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Jiang D, Grainger DW, Weiss JA, Timmins LH. Integration of Febio as an Instructional Tool in the Undergraduate Biomechanics Curriculum. J Biomech Eng 2024; 146:051001. [PMID: 38441207 PMCID: PMC11005855 DOI: 10.1115/1.4064990] [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: 09/25/2023] [Revised: 02/21/2024] [Indexed: 03/20/2024]
Abstract
Computer simulations play an important role in a range of biomedical engineering applications. Thus, it is important that biomedical engineering students engage with modeling in their undergraduate education and establish an understanding of its practice. In addition, computational tools enhance active learning and complement standard pedagogical approaches to promote student understanding of course content. Herein, we describe the development and implementation of learning modules for computational modeling and simulation (CM&S) within an undergraduate biomechanics course. We developed four CM&S learning modules that targeted predefined course goals and learning outcomes within the febio studio software. For each module, students were guided through CM&S tutorials and tasked to construct and analyze more advanced models to assess learning and competency and evaluate module effectiveness. Results showed that students demonstrated an increased interest in CM&S through module progression and that modules promoted the understanding of course content. In addition, students exhibited increased understanding and competency in finite element model development and simulation software use. Lastly, it was evident that students recognized the importance of coupling theory, experiments, and modeling and understood the importance of CM&S in biomedical engineering and its broad application. Our findings suggest that integrating well-designed CM&S modules into undergraduate biomedical engineering education holds much promise in supporting student learning experiences and introducing students to modern engineering tools relevant to professional development.
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Affiliation(s)
- David Jiang
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112; School of Engineering Medicine, Texas A&M University, Houston, TX 77843; EnMed Tower, 1020 Holcombe Blvd, Houston, TX 77030
| | - David W. Grainger
- Department of Biomedical Engineering, University of Utah, 36 S. Wasatch Drive, SMBB 3100, Salt Lake City, UT 84112; Department of Molecular Pharmaceutics, University of Utah, Salt Lake City, UT 84112
- University of Utah
| | - Jeffrey A. Weiss
- ASME Fellow Department of Biomedical Engineering, University of Utah, 36 S. Wasatch Drive, SMBB 3100, Salt Lake City, UT 84112; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT 84112; Department of Orthopedics, University of Utah, Salt Lake City, UT 84112
| | - Lucas H. Timmins
- School of Engineering Medicine, Texas A&M University, Houston, TX 77030; Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843; Department of Multidisciplinary Engineering, Texas A&M University, College Station, TX 77843; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112;Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT 84112;EnMed Tower, 1020 Holcombe Blvd, Houston, TX 77030
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Jiravarnsirikul A, Yang H, Jeoung JW, Hong SW, Rezapour J, Gardiner S, Fortune B, Girard MJA, Nicolela M, Zangwill LM, Chauhan BC, Burgoyne CF. OCT Optic Nerve Head Morphology in Myopia IV: Neural Canal Scleral Flange Remodeling in Highly Myopic Eyes. Am J Ophthalmol 2024; 261:141-164. [PMID: 38311154 PMCID: PMC11031338 DOI: 10.1016/j.ajo.2024.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/16/2024] [Accepted: 01/21/2024] [Indexed: 02/10/2024]
Abstract
PURPOSE To compare the prevalence, location and magnitude of optic nerve head (ONH) OCT-detected, exposed neural canal (ENC), externally oblique choroidal border tissue (EOCBT) and exposed scleral flange (ESF) regions in 122 highly myopic (Hi-Myo) versus 362 nonhighly myopic healthy (Non-Hi-Myo-Healthy) eyes. DESIGN Cross-sectional study. METHODS After OCT radial B-scan, ONH imaging, Bruch's membrane opening (BMO), the anterior scleral canal opening (ASCO), and the scleral flange opening (SFO) were manually segmented in each B-scan and projected to BMO reference plane. The direction and magnitude of BMO/ASCO offset and BMO/SFO offset as well as the location and magnitude of ENC, EOCBT and ESF regions, perineural canal (pNC) retinal nerve fiber layer thickness (RNFLT) and pNC choroidal thickness (CT) were calculated within 30° sectors relative to the Foveal-BMO (FoBMO) axis. Hi-ESF eyes were defined to be those with an ESF region ≥100 µms in at least 1 sector. RESULTS Hi-Myo eyes more frequently demonstrated Hi-ESF regions (87/122) than Non-Hi-myo-Healthy eyes (73/362) and contained significantly larger ENC, EOCBT, and ESF regions (P < .001) which were greatest in magnitude and prevalence within the inferior-temporal FoBMO sectors where Hi-Myo pNC-RNFLT and pNCCT were thinnest. BMO/ASCO offset and the BMO/SFO offset were both significantly increased (P < .001) in the Hi-Myo eyes, with the latter demonstrating a greater increase. CONCLUSIONS ENC region tissue remodeling that includes the scleral flange is enhanced in Hi-Myo compared to Non-Hi-Myo-Healthy eyes. Longitudinal studies are necessary to determine whether the presence of an ENC region influences ONH susceptibility to aging and/or glaucoma.
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Affiliation(s)
- Anuwat Jiravarnsirikul
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory (A.J., H.Y., C.F.B.), Legacy Research Institute, Portland, Oregon, USA; Department of Ophthalmology (A.J.), Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Hongli Yang
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory (A.J., H.Y., C.F.B.), Legacy Research Institute, Portland, Oregon, USA
| | - Jin Wook Jeoung
- Department of Ophthalmology (J.W.J.), Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | | | - Jasmin Rezapour
- Viterbi Family Department of Ophthalmology (J.R., L.Z.), Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California, USA; Department of Ophthalmology (J.R.), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stuart Gardiner
- Devers Eye Institute, Discoveries in Sight Research Laboratories (S.G., B.F.), Legacy Research Institute, Portland, Oregon, USA
| | - Brad Fortune
- Devers Eye Institute, Discoveries in Sight Research Laboratories (S.G., B.F.), Legacy Research Institute, Portland, Oregon, USA
| | - Michaël J A Girard
- Department of Biomedical Engineering (M.J.A.G.), Ophthalmic Engineering & Innovation Laboratory, National University of Singapore, Singapore, Singapore
| | - Marcelo Nicolela
- Ophthalmology and Visual Sciences (M.N., B.C.C.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Linda M Zangwill
- Viterbi Family Department of Ophthalmology (J.R., L.Z.), Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, California, USA
| | - Balwantray C Chauhan
- Ophthalmology and Visual Sciences (M.N., B.C.C.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Claude F Burgoyne
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory (A.J., H.Y., C.F.B.), Legacy Research Institute, Portland, Oregon, USA.
