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Bradford S, Luo S, Brown D, Juhasz T, Jester J. A review of the epithelial and stromal effects of corneal collagen crosslinking. Ocul Surf 2023; 30:150-159. [PMID: 37683969 PMCID: PMC10993773 DOI: 10.1016/j.jtos.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/31/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
Induced corneal collagen crosslinking and mechanical stiffening via ultraviolet-A photoactivation of riboflavin (UVA CXL) is now a common treatment for corneal ectasia and Keratoconus. Some effects of the procedure such as induced mechanical stiffening, corneal flattening, and cellular toxicity are well-known, but others remain more controversial. Authors report a variety of contradictory effects, and provide evidence based on individual results and observations. A full understanding of the effects of and mechanisms behind this procedure are essential to predicting its outcome. A growing interest in modifications to the standard UVA CXL protocol, such as transepithelial or accelerated UVA CXL, makes analyzing the literature as a whole more urgent. This review presents an analysis of both the agreed-upon and contradictory results reported and the various methods used to obtain them.
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Affiliation(s)
- Samantha Bradford
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA.
| | - Shangbang Luo
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Donald Brown
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Tibor Juhasz
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - James Jester
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
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Toprak I, Cavas F, Velázquez JS, del Barrio JLA, Alio JL. A three-dimensional morpho-volumetric similarity study of Down syndrome keratopathy vs. keratoconus. EYE AND VISION (LONDON, ENGLAND) 2023; 10:4. [PMID: 36593521 PMCID: PMC9809058 DOI: 10.1186/s40662-022-00315-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 10/26/2022] [Indexed: 01/04/2023]
Abstract
BACKGROUND To compare and contrast morpho-volumetric features between Down syndrome (DS) cornea and non-DS keratoconic cornea by three-dimensional (3D) modelling. METHODS Forty-three subjects (43 eyes) with DS and 99 patients matching their age and sex (99 eyes) with keratoconus (KC) were included in this single-center cross-sectional study. Main outcome measures were high-order aberrations (HOA), central corneal thickness (CCT), spherical equivalent refraction, and morpho-volumetric parameters established using a 3D corneal model, such as deviation of anterior and posterior corneal apices (Dapexant/Dapexpost) and minimum thickness points (Dmctant/Dmctpost) from corneal vertex, areas of the anterior and posterior surfaces (Aant/Apost), sagittal area passing through the anterior and posterior corneal apices (Aapexant/Aapexpost) and minimum thickness point (Amctpost) and corneal volume of the complete cornea (Vtotal). RESULTS Age, gender, spherical equivalent refraction, CCT and Vtotal were similar between the net on-DS KC and DS groups (P > 0.05), while non-DS KC group had higher HOA than the DS group (P < 0.05). Dapexant, Aant, Apost and Aapexant showed higher values in the DS group than in the non-DS KC group, whereas Dapexpost showed a reduction in the DS group when compared with the non-DS KC group (P < 0.05). CONCLUSIONS This study demonstrated that anterior and posterior corneal apex dynamics were specifically different in DS subjects, as the anterior apex tends to displace more prominently when compared to that from the non-DS KC group, while the posterior apex appears to be more stable than that in non-DS KC, which also support the theory that DS patients suffer from a specific keratopathy, distinctively different to KC but strongly related to it, and probably showing a diversity of corneal phenotypes in all cases of DS.
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Affiliation(s)
- Ibrahim Toprak
- grid.411742.50000 0001 1498 3798Department of Ophthalmology, Faculty of Medicine, Pamukkale University, Denizli, Turkey
| | - Francisco Cavas
- grid.218430.c0000 0001 2153 2602Bioengineering and Applied Computational Simulation Research Group, Technical University of Cartagena, Cartagena, Spain ,grid.218430.c0000 0001 2153 2602Department of Structures, Construction and Graphical Expression, Technical University of Cartagena, Cartagena, Spain
| | - José S. Velázquez
- grid.218430.c0000 0001 2153 2602Bioengineering and Applied Computational Simulation Research Group, Technical University of Cartagena, Cartagena, Spain ,grid.218430.c0000 0001 2153 2602Department of Structures, Construction and Graphical Expression, Technical University of Cartagena, Cartagena, Spain
| | - Jorge L. Alio del Barrio
