± 19.36 μm (Group 1), 429.91 ± 16.66 μm (Group 2) to 447.8 ± 16.09 μm (Group 1; P < 0.001), 440.25 ± 11.18 um (Group 2; P = 0.002), respectively, at 6 months. All cases showed stabilization of keratoconus two eyes in epithelium off group developed persistent stromal haze. Most of the patients in Group II experienced pain and photophobia during first 2 days, but not of Group I. Conclusion: Trans-epithelial technique offers visual and topographic outcomes similar to the conventional method with superior patient comfort postintervention.
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Affiliation(s)
- Shah Nawaz
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Shikha Gupta
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Varun Gogia
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - N K Sasikala
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Anita Panda
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Interaction of ultraviolet light with the cornea: clinical implications for corneal crosslinking. J Cataract Refract Surg 2014; 41:446-59. [PMID: 25542349 DOI: 10.1016/j.jcrs.2014.12.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/23/2014] [Accepted: 09/24/2014] [Indexed: 11/21/2022]
Abstract
UNLABELLED Understanding ultraviolet (UV) interaction with the human corneal tissue is of interest among corneal specialists given the widespread application of corneal crosslinking. This article reviews the current knowledge of light interaction with the cornea in the UV wavelength range. It also uses a novel experimental study to illustrate the role of 2 important corneal properties that have not yet been clarified: the epithelial contribution to overall UVA corneal absorbance and the regional anisotropy of UVA light transmittance. Finally, it presents the most recent insights into how different methods of UVA light irradiation and corneal soaking with riboflavin influence the outcome of corneal crosslinking. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Kanellopoulos AJ, Asimellis G. Hyperopic correction: clinical validation with epithelium-on and epithelium-off protocols, using variable fluence and topographically customized collagen corneal crosslinking. Clin Ophthalmol 2014; 8:2425-33. [PMID: 25506204 PMCID: PMC4259508 DOI: 10.2147/opth.s68222] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To report novel application of topographically-customized collagen crosslinking aiming to achieve hyperopic refractive changes. Two approaches were evaluated, one based on epithelium-off and one based on epithelium-on (transepithelial). Methods A peripheral annular-shaped topographically customizable design was employed for high-fluence ultraviolet (UV)-A irradiation aiming to achieve hyperopic refractive changes. A total of ten eyes were involved in this study. In group-A (five eyes), a customizable ring pattern was employed to debride the epithelium by excimer laser ablation, while in group-B (also five eyes), the epithelium remained intact. In both groups, specially formulated riboflavin solutions were applied. Visual acuity, cornea clarity, keratometry, topography, and pachymetry with a multitude of modalities, as well as endothelial cell counts were evaluated. Results One year postoperatively, the following changes have been noted: in group-A, average uncorrected distance visual acuity changed from 20/63 to 20/40. A mean hyperopic refractive increase of +0.75 D was achieved. There was some mild reduction in the epithelial thickness. In group-B, average uncorrected distance visual acuity changed from 20/70 to 20/50. A mean hyperopic refractive increase of +0.85 D was achieved. Epithelial thickness returned to slightly reduced levels (compared to baseline) in group-A, whereas to slightly increased levels in group-B. Conclusion We introduce herein the novel application of a topographically-customizable collagen crosslinking to achieve a hyperopic refractive effect. This novel technique may be applied either with epithelial removal, offering a more stable result or with a non-ablative and non-incisional approach, offering a minimally invasive alternative.
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Affiliation(s)
- Anastasios John Kanellopoulos
- LaserViison.gr Clinical and Research Eye Institute, Athens, Greece ; Department of Ophthalmology, New York University Medical School, New York, NY, USA
| | - George Asimellis
- LaserViison.gr Clinical and Research Eye Institute, Athens, Greece
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Biomechanical changes in the human cornea after transepithelial corneal crosslinking using iontophoresis. J Cataract Refract Surg 2014; 40:1706-15. [DOI: 10.1016/j.jcrs.2014.04.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/25/2014] [Accepted: 04/07/2014] [Indexed: 11/23/2022]
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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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Imaging mass spectrometry by matrix-assisted laser desorption/ionization and stress-strain measurements in iontophoresis transepithelial corneal collagen cross-linking. BIOMED RESEARCH INTERNATIONAL 2014; 2014:404587. [PMID: 25276786 PMCID: PMC4167647 DOI: 10.1155/2014/404587] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/14/2014] [Indexed: 11/18/2022]
Abstract
PURPOSE To compare biomechanical effect, riboflavin penetration and distribution in transepithelial corneal collagen cross-linking with iontophoresis (I-CXL), with standard cross linking (S-CXL) and current transepithelial protocol (TE-CXL). MATERIALS AND METHODS The study was divided into two different sections, considering, respectively, rabbit and human cadaver corneas. In both sections corneas were divided according to imbibition protocols and irradiation power. Imaging mass spectrometry by matrix-assisted laser desorption/ionization (MALDI-IMS) and stress-strain measurements were used. Forty-eight rabbit and twelve human cadaver corneas were evaluated. RESULTS MALDI-IMS showed a deep riboflavin penetration throughout the corneal layers with I-CXL, with a roughly lower concentration in the deepest layers when compared to S-CXL, whereas with TE-CXL penetration was considerably less. In rabbits, there was a significant increase (by 71.9% and P = 0.05) in corneal rigidity after I-CXL, when compared to controls. In humans, corneal rigidity increase was not significantly different among the subgroups. CONCLUSIONS In rabbits, I-CXL induced a significant increase in corneal stiffness as well as better riboflavin penetration when compared to controls and TE-CXL but not to S-CXL. Stress-strain in human corneas did not show significant differences among techniques, possibly because of the small sample size of groups. In conclusion, I-CXL could be a valid alternative to S-CXL for riboflavin delivery in CXL, preserving the epithelium.