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Chuangsuwanich T, Tun TA, Braeu FA, Wang X, Chin ZY, Panda SK, Buist M, Milea D, Strouthidis N, Perera S, Nongpiur ME, Aung T, Girard MJA. Adduction induces large optic nerve head deformations in subjects with normal-tension glaucoma. Br J Ophthalmol 2024; 108:522-529. [PMID: 37011991 DOI: 10.1136/bjo-2022-322461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 03/15/2023] [Indexed: 04/05/2023]
Abstract
PURPOSE To assess intraocular pressure (IOP)-induced and gaze-induced optic nerve head (ONH) strains in subjects with high-tension glaucoma (HTG) and normal-tension glaucoma (NTG). DESIGN Clinic-based cross-sectional study. METHODS The ONH from one eye of 228 subjects (114 subjects with HTG (pre-treatment IOP≥21 mm Hg) and 114 with NTG (pre-treatment IOP<21 mm Hg)) was imaged with optical coherence tomography (OCT) under the following conditions: (1) OCT primary gaze, (2) 20° adduction from OCT primary gaze, (3) 20° abduction from OCT primary gaze and (4) OCT primary gaze with acute IOP elevation (to approximately 33 mm Hg). We then performed digital volume correlation analysis to quantify IOP-induced and gaze-induced ONH tissue deformations and strains. RESULTS Across all subjects, adduction generated high effective strain (4.4%±2.3%) in the LC tissue with no significant difference (p>0.05) with those induced by IOP elevation (4.5%±2.4%); while abduction generated significantly lower (p=0.01) effective strain (3.1%±1.9%). The lamina cribrosa (LC) of HTG subjects exhibited significantly higher effective strain than those of NTG subjects under IOP elevation (HTG: 4.6%±1.7% vs NTG: 4.1%±1.5%, p<0.05). Conversely, the LC of NTG subjects exhibited significantly higher effective strain than those of HTG subjects under adduction (NTG: 4.9%±1.9% vs HTG: 4.0%±1.4%, p<0.05). CONCLUSION We found that NTG subjects experienced higher strains due to adduction than HTG subjects, while HTG subjects experienced higher strain due to IOP elevation than NTG subjects-and that these differences were most pronounced in the LC tissue.
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Affiliation(s)
- Thanadet Chuangsuwanich
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Tin A Tun
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Duke-NUS Medical School, Singapore
| | - Fabian A Braeu
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Singapore-MIT Alliance for Research and Technology, Singapore
| | - Xiaofei Wang
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Zhi Yun Chin
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
| | - Satish K Panda
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore
| | - Martin Buist
- Department of Biomedical Engineering, National University of Singapore, Singapore
| | - Dan Milea
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Duke-NUS Medical School, Singapore
| | | | - Shamira Perera
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Duke-NUS Medical School, Singapore
| | - Monisha Esther Nongpiur
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Duke-NUS Medical School, Singapore
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Duke-NUS Medical School, Singapore
| | - Michael J A Girard
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
- Duke-NUS Medical School, Singapore
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Hong S, Yang H, Gardiner SK, Luo H, Sharpe GP, Caprioli J, Demirel S, Girkin CA, Mardin CY, Quigley HA, Scheuerle AF, Fortune B, Jiravarnsirikul A, Zangalli C, Chauhan BC, Burgoyne CF. Optical Coherence Tomographic Optic Nerve Head Morphology in Myopia III: The Exposed Neural Canal Region in Healthy Eyes-Implications for High Myopia. Am J Ophthalmol 2024; 258:55-75. [PMID: 37673378 PMCID: PMC10841091 DOI: 10.1016/j.ajo.2023.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/04/2023] [Accepted: 08/17/2023] [Indexed: 09/08/2023]
Abstract
PURPOSE To determine the prevalence and magnitude of optical coherence tomography (OCT) exposed neural canal (ENC), externally oblique choroidal border tissue (EOCBT), and exposed scleral flange (ESF) regions in 362 non-highly myopic (spherical equivalent -6.00 to 5.75 diopters) eyes of 362 healthy subjects. DESIGN Cross-sectional study. METHODS After OCT optic nerve head (ONH) imaging, Bruch membrane opening (BMO), the anterior scleral canal opening (ASCO), and the scleral flange opening (SFO) were manually segmented. BMO, ASCO, and SFO points were projected to the BMO reference plane. The direction and magnitude of BMO/ASCO offset as well as the magnitude of ENC, EOCBT, and ESF was calculated within 30° sectors relative to the foveal-BMO axis. Hi-ESF eyes demonstrated an ESF ≥100 µm in at least 1 sector. Sectoral peri-neural canal choroidal thickness (pNC-CT) was measured and correlations between the magnitude of sectoral ESF and proportional pNC-CT were assessed. RESULTS Seventy-three Hi-ESF (20.2%) and 289 non-Hi-ESF eyes (79.8%) were identified. BMO/ASCO offset as well as ENC, EOCBT, and ESF prevalence and magnitude were greatest inferior temporally where the pNC-CT was thinnest. Among Hi-ESF eyes, the magnitude of each ENC region correlated with the BMO/ASCO offset magnitude, and the sectors with the longest ESF correlated with the sectors with proportionally thinnest pNC-CT. CONCLUSIONS ONH BMO/ASCO offset, either as a cause or result of ONH neural canal remodeling, corresponds with the sectoral location of maximum ESF and minimum pNC-CT in non-highly myopic eyes. Longitudinal studies to characterize the development and clinical implications of ENC Hi-ESF regions in non-highly myopic and highly myopic eyes are indicated.
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Affiliation(s)
- Seungwoo Hong
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory, Legacy Research Institute (S.H., H.Y., H.L., A.J., C.F.B.), Portland, Oregon, USA; Yebon Eye Clinic (S.H.), Seoul, Korea
| | - Hongli Yang
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory, Legacy Research Institute (S.H., H.Y., H.L., A.J., C.F.B.), Portland, Oregon, USA
| | - Stuart K Gardiner
- Devers Eye Institute, Discoveries in Sight Research Laboratories, Legacy Research Institute (S.K.G., S.D., B.F.), Portland, Oregon, USA
| | - Haomin Luo
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory, Legacy Research Institute (S.H., H.Y., H.L., A.J., C.F.B.), Portland, Oregon, USA; Department of Ophthalmology, Hunan Provincial People's Hospital, Hunan Normal University (H.L.), Changsha, Hunan Province, China
| | - Glen P Sharpe
- Ophthalmology and Visual Sciences, Dalhousie University (G.P.S., B.C.C.), Halifax, Nova Scotia, Canada
| | - Joseph Caprioli
- Jules Stein Eye Institute, David Geffen School of Medicine at UCLA (J.C.), Los Angeles, California, USA
| | - Shaban Demirel
- Devers Eye Institute, Discoveries in Sight Research Laboratories, Legacy Research Institute (S.K.G., S.D., B.F.), Portland, Oregon, USA
| | - Christopher A Girkin
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham (C.A.G.), Birmingham, Alabama, USA
| | - Christian Y Mardin
- Department of Ophthalmology, University of Erlangen (C.Y.M.), Erlangen, Germany
| | - Harry A Quigley
- Wilmer Eye Institute, Johns Hopkins University (H.A.Q.), Baltimore, Maryland, USA
| | | | - Brad Fortune
- Devers Eye Institute, Discoveries in Sight Research Laboratories, Legacy Research Institute (S.K.G., S.D., B.F.), Portland, Oregon, USA
| | - Anuwat Jiravarnsirikul
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory, Legacy Research Institute (S.H., H.Y., H.L., A.J., C.F.B.), Portland, Oregon, USA; Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University (A.J.), Bangkok, Thailand
| | - Camila Zangalli
- Department of Glaucoma, Hospital de Olhos Niteroi (C.Z.), Rio de Janeiro, Brazil
| | - Balwantray C Chauhan
- Ophthalmology and Visual Sciences, Dalhousie University (G.P.S., B.C.C.), Halifax, Nova Scotia, Canada
| | - Claude F Burgoyne
- From the Devers Eye Institute, Optic Nerve Head Research Laboratory, Legacy Research Institute (S.H., H.Y., H.L., A.J., C.F.B.), Portland, Oregon, USA.
