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Meek KM, Knupp C, Lewis PN, Morgan SR, Hayes S. Structural control of corneal transparency, refractive power and dynamics. Eye (Lond) 2024:10.1038/s41433-024-02969-7. [PMID: 38396030 DOI: 10.1038/s41433-024-02969-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 12/11/2023] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
The cornea needs to be transparent to visible light and precisely curved to provide the correct refractive power. Both properties are governed by its structure. Corneal transparency arises from constructive interference of visible light due to the relatively ordered arrangement of collagen fibrils in the corneal stroma. The arrangement is controlled by the negatively charged proteoglycans surrounding the fibrils. Small changes in fibril organisation can be tolerated but larger changes cause light scattering. Corneal keratocytes do not scatter light because their refractive index matches that of the surrounding matrix. When activated, however, they become fibroblasts that have a lower refractive index. Modelling shows that this change in refractive index significantly increases light scatter. At the microscopic level, the corneal stroma has a lamellar structure, the parallel collagen fibrils within each lamella making a large angle with those of adjacent lamellae. X-ray scattering has shown that the lamellae have preferred orientations in the human cornea: inferior-superior and nasal-temporal in the central cornea and circumferential at the limbus. The directions at the centre of the cornea may help withstand the pull of the extraocular muscles whereas the pseudo-circular arrangement at the limbus supports the change in curvature between the cornea and sclera. Elastic fibres are also present; in the limbus they contain fibrillin microfibrils surrounding an elastin core, whereas at the centre of the cornea, they exist as thin bundles of fibrillin-rich microfibrils. We present a model based on the structure described above that may explain how the cornea withstands repeated pressure changes due to the ocular pulse.
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Affiliation(s)
- Keith M Meek
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK.
| | - Carlo Knupp
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Philip N Lewis
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Siân R Morgan
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Sally Hayes
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4HQ, UK
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2
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Braidotti N, do R. B. F. Lima MA, Zanetti M, Rubert A, Ciubotaru C, Lazzarino M, Sbaizero O, Cojoc D. The Role of Cytoskeleton Revealed by Quartz Crystal Microbalance and Digital Holographic Microscopy. Int J Mol Sci 2022; 23:ijms23084108. [PMID: 35456926 PMCID: PMC9029771 DOI: 10.3390/ijms23084108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 03/30/2022] [Accepted: 04/06/2022] [Indexed: 01/27/2023] Open
Abstract
The connection between cytoskeleton alterations and diseases is well known and has stimulated research on cell mechanics, aiming to develop reliable biomarkers. In this study, we present results on rheological, adhesion, and morphological properties of primary rat cardiac fibroblasts, the cytoskeleton of which was altered by treatment with cytochalasin D (Cyt-D) and nocodazole (Noc), respectively. We used two complementary techniques: quartz crystal microbalance (QCM) and digital holographic microscopy (DHM). Qualitative data on cell viscoelasticity and adhesion changes at the cell–substrate near-interface layer were obtained with QCM, while DHM allowed the measurement of morphological changes due to the cytoskeletal alterations. A rapid effect of Cyt-D was observed, leading to a reduction in cell viscosity, loss of adhesion, and cell rounding, often followed by detachment from the surface. Noc treatment, instead, induced slower but continuous variations in the rheological behavior for four hours of treatment. The higher vibrational energy dissipation reflected the cell’s ability to maintain a stable attachment to the substrate, while a cytoskeletal rearrangement occurs. In fact, along with the complete disaggregation of microtubules at prolonged drug exposure, a compensatory effect of actin polymerization emerged, with increased stress fiber formation.
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Affiliation(s)
- Nicoletta Braidotti
- Department of Physics, University of Trieste, Via A. Valerio 2, 34127 Trieste, Italy; (N.B.); (M.A.d.R.B.F.L.); (M.Z.)