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O'Brart DPS. Corneal collagen cross-linking: a review. JOURNAL OF OPTOMETRY 2014; 7:113-24. [PMID: 25000866 PMCID: PMC4087180 DOI: 10.1016/j.optom.2013.12.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 11/14/2013] [Indexed: 05/04/2023]
Abstract
The aim was to review the published literature on corneal collagen cross-linking. The emphasis was on the seminal publications, systemic reviews, meta-analyses and randomized controlled trials. Where such an evidence did not exist, selective large series cohort studies, case controlled studies and case series with follow-up preferably greater than 12 months were included. Riboflavin/Ultraviolet A (UVA) corneal collagen cross-linking appears to be the first treatment modality to halt the progression of keratoconus and other corneal ectatic disorders with improvement in visual, keratometric and topographic parameters documented by most investigators. Its precise mechanism of action at a molecular level is as yet not fully determined. Follow-up is limited to 4-6 years at present but suggests continued stability and improvement in corneal shape with time. Most published data are with epithelium-off techniques. Epithelium-on studies suggest some efficacy but less than with the epithelium-off procedures and long-term data are not currently available. The use of Riboflavin/UVA CXL for the management of infectious and non-infectious keratitis appears very promising. Its use in the management of bullous keratopathy is equivocal. Investigation of other methodologies for CXL are under investigation.
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Affiliation(s)
- David P S O'Brart
- Keratoconus Research Institute, Department of Ophthalmology, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
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Corneal collagen cross-linking with and without epithelial removal: a contralateral study with 0.5% hypotonic riboflavin solution. BIOMED RESEARCH INTERNATIONAL 2014; 2014:619398. [PMID: 25050368 PMCID: PMC4090564 DOI: 10.1155/2014/619398] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/27/2014] [Indexed: 11/18/2022]
Abstract
PURPOSE Our main purpose was to compare safety and efficacy in the treatment of progressive keratoconus with "epithelium-on" and "epithelium-off" corneal collagen cross-linking (CXL). Our secondary purpose was to evaluate efficacy of CXL when hypotonic 0.5% riboflavin is used as photosensitizer. METHODS One eye of 20 patients with bilateral progressive keratoconus was randomly treated for "epithelium-on" CXL (group 1) while the fellow eye underwent "epithelium-off" CXL (group 2). Hypotonic 0.5% riboflavin was used in both groups. Visual acuity, refraction, corneal topography, and wavefront aberrometry were evaluated at baseline and after 1, 6, and 12 months. Specular microscopy was performed on 10 patients preoperatively and after 12 months. Postoperative pain was evaluated using a patient questionnaire. RESULTS Uncorrected and corrected distance visual acuity improved significantly in both groups. Refraction, topography, and aberrometry showed nonsignificant changes from the preoperative status throughout the 12-month follow-up in both groups. Moreover, the outcomes between the groups were comparable at all follow-up points. Endothelial cell-count was stable. Postoperative pain length was shorter in group 1 (P < 0.001). CONCLUSION "Epithelium-on" and "epithelium-off" CXL using hypotonic 0.5% riboflavin were equally safe and effective in stabilization of keratoconus. Topography and aberrometry outcomes in both groups failed to show any significant improvements. This study is registered at ClinicalTrials.gov: NCT01181219.