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Braeu FA, Chuangsuwanich T, Tun TA, Perera S, Husain R, Thiery AH, Aung T, Barbastathis G, Girard MJA. AI-based clinical assessment of optic nerve head robustness superseding biomechanical testing. Br J Ophthalmol 2024; 108:223-231. [PMID: 36627175 DOI: 10.1136/bjo-2022-322374] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 12/22/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND/AIMS To use artificial intelligence (AI) to: (1) exploit biomechanical knowledge of the optic nerve head (ONH) from a relatively large population; (2) assess ONH robustness (ie, sensitivity of the ONH to changes in intraocular pressure (IOP)) from a single optical coherence tomography (OCT) volume scan of the ONH without the need for biomechanical testing and (3) identify what critical three-dimensional (3D) structural features dictate ONH robustness. METHODS 316 subjects had their ONHs imaged with OCT before and after acute IOP elevation through ophthalmo-dynamometry. IOP-induced lamina cribrosa (LC) deformations were then mapped in 3D and used to classify ONHs. Those with an average effective LC strain superior to 4% were considered fragile, while those with a strain inferior to 4% robust. Learning from these data, we compared three AI algorithms to predict ONH robustness strictly from a baseline (undeformed) OCT volume: (1) a random forest classifier; (2) an autoencoder and (3) a dynamic graph convolutional neural network (DGCNN). The latter algorithm also allowed us to identify what critical 3D structural features make a given ONH robust. RESULTS All three methods were able to predict ONH robustness from a single OCT volume scan alone and without the need to perform biomechanical testing. The DGCNN (area under the curve (AUC): 0.76±0.08) outperformed the autoencoder (AUC: 0.72±0.09) and the random forest classifier (AUC: 0.69±0.05). Interestingly, to assess ONH robustness, the DGCNN mainly used information from the scleral canal and the LC insertion sites. CONCLUSIONS We propose an AI-driven approach that can assess the robustness of a given ONH solely from a single OCT volume scan of the ONH, and without the need to perform biomechanical testing. Longitudinal studies should establish whether ONH robustness could help us identify fast visual field loss progressors. PRECIS Using geometric deep learning, we can assess optic nerve head robustness (ie, sensitivity to a change in IOP) from a standard OCT scan that might help to identify fast visual field loss progressors.
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Affiliation(s)
- Fabian A Braeu
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Singapore-MIT Alliance for Research and Technology, Singapore
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore
| | - Thanadet Chuangsuwanich
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore
| | - Tin A Tun
- Singapore Eye Research Institute, Singapore
- Singapore National Eye Centre, Singapore
| | - Shamira Perera
- Singapore Eye Research Institute, Singapore
- Singapore National Eye Centre, Singapore
| | - Rahat Husain
- Singapore Eye Research Institute, Singapore
- Singapore National Eye Centre, Singapore
| | - Alexandre H Thiery
- Statistics and Applied Probability, National University of Singapore, Singapore
| | - Tin Aung
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Singapore Eye Research Institute, Singapore
- Singapore National Eye Centre, Singapore
- Duke-NUS Graduate Medical School, Singapore
| | - George Barbastathis
- Singapore-MIT Alliance for Research and Technology, Singapore
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Michaël J A Girard
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore
- Duke-NUS Graduate Medical School, Singapore
- Institute for Molecular and Clinical Ophthalmology, Basel, Switzerland
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Singappuli R, Rahman W, Abeysiri P. Significant improvement in structural and functional glaucoma damage in an adult patient following large, rapid medical reduction of pressure. Eye (Lond) 2024:10.1038/s41433-023-02894-1. [PMID: 38172578 DOI: 10.1038/s41433-023-02894-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/16/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
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Kawai M, Goseki T, Hirasawa K, Ishikawa H, Shoji N. Changes in Optic Nerve Head Blood Flow During Horizontal Ocular Duction. Invest Ophthalmol Vis Sci 2024; 65:7. [PMID: 38170537 PMCID: PMC10768701 DOI: 10.1167/iovs.65.1.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 11/29/2023] [Indexed: 01/05/2024] Open
Abstract
Purpose In this study, we aimed to compare blood flow changes in the optic nerve head (ONH) during horizontal ocular duction among normal, primary open-angle glaucoma (POAG), and normal-tension glaucoma (NTG) eyes. Methods In this cross-sectional study, we included 90 eyes from 90 participants (30 control eyes, 30 POAG eyes, and 30 NTG eyes). ONH blood flow was measured with laser speckle flowgraphy using an external fixation light to induce central gaze, abduction, and adduction at 30 degrees for each eye. The mean blur rate (MBR) of the entire ONH area (MA), vascular region (MV), and tissue region (MT), and the change ratio were analyzed. The change ratio was defined as abduction or adduction value/central gaze value. Results In the control group, MA significantly decreased during adduction (22.9 ± 3.7) compared with that during central gaze (23.6 ± 3.9, P < 0.05). In the POAG group, MA (adduction = 17.4 ± 3.8 and abduction = 17.3 ± 3.6) and MV (adduction = 37.9 ± 5.6 and abduction = 38.0 ± 5.6) significantly decreased during adduction and abduction compared with those during central gaze (18.0 ± 4.1 and 39.5 ± 6.3, respectively, P < 0.05). In the NTG group, MA significantly decreased during adduction (17.4 ± 4.2) compared with that during central gaze (18.1 ± 4.6) and abduction (18.1 ± 4.8, P < 0.05). The change ratio did not differ between the glaucoma and control groups. Conclusions ONH blood flow decreased during horizontal ocular duction regardless of normal or glaucoma states; however, the change ratio was comparable between the normal and glaucoma groups.