- Consiglio Nazionale delle Ricerche (CNR), Istituto Officina dei Materiali (IOM), Area Science Park-Basovizza, Strada Statale 14, Km 163,5, 34149 Trieste, Italy; (C.C.); (M.L.); (D.C.)
| | - Maria Augusta do R. B. F. Lima
- Department of Physics, University of Trieste, Via A. Valerio 2, 34127 Trieste, Italy; (N.B.); (M.A.d.R.B.F.L.); (M.Z.)
- Consiglio Nazionale delle Ricerche (CNR), Istituto Officina dei Materiali (IOM), Area Science Park-Basovizza, Strada Statale 14, Km 163,5, 34149 Trieste, Italy; (C.C.); (M.L.); (D.C.)
| | - Michele Zanetti
- Department of Physics, University of Trieste, Via A. Valerio 2, 34127 Trieste, Italy; (N.B.); (M.A.d.R.B.F.L.); (M.Z.)
- Consiglio Nazionale delle Ricerche (CNR), Istituto Officina dei Materiali (IOM), Area Science Park-Basovizza, Strada Statale 14, Km 163,5, 34149 Trieste, Italy; (C.C.); (M.L.); (D.C.)
| | - Alessandro Rubert
- Department of Engineering and Architecture, University of Trieste, Via A. Valerio 6/A, 34127 Trieste, Italy;
| | - Catalin Ciubotaru
- Consiglio Nazionale delle Ricerche (CNR), Istituto Officina dei Materiali (IOM), Area Science Park-Basovizza, Strada Statale 14, Km 163,5, 34149 Trieste, Italy; (C.C.); (M.L.); (D.C.)
| | - Marco Lazzarino
- Consiglio Nazionale delle Ricerche (CNR), Istituto Officina dei Materiali (IOM), Area Science Park-Basovizza, Strada Statale 14, Km 163,5, 34149 Trieste, Italy; (C.C.); (M.L.); (D.C.)
| | - Orfeo Sbaizero
- Department of Engineering and Architecture, University of Trieste, Via A. Valerio 6/A, 34127 Trieste, Italy;
- Correspondence:
| | - Dan Cojoc
- Consiglio Nazionale delle Ricerche (CNR), Istituto Officina dei Materiali (IOM), Area Science Park-Basovizza, Strada Statale 14, Km 163,5, 34149 Trieste, Italy; (C.C.); (M.L.); (D.C.)
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3
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Gupta S, Buyank F, Sinha NR, Grant DG, Sinha PR, Iozzo RV, Chaurasia SS, Mohan RR. Decorin regulates collagen fibrillogenesis during corneal wound healing in mouse in vivo. Exp Eye Res 2022; 216:108933. [PMID: 35031282 PMCID: PMC8885890 DOI: 10.1016/j.exer.2022.108933] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/14/2021] [Accepted: 01/05/2022] [Indexed: 12/22/2022]
Abstract
A characteristic rigid spatial arrangement of collagen fibrils in the stroma is critical for corneal transparency. This unique organization of collagen fibrils in corneal stroma can be impacted by the presence and interactions of proteoglycans and extracellular matrix (ECM) proteins in a corneal microenvironment. Earlier studies revealed that decorin, a leucine-rich proteoglycan in stroma, regulates keratocyte-collagen matrix assembly and wound healing in the cornea. This study investigated the role of decorin in the regulation of stromal fibrillogenesis and corneal transparency in vivo employing a loss-of-function genetic approach using decorin null (dcn-/-) and wild type (dcn+/+) mice and a standard alkali-injury model. A time-dependent ocular examinations with Slit lamp microscope in live animals assessed corneal clarity, haze, and neovascularization levels in normal and injured eyes. Morphometric changes in normal and injured dcn+/+ and dcn-/- corneas, post-euthanasia, were analyzed with Masson's Trichrome and Periodic Acid-Schiff (PAS) histology evaluations. The ultrastructure changes in all corneas were investigated with transmission electron microscopy (TEM). Injury to eye produced clinically relevant corneal haze and neovascularization in dcn-/- and dcn+/+ mice while corneas of uninjured eyes remained clear and avascular. A clinically significant haze and neovascularization appeared in injured dcn-/- corneas compared to the dcn+/+ corneas at day 21 post-injury and not at early tested times. Histological examinations revealed noticeably abnormal morphology and compromised collagen levels in injured dcn-/- corneas compared to the injured/normal dcn+/+ and uninjured dcn-/- corneas. TEM analysis exhibited remarkably uneven collagen fibrils size and distribution in the stroma with asymmetrical organization and loose packing in injured dcn-/- corneas than injured/normal dcn+/+ and uninjured dcn-/- corneas. The minimum and maximum inter-fibril distances were markedly irregular in injured dcn-/- corneas compared to all other corneas. Together, results of clinical, histological, and ultrastructural investigations in a genetic knockout model suggested that decorin influenced stromal fibrillogenesis and transparency in healing cornea.