- grid.419256.dDepartment of Research and Development, VISSUM, Calle Cabañal, 1, Edificio Vissum, 03016 Alicante, Spain ,grid.419256.dCornea, Cataract and Refractive Surgery Department, VISSUM, Calle Cabañal, 1, Edificio Vissum, 03016 Alicante, Spain ,grid.26811.3c0000 0001 0586 4893Division of Ophthalmology, Department of Pathology and Surgery, Faculty of Medicine, Miguel Hernández University, Calle Cabañal, 1, Edificio Vissum, 03016 Alicante, Spain
| | - Jorge L. Alio
- grid.419256.dDepartment of Research and Development, VISSUM, Calle Cabañal, 1, Edificio Vissum, 03016 Alicante, Spain ,grid.419256.dCornea, Cataract and Refractive Surgery Department, VISSUM, Calle Cabañal, 1, Edificio Vissum, 03016 Alicante, Spain ,grid.26811.3c0000 0001 0586 4893Division of Ophthalmology, Department of Pathology and Surgery, Faculty of Medicine, Miguel Hernández University, Calle Cabañal, 1, Edificio Vissum, 03016 Alicante, Spain
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Tafti MF, Aghamollaei H, Moghaddam MM, Jadidi K, Alio JL, Faghihi S. Emerging tissue engineering strategies for the corneal regeneration. J Tissue Eng Regen Med 2022; 16:683-706. [PMID: 35585479 DOI: 10.1002/term.3309] [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: 11/23/2021] [Revised: 04/16/2022] [Accepted: 04/19/2022] [Indexed: 11/10/2022]
Abstract
Cornea as the outermost layer of the eye is at risk of various genetic and environmental diseases that can damage the cornea and impair vision. Corneal transplantation is among the most applicable surgical procedures for repairing the defected tissue. However, the scarcity of healthy tissue donations as well as transplantation failure has remained as the biggest challenges in confront of corneal grafting. Therefore, alternative approaches based on stem-cell transplantation and classic regenerative medicine have been developed for corneal regeneration. In this review, the application and limitation of the recently-used advanced approaches for regeneration of cornea are discussed. Additionally, other emerging powerful techniques such as 5D printing as a new branch of scaffold-based technologies for construction of tissues other than the cornea are highlighted and suggested as alternatives for corneal reconstruction. The introduced novel techniques may have great potential for clinical applications in corneal repair including disease modeling, 3D pattern scheming, and personalized medicine.
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Affiliation(s)
- Mahsa Fallah Tafti
- Stem Cell and Regenerative Medicine Group, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Hossein Aghamollaei
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | | | - Khosrow Jadidi
- Vision Health Research Center, Semnan University of Medical Sciences, Semnan, Iran
| | - Jorge L Alio
- Department of Research and Development, VISSUM, Alicante, Spain.,Cornea, Cataract and Refractive Surgery Department, VISSUM, Alicante, Spain.,Department of Pathology and Surgery, Division of Ophthalmology, Faculty of Medicine, Miguel Hernández University, Alicante, Spain
| | - Shahab Faghihi
- Stem Cell and Regenerative Medicine Group, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
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Ostadian F, Nickkhah S, Farrahi F, Rad AM. Evaluation of changes in corneal volume, volume and angle of anterior chamber in keratoconus patients using Pentacam after CXL. J Family Med Prim Care 2021; 10:3820-3824. [PMID: 34934686 PMCID: PMC8653477 DOI: 10.4103/jfmpc.jfmpc_721_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/19/2021] [Accepted: 07/30/2021] [Indexed: 11/16/2022] Open
Abstract
Introduction and Objective: Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) is a new technique of mechanical stability of the cornea and prevention of keratoconus progression. The present study aimed at the evaluation of the changes in the corneal volume (CV), volume, and the angle of anterior chamber in keratoconus patients using the Pentacam after CXL. Methods: This prospective study was performed on 48 eyes of 24 patients (including 12 men, 17–33 years old) with progressive keratoconus undergoing CXL treatment at collagen cross-linking Imam Khomeini Hospital in Ahvaz in 2019. The CV (CV) and anterior chamber parameters such as anterior chamber volume (ACV) and anterior chamber angle (ACA) were measured using the Pentacam before CXL and at 6 and 12 months after CXL. Also, all of the patients were evaluated in terms of best-corrected visual acuity (BCVA), during the follow-up. Results: The pre-CXL values of BCVA was significantly lower than the post-CXL values in 6 and 12 months (0.18 ± 0.11, 0.15 ± 0.10, and 0.11 ± 0.10, respectively, P < 0.0001). In general, there was a significant improvement in the BCVA (P < 0.0001), a significant decrease in the CV (P = 0.001), and a significant increase in the ACV (P < 0.0001), and angle (P < 0.0001) 6 and 12 months after CXL. Conclusion: It seems that CXL has a positive effect on the anterior chamber parameters (ACV and ACA) and CV after 6 months and 1 year in the treatment of keratoconus patients. In addition, the visual acuity improves after CXL. Finally, further studies with a higher sample size and longer follow-up periods are recommended.