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Affiliation(s)
- Manami Kawai
- Department of Ophthalmology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Toshiaki Goseki
- Department of Ophthalmology, Kitasato University School of Medicine, Kanagawa, Japan
- Department of Ophthalmology, International University of Health and Welfare Atami Hospital, Shizuoka, Japan
| | - Kazunori Hirasawa
- Department of Ophthalmology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Hitoshi Ishikawa
- Department of Orthoptics and Visual Science, Kitasato University School of Allied Health Sciences, Kanagawa, Japan
| | - Nobuyuki Shoji
- Department of Ophthalmology, Kitasato University School of Medicine, Kanagawa, Japan
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Otani T, Miyata K, Miki A, Wada S. Computational study on the effects of central retinal blood vessels with asymmetric geometries on optic nerve head biomechanics. Med Eng Phys 2024; 123:104086. [PMID: 38365339 DOI: 10.1016/j.medengphy.2023.104086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 11/28/2023] [Accepted: 12/10/2023] [Indexed: 02/18/2024]
Abstract
Optic nerve head (ONH) biomechanics are associated with glaucoma progression and have received considerable attention. Central retinal vessels (CRVs) oriented asymmetrically in the ONH are the single blood supply source to the retina and are believed to act as mechanically stable elements in the ONH in response to intraocular pressure (IOP). However, these mechanical effects are considered negligible in ONH biomechanical studies and received less attention. This study investigated the effects of CRVs on ONH biomechanics taking into consideration three-dimensional asymmetric CRV geometries. A CRV geometry was constructed based on CRV centerlines extracted from optical coherence tomography ONH images in eight healthy subjects and superimposed in the idealized ONH geometry established in previous studies. Mechanical analyses of the ONH in response to the IOP were conducted in the cases with and without CRVs for comparison. Obtained results demonstrated that the CRVs induced anisotropic ONH deformation, particularly in the lamina cribrosa and the associated upper neural tissues (prelamina) with wide ranges of spatial strain distributions. These results indicated that the CRVs result in anisotropic deformation with local strain concentration, rather than function to mechanically support in response to the IOP as in the conventional thinking in ophthalmology.
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Affiliation(s)
- Tomohiro Otani
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan.
| | - Kota Miyata
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan
| | - Atsuya Miki
- Department of Myopia Control Research, Aichi Medical University, Japan
| | - Shigeo Wada
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan
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Han S, Yang X, Yang Y, Zheng Y, Liu W, Du D. Numerical simulation of mechanical properties of epiretinal membrane peeling. Comput Methods Biomech Biomed Engin 2024; 27:204-210. [PMID: 36786656 DOI: 10.1080/10255842.2023.2179365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 02/06/2023] [Indexed: 02/15/2023]
Abstract
An epiretinal membrane (ERM) is a fibrocellular proliferation on the inner surface of the retina causing blurred and distorted central vision. Surgery is the only effective method for ERM removal. This paper investigated the mechanical properties of ERM peeling using the finite element (FE) method. A FE model of ERM formation on the retina surface was constructed. The failure criterion was applied to the attachment pegs to represent the adhesive force between the ERM and retina. The simulation results were consistent with the experimental data in published research. The maximum peeling force was 4.1 mN at a peeling velocity of 2 mm/s and an angle of 30°. The peeling force was minimum at the peeling angle of 45° and increased with the increase in peeling velocity and Young's modulus of the membrane. The outcome of this paper can improve the safety and efficiency of ERM removal.
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Affiliation(s)
- Shaofeng Han
- School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing, China
| | - Xiaohan Yang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Yang Yang
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
| | - Yu Zheng
- College of Automation and College of Artificial Intelligence, Nanjing University of Posts and Telecommunications, Nanjing, China
| | - Wu Liu
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Dongmei Du
- School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing, China
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Korneva A, Kimball EC, Johnson TV, Quillen SE, Pease ME, Quigley HA, Nguyen TD. Comparison of the Biomechanics of the Mouse Astrocytic Lamina Cribrosa Between Glaucoma and Optic Nerve Crush Models. Invest Ophthalmol Vis Sci 2023; 64:14. [PMID: 38088825 PMCID: PMC10720758 DOI: 10.1167/iovs.64.15.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 11/14/2023] [Indexed: 12/17/2023] Open
Abstract
Purpose The strain response of the mouse astrocytic lamina (AL) to an ex vivo mechanical test was compared between two protocols: eyes that underwent sustained intraocular pressure (IOP) increase and eyes after optic nerve crush. Methods Chronic IOP elevation was induced by microbead injection or the optic nerve was crushed in mice with widespread green fluorescence. After 3 days or 6 weeks, eyes were inflation tested by a published method of two-photon fluorescence to image the AL. Digital volume correlation was used to calculate strains. Optic nerve axon damage was also evaluated. Results In the central AL but not the peripheral AL, four strains were greater in eyes at the 3-day glaucoma time point than control (P from 0.029 to 0.049, n = 8 eyes per group). Also, at this time point, five strains were greater in the central AL compared to the peripheral AL (P from 0.041 to 0.00003). At the 6-week glaucoma time point, the strains averaged across the specimen, in the central AL, and the peripheral AL were indistinguishable from the respective controls. Strains were not significantly different between controls and eyes 3 days or 6 weeks after crush (n = 8 and 16). Conclusions We found alterations in the ex vivo mechanical behavior in eyes from mice with experimental glaucoma but not in those with crushed optic nerves. The results of this study demonstrate that significant axon injury does not directly affect mechanical behavior of the astrocytic lamina.
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Affiliation(s)
- Arina Korneva
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Elizabeth C. Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Thomas V. Johnson
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Sarah E. Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Mary E. Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Harry A. Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Thao D. Nguyen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland, United States
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11
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Girkin CA, Garner MA, Gardiner SK, Clark ME, Hubbard M, Karuppanan U, Bianco G, Bruno L, Fazio MA. Displacement of the Lamina Cribrosa With Acute Intraocular Pressure Increase in Brain-Dead Organ Donors. Invest Ophthalmol Vis Sci 2023; 64:19. [PMID: 38099735 PMCID: PMC10729839 DOI: 10.1167/iovs.64.15.19] [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: 05/30/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Purpose To examine deformations of the optic nerve head (ONH) deep tissues in response to acute elevation of intraocular pressure (IOP). Methods Research-consented brain-dead organ donors underwent imaging by spectral domain optical coherence tomography (OCT). OCT imaging was repeated while the eye was sequentially maintained at manometric pressures of 10, 30, and 50 mm Hg. Radial scans of the ONH were automatically segmented by deep learning and quantified in three dimensions by a custom algorithm. Change in lamina cribrosa (LC) depth and choroidal thickness was correlated with IOP and age by linear mixed-effect models. LC depth was computed against commonly utilized reference planes. Results Twenty-six eyes from 20 brain-dead organ donors (age range, 22-62 years; median age, 43 years) were imaged and quantified. LC depth measured against a reference plane based on Bruch's membrane (BM), BM opening, and an anterior sclera canal opening plane showed both a reduction and an increase in LC depth with IOP elevation. LC depth universally increased in depth when measured against a sclera reference plane. Choroidal (-0.5222 µm/mm Hg, P < 0.001) and retinal nerve fiber layer thickness (-0.0717 µm/mm Hg, P < 0.001) significantly thinned with increasing IOP. The magnitude of LC depth change with IOP was significantly smaller with increasing age (P < 0.03 for all reference planes). Conclusions LC depth changes with IOP reduce with age and are significantly affected by the reference plane of choice, which highlights a need for standardizing LC metrics to properly follow progressive remodeling of the loadbearing tissues of the ONH by OCT imaging and for the definition of a reference database.