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Torricelli AAM, Ford MR, Singh V, Santhiago MR, Dupps WJ, Wilson SE. BAC-EDTA transepithelial riboflavin-UVA crosslinking has greater biomechanical stiffening effect than standard epithelium-off in rabbit corneas. Exp Eye Res 2014; 125:114-7. [PMID: 24929203 DOI: 10.1016/j.exer.2014.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 05/12/2014] [Accepted: 06/04/2014] [Indexed: 10/25/2022]
Abstract
Studies suggest that standard corneal collagen crosslinking (CXL) is a safe and effective treatment to stiffen the cornea for keratoconus and other ectatic corneal disorders. The purpose of the present study was to compare the biomechanical effects of transepithelial benzalkonium chloride-EDTA (BAC-EDTA) riboflavin-UVA crosslinking to standard epithelium-off riboflavin-UVA crosslinking in a rabbit model. Corneal stiffness was quantified using optical coherence elastography at two months after treatment. The mean lateral-to-axial displacement ratio for the BAC-EDTA transepithelial CXL group was lower (greater stiffness) [0.062 ± 0.042, mean ± SD] than epithelium-off CXL (mean ± SD: 0.065 ± 0.045) or untreated control eyes (0.069 ± 0.044). Using ANOVA with Tukey correction, a statistically significant difference was found between the BAC-EDTA transepithelial CXL group and standard epithelium-off CXL (p = 0.0019) or the untreated control (p < 0.0001) groups. A graph of the probability density functions for biomechanical stiffness also showed a greater shift in stiffening in the BAC-EDTA transepithelial CXL group than the standard epithelium-off CXL or untreated control group. These results demonstrated that the biomechanical stiffening effect produced by BAC-EDTA transepithelial CXL was greater than that produced by standard epithelium-off CXL in a rabbit model.
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Affiliation(s)
- Andre A M Torricelli
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; University of Sao Paulo, Sao Paulo, Brazil
| | - Matthew R Ford
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Vivek Singh
- LV Prasad Eye Institute, HERF, Hyderabad, AP, India
| | - Marcony R Santhiago
- University of Sao Paulo, Sao Paulo, Brazil; Federal University of Rio de Janeiro, Brazil
| | - William J Dupps
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA
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Sorkin N, Varssano D. Corneal Collagen Crosslinking: A Systematic Review. Ophthalmologica 2014; 232:10-27. [DOI: 10.1159/000357979] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 12/10/2013] [Indexed: 11/19/2022]
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Corneal cross-linking: intrastromal riboflavin concentration in iontophoresis-assisted imbibition versus traditional and transepithelial techniques. Am J Ophthalmol 2014; 157:623-30.e1. [PMID: 24321474 DOI: 10.1016/j.ajo.2013.11.018] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/18/2013] [Accepted: 11/20/2013] [Indexed: 11/22/2022]
Abstract
PURPOSE To determine differences in riboflavin concentration in the anterior, intermediate, and posterior stroma after 3 corneal cross-linking imbibition techniques (standard epithelial [epi]-off, epi-on, and iontophoresis-assisted administration) of 0.1% riboflavin. DESIGN Experimental laboratory investigation of human cadaver corneas not suitable for transplantation. METHODS Ten corneas underwent imbibition with epi-on (n = 3), epi-off (n = 3), iontophoresis (n = 3), and saline exposure (control; n = 1). Femtosecond laser was used to produce 3 8-mm discs of the superficial (0-150 μm), intermediate (150-300 μm), and deep stroma (>300 μm). Riboflavin concentration was measured with high-performance liquid chromatography. The main outcome measure was riboflavin concentration at the 3 evaluated depths. RESULTS The overall stromal concentration of riboflavin was 34.1 ± 7.1 μg/g in epi-off, 7.2 ± 3.7 μg/g in epi-on, and 15.0 ± 5.1 μg/g in iontophoresis. The mean riboflavin content in the superficial slice in the epi-off group was about 2-fold greater than that of the iontophoresis group (50.5 ± 5.3 μg/g and 23.6 ± 2.5 μg/g, respectively) and 4-fold greater than that of the epi-on group (11.7 ± 3.3 μg/g). Similar differences among the 3 groups were observed for the intermediate and posterior stromal slices, presenting an evident reduction of riboflavin concentration with increasing depth in all groups. Slice depth-dependent decrease in riboflavin concentration was statistically significant (general linear model (GLM); F1,6 = 62.265, P < .001), as was the group-dependent variation (GLM; F2,6 = 20.268, P = .002) and the slice depth group interaction (GLM; F2,6 = 18.004, P = .002). CONCLUSIONS Corneal cross-linking transepithelial iontophoresis imbibition yielded greater and deeper riboflavin saturation with respect to conventional epi-on, while maintaining the advantages of avoiding epithelial removal and shorter procedure time, but did not reach concentrations obtained with standard epi-off.
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