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Affiliation(s)
- Suneel Gupta
- Harry S. Truman Memorial Veterans’ Hospital, Columbia, Missouri, USA.,Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Filiz Buyank
- Department of Computer Science, University of Missouri, Columbia, Missouri, USA
| | - Nihant R. Sinha
- Harry S. Truman Memorial Veterans’ Hospital, Columbia, Missouri, USA.,Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - DeAna G. Grant
- Electron Microscopy Core, University of Missouri, Columbia, Missouri, USA
| | - Prashant R. Sinha
- Harry S. Truman Memorial Veterans’ Hospital, Columbia, Missouri, USA.,Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Renato V. Iozzo
- Department of Pathology, Anatomy, and Cell Biology, and Translational Cellular Oncology Program, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Shyam S. Chaurasia
- Harry S. Truman Memorial Veterans’ Hospital, Columbia, Missouri, USA.,Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Rajiv R. Mohan
- Harry S. Truman Memorial Veterans’ Hospital, Columbia, Missouri, USA.,Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.,Mason Eye Institute, School of Medicine, University of Missouri, Columbia, Missouri, USA.,Corresponding author: Rajiv R. Mohan, MS, PhD, FARVO, Professor of Ophthalmology & Molecular Medicine, University of Missouri, 1600 E. Rollins Rd, Columbia, MO 65211,
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Hayes S, Aldahlawi N, Marcovich AL, Brekelmans J, Goz A, Scherz A, Young RD, Bell JS, O'Brart DP, Nuijts RMMA, Meek KM. The effect of bacteriochlorophyll derivative WST-D and near infrared light on the molecular and fibrillar architecture of the corneal stroma. Sci Rep 2020; 10:9836. [PMID: 32555309 PMCID: PMC7299946 DOI: 10.1038/s41598-020-66869-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/28/2020] [Indexed: 11/30/2022] Open
Abstract
A cross-linking technique involving application of Bacteriochlorophyll Derivative WST-11 mixed with dextran (WST-D) to the epithelium-debrided cornea and illumination with Near Infrared (NIR), has been identified as a promising therapy for stiffening pathologically weakened corneas. To investigate its effect on corneal collagen architecture, x-ray scattering and electron microscopy data were collected from paired WST-D/NIR treated and untreated rabbit corneas. The treated eye received 2.5 mg/mL WST-D and was illuminated by a NIR diode laser (755 nm, 10 mW/cm2). An increase in corneal thickness (caused by corneal oedema) occurred at 1-day post-treatment but resolved in the majority of cases within 4 days. The epithelium was fully healed after 6–8 days. X-ray scattering revealed no difference in average collagen interfibrillar spacing, fibril diameter, D-periodicity or intermolecular spacing between treated and untreated specimens. Similarly, electron microscopy images of the anterior and posterior stroma in healed WST-D/NIR corneas and untreated controls revealed no obvious differences in collagen organisation or fibril diameter. As the size and organisation of stromal collagen is closely associated with the optical properties of the cornea, the absence of any large-scale changes following treatment confirms the potential of WST-D/NIR therapy as a means of safely stiffening the cornea.