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Affiliation(s)
- Christopher A. Girkin
- Department of Ophthalmology, University of Alabama at Birmingham/Callahan Eye Hospital, Birmingham, Alabama, United States
| | - Mary A. Garner
- Department of Neuroscience, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, United States
| | | | - Mark E. Clark
- Department of Ophthalmology, University of Alabama at Birmingham/Callahan Eye Hospital, Birmingham, Alabama, United States
| | | | - Udayakumar Karuppanan
- Department of Ophthalmology, University of Alabama at Birmingham/Callahan Eye Hospital, Birmingham, Alabama, United States
| | - Gianfranco Bianco
- Department of Ophthalmology, University of Alabama at Birmingham/Callahan Eye Hospital, Birmingham, Alabama, United States
| | - Luigi Bruno
- Department of Mechanical, Energy and Management Engineering, University of Calabria, Rende, Italy
| | - Massimo A. Fazio
- Department of Ophthalmology, University of Alabama at Birmingham/Callahan Eye Hospital, Birmingham, Alabama, United States
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12
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Czerpak CA, Ling YTT, Jefferys JL, Quigley HA, Nguyen TD. The Curvature, Collagen Network Structure, and Their Relationship to the Pressure-Induced Strain Response of the Human Lamina Cribrosa in Normal and Glaucoma Eyes. J Biomech Eng 2023; 145:101005. [PMID: 37382629 PMCID: PMC10405282 DOI: 10.1115/1.4062846] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023]
Abstract
The lamina cribrosa (LC) is a connective tissue in the optic nerve head (ONH). The objective of this study was to measure the curvature and collagen microstructure of the human LC, compare the effects of glaucoma and glaucoma optic nerve damage, and investigate the relationship between the structure and pressure-induced strain response of the LC in glaucoma eyes. Previously, the posterior scleral cups of 10 normal eyes and 16 diagnosed glaucoma eyes were subjected to inflation testing with second harmonic generation (SHG) imaging of the LC and digital volume correlation (DVC) to calculate the strain field. In this study, we applied a custom microstructural analysis algorithm to the maximum intensity projection of SHG images to measure features of the LC beam and pore network. We also estimated the LC curvatures from the anterior surface of the DVC-correlated LC volume. Results showed that the LC in glaucoma eyes had larger curvatures p≤0.03), a smaller average pore area (p = 0.001), greater beam tortuosity (p < 0.0001), and more isotropic beam structure (p = 0.01) than in normal eyes. The difference measured between glaucoma and normal eyes may indicate remodeling of the LC with glaucoma or baseline differences that contribute to the development of glaucomatous axonal damage.
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Affiliation(s)
- Cameron A Czerpak
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218
| | - Yik Tung Tracy Ling
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218
| | - Joan L Jefferys
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, MD 21287
| | - Harry A Quigley
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, MD 21287
| | - Thao D Nguyen
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218; Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, MD 21287
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13
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Yuhas PT, McHugh-Morrison C, Canavan J, Jeyandran J, Mahmoud AM, Roberts CJ. Intereye Differences in the Clinical Assessment of Intraocular Pressure and Ocular Biomechanics. Optom Vis Sci 2023; 100:688-696. [PMID: 37639554 PMCID: PMC10662582 DOI: 10.1097/opx.0000000000002066] [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: 04/07/2023] [Accepted: 07/23/2023] [Indexed: 08/31/2023] Open
Abstract
SIGNIFICANCE Clinicians and researchers will have evidence whether intereye differences confound clinical measurements of intraocular pressure or of ocular biomechanical parameters. PURPOSE The purpose of this study was to determine whether intraocular pressure and biomechanical parameters, as measured by the Ocular Response Analyzer (ORA) and by Cornea Visualization with Scheimpflug Technology (CorVis ST), are different between the first and second eye measured. METHODS Intraocular pressure and biomechanical parameters were collected from both eyes of healthy participants (N = 139). The ORA measured corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, and corneal hysteresis. The CorVis ST measured biomechanically corrected intraocular pressure, stiffness parameter at first applanation, and stiffness parameter at highest concavity. For each measurement, a paired t test compared the value of the first eye measured against that of the second eye measured. RESULTS For the ORA, Goldmann-correlated intraocular pressure was significantly higher ( P = .001) in the first eye (14.8 [3.45] mmHg) than in the second eye (14.3 [3.63] mmHg). For the CorVis ST, biomechanically corrected intraocular pressure was significantly higher ( P < .001) in the second eye (14.7 [2.14] mmHg) than in the first eye (14.3 [2.11] mmHg). Stiffness parameter at first applanation (intereye difference, 6.85 [9.54] mmHg/mm) was significantly ( P < .001) higher in the first eye than in the second eye. Stiffness parameter at highest concavity was significantly higher ( P = .01) in the second eye (14.3 [3.18] mmHg/mm) than in the first eye (14.0 [3.13] mmHg/mm). CONCLUSIONS Although there were statistically significant intereye differences in intraocular pressure and in biomechanical parameters for both devices, the variations were small and thus unlikely to affect clinical outcomes.
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Affiliation(s)
| | | | - Joshua Canavan
- College of Optometry, The Ohio State University, Columbus, Ohio
| | | | - Ashraf M. Mahmoud
- Department of Ophthalmology and Visual Sciences, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Cynthia J. Roberts
- Department of Ophthalmology and Visual Sciences, College of Medicine, The Ohio State University, Columbus, Ohio
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio
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14
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Ling YTT, Korneva A, Quigley HA, Nguyen TD. Computational study of the mechanical behavior of the astrocyte network and axonal compartments in the mouse optic nerve head. Biomech Model Mechanobiol 2023; 22:1751-1772. [PMID: 37573553 PMCID: PMC10988382 DOI: 10.1007/s10237-023-01752-z] [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: 10/01/2022] [Accepted: 07/15/2023] [Indexed: 08/15/2023]
Abstract
Glaucoma is a blinding disease characterized by the degeneration of the retinal ganglion cell (RGC) axons at the optic nerve head (ONH). A major risk factor for glaucoma is the intraocular pressure (IOP). However, it is currently impossible to measure the IOP-induced mechanical response of the axons of the ONH. The objective of this study was to develop a computational modeling method to estimate the IOP-induced strains and stresses in the axonal compartments in the mouse astrocytic lamina (AL) of the ONH, and to investigate the effect of the structural features on the mechanical behavior. We developed experimentally informed finite element (FE) models of six mouse ALs to investigate the effect of structure on the strain responses of the astrocyte network and axonal compartments to pressure elevation. The specimen-specific geometries of the FE models were reconstructed from confocal fluorescent images of cryosections of the mouse AL acquired in a previous study that measured the structural features of the astrocytic processes and axonal compartments. The displacement fields obtained from digital volume correlation in prior inflation tests of the mouse AL were used to determine the displacement boundary conditions of the FE models. We then applied Gaussian process regression to analyze the effects of the structural features on the strain outcomes simulated for the axonal compartments. The axonal compartments experienced, on average, 6 times higher maximum principal strain but 1800 times lower maximum principal stress compared to those experienced by the astrocyte processes. The strains experienced by the axonal compartments were most sensitive to variations in the area of the axonal compartments. Larger axonal compartments that were more vertically aligned, closer to the AL center, and with lower local actin area fraction had higher strains. Understanding the factors affecting the deformation in the axonal compartments will provide insights into mechanisms of glaucomatous axonal damage.
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Affiliation(s)
- Yik Tung Tracy Ling
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Arina Korneva
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Harry A Quigley
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Thao D Nguyen
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- Department of Materials Science, Johns Hopkins University, Baltimore, MD, USA.