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Affiliation(s)
- Farshad Ostadian
- Department of Ophthalmology, School of Medicine, Infectious Ophthalmologic Research Center, Ahvaz, Iran
| | - Sona Nickkhah
- Resident of Ophthalmology, Department of Ophthalmology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Fereydoun Farrahi
- Department of Ophthalmology, School of Medicine, Infectious Ophthalmologic Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Atefeh Mahdian Rad
- Department of Ophthalmology, School of Medicine, Infectious Ophthalmologic Research Center, Ahvaz, Iran
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Toprak I, Cavas F, Vega A, Velázquez JS, Alio del Barrio JL, Alio JL. Evidence of a Down Syndrome Keratopathy: A Three-Dimensional (3-D) Morphogeometric and Volumetric Analysis. J Pers Med 2021; 11:jpm11020082. [PMID: 33573177 PMCID: PMC7911434 DOI: 10.3390/jpm11020082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 01/06/2023] Open
Abstract
The aim of this study was to investigate whether a different and abnormal corneal profile is present in Down syndrome (DS) by personalized three-dimensional (3D) modelling. This single-centre cross-sectional study included 43 patients with DS (43 eyes) and 58 age-sex-matched control subjects (58 eyes) with normal karyotype and topography. Refraction, central corneal thickness (CCT), aberrations (high-order, coma and spherical), asphericity and morphogeometric/volumetric parameters based on a 3D corneal model that was generated from raw topographical data were evaluated. Deviation of anterior/posterior apex (Dapexant/Dapexpost) and thinnest point (Dmctant/Dmctpost) from corneal vertex, anterior/posterior surface area (Aant/Apost), sagittal area passing through the anterior/posterior apex (Aapexant/Aapexpost) and thinnest point (Amctpost), total corneal volume (Vtotal) and volumetric progression for each 0.05 mm step of the radius value centred to the thinnest point (VOLMCT) and anterior/posterior apex (VOLAAP/VOLPAP) comprised the morphogeometric/volumetric parameters. In the DS group, 58.1% of the eyes presented abnormal topography. High-order and coma aberrations, asphericity, Dapexant, Aant, Apost and Aapexant were significantly higher, whereas CCT, Aapexpost, Amctpost, Vtotal, VOLAAP, VOLPAP and VOLMCT were lower in the DS group than in the control group (p < 0.05). Dapexpost did not differ between the groups (p > 0.05). This study demonstrates that corneas of the subjects with DS are different and more aberrated than those of normal age- and sex-matched non-DS controls. Anterior corneal apex appears to be displaced in DS even with normal topography, while posterior apex seems stable although topography is abnormal. These findings may help to modify our approach in the diagnosis of keratopathy in subjects with DS.
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Affiliation(s)
- Ibrahim Toprak
- Department of Research and Development, VISSUM, 03016 Alicante, Spain; (I.T.); (A.V.); (J.L.A.d.B.)
- Department of Ophthalmology, Faculty of Medicine, Pamukkale University, Denizli 20160, Turkey
| | - Francisco Cavas
- Department of Structures, Construction and Graphical Expression, Technical University of Cartagena, 30202 Cartagena, Spain;
- Correspondence: ; Tel.: +34-968-338-856
| | - Alfredo Vega
- Department of Research and Development, VISSUM, 03016 Alicante, Spain; (I.T.); (A.V.); (J.L.A.d.B.)
- Cornea, Cataract and Refractive Surgery Department, VISSUM, 03016 Alicante, Spain;
- Division of Ophthalmology, Department of Pathology and Surgery, Faculty of Medicine, Miguel Hernández University, 03016 Alicante, Spain
| | - José S. Velázquez
- Department of Structures, Construction and Graphical Expression, Technical University of Cartagena, 30202 Cartagena, Spain;
| | - Jorge L. Alio del Barrio
- Department of Research and Development, VISSUM, 03016 Alicante, Spain; (I.T.); (A.V.); (J.L.A.d.B.)
- Cornea, Cataract and Refractive Surgery Department, VISSUM, 03016 Alicante, Spain;
- Division of Ophthalmology, Department of Pathology and Surgery, Faculty of Medicine, Miguel Hernández University, 03016 Alicante, Spain
| | - Jorge L. Alio
- Cornea, Cataract and Refractive Surgery Department, VISSUM, 03016 Alicante, Spain;
- Division of Ophthalmology, Department of Pathology and Surgery, Faculty of Medicine, Miguel Hernández University, 03016 Alicante, Spain
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Relationship between Corneal Morphogeometrical Properties and Biomechanical Parameters Derived from Dynamic Bidirectional Air Applanation Measurement Procedure in Keratoconus. Diagnostics (Basel) 2020; 10:diagnostics10090640. [PMID: 32867063 PMCID: PMC7555946 DOI: 10.3390/diagnostics10090640] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/25/2020] [Accepted: 08/25/2020] [Indexed: 02/07/2023] Open
Abstract
The morphogeometric analysis of the corneal structure has become a clinically relevant diagnostic procedure in keratoconus (KC) as well as the in vivo evaluation of the corneal biomechanical properties. However, the relationship between these two types of metrics is still not well understood. The current study investigated the relationship of corneal morphogeometry and volume with two biomechanical parameters: corneal hysteresis (CH) and corneal resistance factor (CRF), both provided by an Ocular Response Analyzer (Reichert). It included 109 eyes from 109 patients (aged between 18 and 69 years) with a diagnosis of keratoconus (KC) who underwent a complete eye examination including a comprehensive corneal topographic analysis with the Sirius system (CSO). With the topographic information obtained, a morphogeometric and volumetric analysis was performed, defining different variables of clinical use. CH and CRF were found to be correlated with these variables, but this correlation was highly influenced by corneal thickness. This suggests that the mechanical properties of KC cornea contribute only in a partial and limited manner to these biomechanical parameters, being mostly influenced by morphogeometry under normal intraocular pressure levels. This would explain the limitation of CH and CRF as diagnostic tools for the detection of incipient cases of KC.
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