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Affiliation(s)
- S Hayes
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
| | - N Aldahlawi
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - A L Marcovich
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel.,Department of Ophthalmology, Kaplan Medical Center, Rehovot, Israel
| | - J Brekelmans
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel.,University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands
| | - A Goz
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel.,Department of Ophthalmology, Kaplan Medical Center, Rehovot, Israel
| | - A Scherz
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - R D Young
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - J S Bell
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - D P O'Brart
- Keratoconus Research Institute, Department of Ophthalmology, St Thomas Hospital, London, United Kingdom
| | - R M M A Nuijts
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands
| | - K M Meek
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
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Alzahrani K, Mofty H, Lin EYC, Carley F, Brahma A, Morley D, Biswas S, Hillarby MC. Corneal Imaging and Densitometry Measurements in Juvenile and Adult Keratoconus Patients to Evaluate Disease Progression and Treatment Effects After Corneal Cross-Linking. CLINICAL OPTOMETRY 2019; 11:173-180. [PMID: 31920417 PMCID: PMC6941694 DOI: 10.2147/opto.s226000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
PURPOSE In this study densitometry software for the Oculus Pentacam was used to investigate the treatment outcomes of corneal cross linking (CXL) in adult and juvenile keratoconus (KCN) patients. Densitometry measurements were taken before and after treatment and followed up for one year. METHODS A comparative study was carried out at Manchester Royal Eye Hospital. Corneal densitometry measurements collected before and after CXL treatment for 32 eyes from KC patients, aged between 12 and 39, were divided to 2 groups 13-18 years (juvenile group) and 19-39 years (adult group) and analysed and compared to pre and post treatment at 3, 6 and 12 months for each group and between both groups. RESULTS Analysis of densitometry measurements found higher corneal densitometry after CXL which peaks at three months post treatment in both groups. There was significant diversity in corneal densitometry measurements in the stromal zone 0-2 and 2-6 mm for all layers except the posterior layer for both groups (P<0.05). Significantly increased densitometry value was found higher in the juvenile group at six months in the central (P=0.006) and posterior (P=0.004) layers for zone 0-2 mm. The same layers differed significantly also in the 2-6 mm zone in all layers (P=0.01). One year post treatment the same significant increased densitometry level was seen in the juvenile group in the 0-2 mm zone of the central (P=0.007) and posterior layers (P=0.01), as was the 2-6 mm zone (P=0.04). However, no significant difference was found between pre and post treatment for best corrected visual acuity (BCVA), central corneal thickness (CCT) and thinnest area between both groups. A significant difference was found between pre and post treatment for best corrected visual acuity (BCVA), in the adult group at 6 and 12 months post-treatment from pre-treatment (P=0.02, P=0.16) respectively. CONCLUSION Corneal clarity post CXL treatment in the juvenile group differed significantly from the adult group. Both groups showed increased haze at 3 months post treatment but the adults showed improvement over the next 9 months. In contrast, the juvenile group showed higher densitometry readings at both 6 and 12 months post treatment in comparison to adult group. The reasons for this remain unclear.