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15
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Sayah DN, Mazzaferri J, Descovich D, Costantino S, Lesk MR. Ocular rigidity and neuroretinal damage in patients with vasospasticity: a pilot study. CANADIAN JOURNAL OF OPHTHALMOLOGY 2023; 58:338-345. [PMID: 35358484 DOI: 10.1016/j.jcjo.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Evidence suggests that ocular blood flow dysregulation in patients with vasospasticity could occur in response to biomechanical stimuli, contributing to optic nerve head susceptibility in glaucoma. We evaluate the role of vasospasticity in the association between ocular rigidity (OR) and neuroretinal damage, hypothesizing that low OR correlates with greater glaucoma damage in patients with vasospasticity. DESIGN Cross-sectional study. PARTICIPANTS Patients with open-angle glaucoma (OAG), suspect discs, or no glaucoma. METHODS OR was measured using a noninvasive, validated method developed by our group. Retinal nerve fibre layer (RNFL) and ganglion cell complex thicknesses were acquired using spectral domain optical coherence tomography. Vasospasticity was assessed by a standardized questionnaire that was based on existing validated questionnaires and adapted to our requirements. Atherosclerosis was evaluated based on Broadway and Drance's (1998) cardiovascular disease score. Correlations between OR and structural parameters were assessed in patients with vasospasticity and those with atherosclerosis. RESULTS Of 118 patients with either OAG (n = 67), suspect discs (n = 26), or no glaucoma (n = 25) who were recruited consecutively, 10 were classified as having vasospasticity, and 37 as having atherosclerosis. In the vasospastic group, significant correlations were found between OR and the minimum ganglion cell complex thickness (rs = 0.681, p = 0.030), the average RNFL thickness (rs = 0.745, p = 0.013), and the RNFL in the temporal quadrant (rs = 0.772, p = 0.009), indicating more damage with lower OR. Similar trends were maintained when applying multiple testing correction; however, only the eighth RNFL clock hour corresponding to the inferior-temporal peripapillary region remained significantly correlated with OR in the vasospastic group (p = 0.015). In contrast, no correlation was found in the atherosclerotic group (p > 0.05). CONCLUSIONS The findings of the current pilot study indicate a trend for more neuronal structural damage in less-rigid eyes of patients with vasospasticity, meaning that OR may play a greater role in glaucoma in vasospastic patients than in patients with atherosclerosis. Although these results provide interesting insight into the pathophysiology of OAG, further investigation is needed to confirm our observations.
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Affiliation(s)
- Diane N Sayah
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC; Department of Ophthalmology, Université de Montréal, Montreal, QC
| | | | | | - Santiago Costantino
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC; Department of Ophthalmology, Université de Montréal, Montreal, QC; Centre Universitaire d'Ophtalmologie (CUO), Maisonneuve-Rosemont Hospital, CIUSSS-E, Montreal, QC
| | - Mark R Lesk
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC; Department of Ophthalmology, Université de Montréal, Montreal, QC; Centre Universitaire d'Ophtalmologie (CUO), Maisonneuve-Rosemont Hospital, CIUSSS-E, Montreal, QC.
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16
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Incekalan TK, Peköz BÇ. Usability of Real-Time Elastography for the Diagnosis of Primary Open Angle and Pseudoexfoliation Glaucoma. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2023; 42:1471-1480. [PMID: 36534582 DOI: 10.1002/jum.16157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
OBJECTIVES This study aims to investigate real-time elastography (RTE) use in the evaluation of the optic nerve head (ONH) and peripapillary structures for the diagnosis of primary open angle (POAG) and pseudoexfoliation (PEX) glaucoma. METHODS This case-controlled study included 30 patients with POAG, 30 patients with PEX glaucoma, and 30 age-matched control subjects. All of the participants underwent comprehensive ophthalmological examinations covering vessel density of optic nerve and retinal nerve fiber layer (RNFL) thickness measurements with optical cohorence tomography angiography and mean deviation (MD) measurements with Humphrey II Perimetry Visual Field Analyzer. In vivo evaluation of the biomechanical properties of the ONH and peripapillary structures were performed with RTE in all participants. RESULTS We observed higher ratios of orbital fat to optic nerve head (ROFON) values (P = .008) and strain ratios of orbital fat to scleral-choroidal-retinal complex (ROFSCR) values (P = .004) in the POAG group compared with PEX glaucoma group and higher ROFON (P = .012) and ROFSCR values (P = .004) in PEX glaucoma group than the control group. ROFON and ROFSCR values were positively correlated with glaucoma duration and negatively correlated with MD, radial peripapillary vessel density (RPCVD), and inside disc vessel density in both glaucoma groups (P < .005; only in the PEX glaucoma group for MD and ROFSCR, P = .445). CONCLUSION Determining the biomechanical properties of ONH and peripapillary structures with RTE in glaucomatous eyes may offer a new perspective on the diagnosis and follow-up of the progression of the disease.
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Affiliation(s)
- Tuğba Kurumoğlu Incekalan
- Department of Opthalmology, University of Health Sciences Adana City Training and Research Hospital, Adana, Turkey
| | - Burçak Çakır Peköz
- Department of Radiology, University of Health Sciences Adana City Training and Research Hospital, Adana, Turkey
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17
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Korneva A, Kimball EC, Quillen S, Jefferys JL, Nawathe M, Ling YTT, Nguyen TD, Quigley HA. Mechanical strain in the mouse astrocytic lamina increases after exposure to recombinant trypsin. Acta Biomater 2023; 163:312-325. [PMID: 35196555 PMCID: PMC9391529 DOI: 10.1016/j.actbio.2022.02.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/21/2022] [Accepted: 02/16/2022] [Indexed: 11/30/2022]
Abstract
The responses of astrocytes in the optic nerve head (ONH) to mechanical and biochemical stimuli are important to understanding the degeneration of retinal ganglion cell axons in glaucoma. The ONH in glaucoma is vulnerable to stress produced by the intraocular pressure (IOP). Notably, after three days of elevated IOP in a mouse model, the junctions between the astrocytic processes and the peripapillary sclera were altered and the structural compliance of the ONH increased. In order to simulate this aspect of glaucomatous remodeling, explanted mouse eyes were treated with TrypLE, a recombinant trypsin enzyme. Treatment with TrypLE caused the periphery of the astrocytic lamina to contract radially by 0.044 ± 0.038. Transmission electron microscopy showed that TrypLE caused a separation of the end-feet of the astrocyte processes from the basement membrane at the junction with the sclera. Inflation testing after treatment with TrypLE caused an increased strain response in the astrocytic lamina compared to the strain response before treatment. The greatest increase was in the radial Green-Lagrange strain, Err = 0.028 ± 0.009, which increased by 340%. The alterations in the microstructure and in the strain response of the astrocytic lamina reported in mouse experimental glaucoma were partially reproduced by experimental treatment of mouse eyes with TrypLE. The results herein suggest that separation of junctions between the astrocyte processes and the sclera may be instrumental in increasing the structural compliance of the ONH after a period of elevated IOP. STATEMENT OF SIGNIFICANCE: Astrocytes of the optic nerve of the eye spread out from edge to edge across the optic nerve in a region referred to as the astrocytic lamina. In an experimental model of glaucoma caused by elevated eye-pressure, there is disruption of the connections between astrocytes and the edge of the astrocytic lamina. We caused a similar event in the lamina by incubating explanted mouse eyes with an enzyme. Disruption of the astrocyte connections to the edge of their tissue caused the tissue to stretch more when we increased the eye-pressure, compared to the control tissue. This work is the first on the tissue of the optic nerve to demonstrate the importance of cell connections in preventing the over-stretching of the astrocytic lamina.