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Affiliation(s)
- Khaled Alzahrani
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Manchester, UK
- Research Department, Manchester Royal Eye Hospital, Manchester, UK
- King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | - Hanan Mofty
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Manchester, UK
- Optometry Department, College of Applied Medical Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Emily YC Lin
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Manchester, UK
| | - Fiona Carley
- Research Department, Manchester Royal Eye Hospital, Manchester, UK
| | - Arun Brahma
- Research Department, Manchester Royal Eye Hospital, Manchester, UK
| | - Debbie Morley
- Research Department, Manchester Royal Eye Hospital, Manchester, UK
| | - Susmito Biswas
- Research Department, Manchester Royal Eye Hospital, Manchester, UK
| | - M Chantal Hillarby
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Manchester, UK
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Hayes S, White T, Boote C, Kamma-Lorger CS, Bell J, Sorenson T, Terrill N, Shebanova O, Meek KM. The structural response of the cornea to changes in stromal hydration. J R Soc Interface 2018; 14:rsif.2017.0062. [PMID: 28592658 PMCID: PMC5493790 DOI: 10.1098/rsif.2017.0062] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/12/2017] [Indexed: 11/12/2022] Open
Abstract
The primary aim of this study was to quantify the relationship between corneal structure and hydration in humans and pigs. X-ray scattering data were collected from human and porcine corneas equilibrated with polyethylene glycol (PEG) to varying levels of hydration, to obtain measurements of collagen fibril diameter, interfibrillar spacing (IFS) and intermolecular spacing. Both species showed a strong positive linear correlation between hydration and IFS2 and a nonlinear, bi-phasic relationship between hydration and fibril diameter, whereby fibril diameter increased up to approximately physiological hydration, H = 3.0, with little change thereafter. Above H = 3.0, porcine corneas exhibited a larger fibril diameter than human corneas (p < 0.001). Intermolecular spacing also varied with hydration in a bi-phasic manner but reached a maximum value at a lower hydration (H = 1.5) than fibril diameter. Human corneas displayed a higher intermolecular spacing than porcine corneas at all hydrations (p < 0.0001). Human and porcine corneas required a similar PEG concentration to reach physiological hydration, suggesting that the total fixed charge that gives rise to the swelling pressure is the same. The difference in their structural responses to hydration can be explained by variations in molecular cross-linking and intra/interfibrillar water partitioning.
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Affiliation(s)
- Sally Hayes
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Tomas White
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Craig Boote
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Christina S Kamma-Lorger
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.,ALBA Synchrotron Light Source, Cerdanyola del Vallès, Barcelona, Spain
| | - James Bell
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | | | | | | | - Keith M Meek
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
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MOSHIRFAR M, DESAUTELS JD, WALKER BD, MURRI MS, BIRDSONG OC, HOOPES PCS. Mechanisms of Optical Regression Following Corneal Laser Refractive Surgery: Epithelial and Stromal Responses. MEDICAL HYPOTHESIS, DISCOVERY & INNOVATION OPHTHALMOLOGY JOURNAL 2018; 7:1-9. [PMID: 29644238 PMCID: PMC5887600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Laser vision correction is a safe and effective method of reducing spectacle dependence. Photorefractive Keratectomy (PRK), Laser In Situ Keratomileusis (LASIK), and Small-Incision Lenticule Extraction (SMILE) can accurately correct myopia, hyperopia, and astigmatism. Although these procedures are nearing optimization in terms of their ability to produce a desired refractive target, the long term cellular responses of the cornea to these procedures can cause patients to regress from the their ideal postoperative refraction. In many cases, refractive regression requires follow up enhancement surgeries, presenting additional risks to patients. Although some risk factors underlying refractive regression have been identified, the exact mechanisms have not been elucidated. It is clear that cellular proliferation events are important mediators of optical regression. This review focused specifically on cellular changes to the corneal epithelium and stroma, which may influence postoperative visual regression following LASIK, PRK, and SMILE procedures.