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Affiliation(s)
- Arina Korneva
- Glaucoma Center of Excellence, Johns Hopkins Wilmer Eye Institute, United States; Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD 21218, United States.
| | - Elizabeth C Kimball
- Glaucoma Center of Excellence, Johns Hopkins Wilmer Eye Institute, United States.
| | - Sarah Quillen
- Glaucoma Center of Excellence, Johns Hopkins Wilmer Eye Institute, United States.
| | - Joan L Jefferys
- Glaucoma Center of Excellence, Johns Hopkins Wilmer Eye Institute, United States.
| | - Manasi Nawathe
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, United States.
| | - Yik Tung Tracy Ling
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States.
| | - Thao D Nguyen
- Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD 21218, United States; Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Department of Materials Science, Johns Hopkins University, Baltimore, MD 21218, United States.
| | - Harry A Quigley
- Glaucoma Center of Excellence, Johns Hopkins Wilmer Eye Institute, United States; Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD 21218, United States.
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18
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Gardiner SK, Cull G, Fortune B. Retinal Vessel Pulsatile Characteristics Associated With Vascular Stiffness Can Predict the Rate of Functional Progression in Glaucoma Suspects. Invest Ophthalmol Vis Sci 2023; 64:30. [PMID: 37335567 PMCID: PMC10284309 DOI: 10.1167/iovs.64.7.30] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/26/2023] [Indexed: 06/21/2023] Open
Abstract
Purpose Tissue stiffening and alterations in retinal blood flow have both been suggested as causative mechanisms of glaucomatous damage. We tested the hypothesis that retinal blood vessels also stiffen, using laser speckle flowgraphy (LSFG) to characterize vascular resistance. Methods In the longitudinal Portland Progression Project, 231 eyes of 124 subjects received LSFG scans of the optic nerve head (ONH) and automated perimetry every 6 months for six visits. Eyes were classified as either "glaucoma suspect" or "glaucoma" eyes based on the presence of functional loss on the first visit. Vascular resistance was quantified using the mean values of several instrument-defined parameterizations of the pulsatile waveform measured by LSFG, either in major vessels within the ONH (serving the retina) or in capillaries within ONH tissue, and age-adjusted using a separate group of 127 healthy eyes of 63 individuals. Parameters were compared against the severity and rate of change of functional loss using mean deviation (MD) over the six visits, within the two groups. Results Among 118 "glaucoma suspect" eyes (average MD, -0.4 dB; rate, -0.45 dB/y), higher vascular resistance was related to faster functional loss, but not current severity of loss. Parameters measured in major vessels were stronger predictors of rate than parameters measured in tissue. Among 113 "glaucoma" eyes (average MD, -4.3 dB; rate, -0.53 dB/y), higher vascular resistance was related to more severe current loss but not rate of loss. Conclusions Higher retinal vascular resistance and, by likely implication, stiffer retinal vessels were associated with more rapid functional loss in eyes without significant existing loss at baseline.
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Affiliation(s)
| | - Grant Cull
- Devers Eye Institute, Legacy Health, Portland, Oregon, United States
| | - Brad Fortune
- Devers Eye Institute, Legacy Health, Portland, Oregon, United States
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19
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Jeong Y, Davis CHO, Muscarella AM, Deshpande V, Kim KY, Ellisman MH, Marsh-Armstrong N. Glaucoma-associated Optineurin mutations increase transmitophagy in a vertebrate optic nerve. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542507. [PMID: 37398269 PMCID: PMC10312487 DOI: 10.1101/2023.05.26.542507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
We previously described a process referred to as transmitophagy where mitochondria shed by retinal ganglion cell (RGC) axons are transferred to and degraded by surrounding astrocytes in the optic nerve head of mice. Since the mitophagy receptor Optineurin (OPTN) is one of few large-effect glaucoma genes and axonal damage occurs at the optic nerve head in glaucoma, here we explored whether OPTN mutations perturb transmitophagy. Live-imaging of Xenopus laevis optic nerves revealed that diverse human mutant but not wildtype OPTN increase stationary mitochondria and mitophagy machinery and their colocalization within, and in the case of the glaucoma-associated OPTN mutations also outside of, RGC axons. These extra-axonal mitochondria are degraded by astrocytes. Our studies support the view that in RGC axons under baseline conditions there are low levels of mitophagy, but that glaucoma-associated perturbations in OPTN result in increased axonal mitophagy involving the shedding and astrocytic degradation of the mitochondria.
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Affiliation(s)
- Yaeram Jeong
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | | | - Aaron M. Muscarella
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Viraj Deshpande
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Mark H. Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego School of Medicine, La Jolla, CA 92093, USA
| | - Nicholas Marsh-Armstrong
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Lead contact
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20
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Zu H, Zhang K, Zhang H, Qian X. An Inverse Method to Determine Mechanical Parameters of Porcine Vitreous Bodies Based on the Indentation Test. Bioengineering (Basel) 2023; 10:646. [PMID: 37370577 DOI: 10.3390/bioengineering10060646] [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: 04/20/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
The vitreous body keeps the lens and retina in place and protects these tissues from physical insults. Existing studies have reported that the mechanical properties of vitreous body varied after liquefaction, suggesting mechanical properties could be effective parameters to identify vitreous liquefaction process. Thus, in this work, we aimed to propose a method to determine the mechanical properties of vitreous bodies. Fresh porcine eyes were divided into three groups, including the untreated group, the 24 h liquefaction group and the 48 h liquefaction group, which was injected collagenase and then kept for 24 h or 48 h. The indentation tests were carried out on the vitreous body in its natural location while the posterior segment of the eye was fixed in the container. A finite element model of a specimen undertaking indentation was constructed to simulate the indentation test with surface tension of vitreous body considered. Using the inverse method, the mechanical parameters of the vitreous body and the surface tension coefficient were determined. For the same parameter, values were highest in the untreated group, followed by the 24 h liquefaction group and the lowest in the 48 h liquefaction group. For C10 in the neo-Hookean model, the significant differences were found between the untreated group and liquefaction groups. This work quantified vitreous body mechanical properties successfully using inverse method, which provides a new method for identifying vitreous liquefactions related studies.