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Affiliation(s)
- Majid MOSHIRFAR
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, 50 North Medical Dr., Salt Lake City, UT 84132, United States,HDR Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT 84020, United States
| | - Jordan D. DESAUTELS
- HDR Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT 84020, United States,The Warren Alpert Medical School of Brown University, Providence, RI 02903, United States
| | - Brian D. WALKER
- McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin St, Houston, TX 77030, United States
| | - Michael S. MURRI
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, 50 North Medical Dr., Salt Lake City, UT 84132, United States
| | - Orry C. BIRDSONG
- HDR Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT 84020, United States
| | - Phillip C. Sr HOOPES
- HDR Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT 84020, United States
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Mofty H, Alzahrani K, Carley F, Harper S, Brahma A, Au L, Morley D, Hillarby MC. Evaluation of corneal symmetry after UV corneal crosslinking for keratoconus. Clin Ophthalmol 2017; 11:2043-2049. [PMID: 29200817 PMCID: PMC5700762 DOI: 10.2147/opth.s143511] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to assess UV corneal crosslinking (CXL) treatment outcomes for keratoconus by evaluating the corneal regularity in patients through follow-up using the Oculus Pentacam. Patients and methods A total of 18 eyes from CXL patients with keratoconus were studied before and after CXL treatment, and six eyes from six patients who were not treated with CXL served as controls. Treated patients had Pentacam images taken before CXL treatment and regularly 3 months post treatment up to the 12th month. Controls were imaged during their first appointment and after 12 months. Symmetry and asphericity were evaluated and correlated with both best-corrected visual acuity (BCVA) and maximum K-readings. Results In the CXL-treated group, there was a significant improvement in the index of symmetrical variation (ISV) and keratoconus index (KI) at 3 months and in the index of height asymmetry (IHA) and minimum radius of curvature (Rmin) at 9 months post treatment. On the contrary, the untreated group’s indices showed some significant worsening in ISV, KI, central keratoconus index (CKI), and Rmin. A novel finding in our study was a slight positive shift of anterior asphericity in the 6 mm, 7 mm, and 8 mm 3 months after treatment, which had a correlation with BCVA (R2=0.390, p=0.053) and a strong correlation with maximum K-reading (R2=0.690, p=0.005). However, the untreated group had no significant changes after 1 year. Conclusion The corneal asymmetrical shape is associated with the spherical aberration alteration influenced by temporal evolution of surface ablation and increased corneal haze. However, insignificant changes in symmetry attest the stabilization effect on cornea postoperatively as compared with controls.
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Affiliation(s)
- Hanan Mofty
- Optometry Department, College of Applied Medical Science, King Saud University, Riyadh, Kingdom of Saudi Arabia.,Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester
| | - Khaled Alzahrani
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester
| | | | | | - Arun Brahma
- Manchester Royal Eye Hospital, Manchester, UK
| | - Leon Au
- Manchester Royal Eye Hospital, Manchester, UK
| | | | - M Chantal Hillarby
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester
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Cardoso Dos Santos M, Déturche R, Vézy C, Jaffiol R. Topography of Cells Revealed by Variable-Angle Total Internal Reflection Fluorescence Microscopy. Biophys J 2017; 111:1316-1327. [PMID: 27653490 DOI: 10.1016/j.bpj.2016.06.043] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/24/2016] [Accepted: 06/28/2016] [Indexed: 11/17/2022] Open
Abstract
We propose an improved version of variable-angle total internal reflection fluorescence microscopy (vaTIRFM) adapted to modern TIRF setup. This technique involves the recording of a stack of TIRF images, by gradually increasing the incident angle of the light beam on the sample. A comprehensive theory was developed to extract the membrane/substrate separation distance from fluorescently labeled cell membranes. A straightforward image processing was then established to compute the topography of cells with a nanometric axial resolution, typically 10-20 nm. To highlight the new opportunities offered by vaTIRFM to quantify adhesion process of motile cells, adhesion of MDA-MB-231 cancer cells on glass substrate coated with fibronectin was examined.
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Affiliation(s)
- Marcelina Cardoso Dos Santos
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France
| | - Régis Déturche
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France
| | - Cyrille Vézy
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France
| | - Rodolphe Jaffiol
- Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay - UMR 6281 Centre National de la Recherche Scientifique, Université de Technologie de Troyes, Troyes, France.
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