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Affiliation(s)
- Haicheng Zu
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
| | - Kunya Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
| | - Haixia Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
| | - Xiuqing Qian
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
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21
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Patel NB, Carter-Dawson L, Frishman LJ. Neuroretinal Rim Response to Transient Intraocular Pressure Challenge Predicts the Extent of Retinal Ganglion Cell Loss in Experimental Glaucoma. Invest Ophthalmol Vis Sci 2023; 64:30. [PMID: 37256608 PMCID: PMC10233313 DOI: 10.1167/iovs.64.5.30] [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: 12/13/2022] [Accepted: 05/12/2023] [Indexed: 06/01/2023] Open
Abstract
Purpose To determine if the optic nerve head (ONH) response to transient elevated intraocular pressure (IOP) can predict the extent of neural loss in the nonhuman primate experimental glaucoma model. Methods The anterior chamber pressure of 21 healthy animals (5.4 ± 1.2 years, 8 female) was adjusted to 25 mm Hg for two hours followed by 10 mm Hg for an additional two hours. For the duration of IOP challenge the ONH was imaged using radial optical coherence tomography (OCT) scans at five-minute intervals. Afterward, a randomized sample of 14 of these subjects had unilateral experimental glaucoma induced and were monitored with OCT imaging, tonometry, and ocular biometry at two-week intervals. Results With pressure challenge, the maximum decrease in ONH minimum rim width (MRW) was 40 ± 10.5 µm at 25 mm Hg and was correlated with the precannulation MRW, Bruch's membrane opening (BMO) position, and the anterior lamina cribrosa surface position (P = 0.01). The maximum return of MRW at 10 mm Hg was 16.1 ± 5.0 µm and was not associated with any precannulation ONH feature (P = 0.24). However, healthy eyes with greater thickness return at 10 mm Hg had greater loss of MRW and retinal nerve fiber layer (RNFL) at a cumulative IOP of 1000 mm Hg · days after induction of experimental glaucoma. In addition, MRW and RNFL thinning was correlated with an increase in axial length (P < 0.01). Conclusion This study's findings suggest that the ONH's response to transient changes in IOP are associated with features of the ONH and surrounding tissues. The neural rim properties at baseline and the extent of axial elongation are associated with the severity of glaucomatous loss in the nonhuman primate model.
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Affiliation(s)
- Nimesh B Patel
- University of Houston College of Optometry, Houston, Texas, United States
| | | | - Laura J Frishman
- University of Houston College of Optometry, Houston, Texas, United States
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Foong TY, Hua Y, Amini R, Sigal IA. Who bears the load? IOP-induced collagen fiber recruitment over the corneoscleral shell. Exp Eye Res 2023; 230:109446. [PMID: 36935071 PMCID: PMC10133210 DOI: 10.1016/j.exer.2023.109446] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/25/2023] [Accepted: 03/16/2023] [Indexed: 03/19/2023]
Abstract
Collagen is the main load-bearing component of cornea and sclera. When stretched, both of these tissues exhibit a behavior known as collagen fiber recruitment. In recruitment, as the tissues stretch the constitutive collagen fibers lose their natural waviness, progressively straightening. Recruited, straight, fibers bear substantially more mechanical load than non-recruited, wavy, fibers. As such, the process of recruitment underlies the well-established nonlinear macroscopic behavior of the corneoscleral shell. Recruitment has an interesting implication: when recruitment is incomplete, only a fraction of the collagen fibers is actually contributing to bear the loads, with the rest remaining "in reserve". In other words, at a given intraocular pressure (IOP), it is possible that not all the collagen fibers of the cornea and sclera are actually contributing to bear the loads. To the best of our knowledge, the fraction of corneoscleral shell fibers recruited and contributing to bear the load of IOP has not been reported. Our goal was to obtain regionally-resolved estimates of the fraction of corneoscleral collagen fibers recruited and in reserve. We developed a fiber-based microstructural constitutive model that could account for collagen fiber undulations or crimp via their tortuosity. We used experimentally-measured collagen fiber crimp tortuosity distributions in human eyes to derive region-specific nonlinear hyperelastic mechanical properties. We then built a three-dimensional axisymmetric model of the globe, assigning region-specific mechanical properties and regional anisotropy. The model was used to simulate the IOP-induced shell deformation. The model-predicted tissue stretch was then used to quantify collagen recruitment within each shell region. The calculations showed that, at low IOPs, collagen fibers in the posterior equator were recruited the fastest, such that at a physiologic IOP of 15 mmHg, over 90% of fibers were recruited, compared with only a third in the cornea and the peripapillary sclera. The differences in recruitment between regions, in turn, mean that at a physiologic IOP the posterior equator had a fiber reserve of only 10%, whereas the cornea and peripapillary sclera had two thirds. At an elevated IOP of 50 mmHg, collagen fibers in the limbus and the anterior/posterior equator were almost fully recruited, compared with 90% in the cornea and the posterior sclera, and 70% in the peripapillary sclera and the equator. That even at such an elevated IOP not all the fibers were recruited suggests that there are likely other conditions that challenge the corneoscleral tissues even more than IOP. The fraction of fibers recruited may have other potential implications. For example, fibers that are not bearing loads may be more susceptible to enzymatic digestion or remodeling. Similarly, it may be possible to control tissue stiffness through the fraction of recruited fibers without the need to add or remove collagen.
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Affiliation(s)
- Tian Yong Foong
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Yi Hua
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Biomedical Engineering, University of Mississippi, MS, United States; Department of Mechanical Engineering, University of Mississippi, MS, United States
| | - Rouzbeh Amini
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, United States; Department of Bioengineering, Northeastern University, Boston, MA, United States
| | - Ian A Sigal
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh Medical Center and University of Pittsburgh, Pittsburgh, PA, United States.
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Brazuna R, Alonso RS, Salomão MQ, Fernandes BF, Ambrósio R. Ocular Biomechanics and Glaucoma. Vision (Basel) 2023; 7:vision7020036. [PMID: 37218954 DOI: 10.3390/vision7020036] [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: 03/14/2023] [Revised: 04/11/2023] [Accepted: 04/21/2023] [Indexed: 05/24/2023] Open
Abstract
Biomechanics is a branch of biophysics that deals with mechanics applied to biology. Corneal biomechanics have an important role in managing patients with glaucoma. While evidence suggests that patients with thin and stiffer corneas have a higher risk of developing glaucoma, it also influences the accurate measurement of intraocular pressure. We reviewed the pertinent literature to help increase our understanding of the biomechanics of the cornea and other ocular structures and how they can help optimize clinical and surgical treatments, taking into consideration individual variabilities, improve the diagnosis of suspected patients, and help monitor the response to treatment.
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Affiliation(s)
- Rodrigo Brazuna
- Department of Ophthalmology, Federal University of the State of Rio de Janeiro, Rio de Janeiro 22290-240, RJ, Brazil
| | - Ruiz S Alonso
- Department of Ophthalmology, Antonio Pedro University Hospital, Fluminense Federal University, Niterói 24033-900, RJ, Brazil
| | - Marcella Q Salomão
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04023-062, SP, Brazil
| | | | - Renato Ambrósio
- Department of Ophthalmology, Federal University of the State of Rio de Janeiro, Rio de Janeiro 22290-240, RJ, Brazil
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Lan G, Twa MD, Song C, Feng J, Huang Y, Xu J, Qin J, An L, Wei X. In vivo corneal elastography: A topical review of challenges and opportunities. Comput Struct Biotechnol J 2023; 21:2664-2687. [PMID: 37181662 PMCID: PMC10173410 DOI: 10.1016/j.csbj.2023.04.009] [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: 02/14/2023] [Revised: 04/07/2023] [Accepted: 04/12/2023] [Indexed: 05/16/2023] Open
Abstract
Clinical measurement of corneal biomechanics can aid in the early diagnosis, progression tracking, and treatment evaluation of ocular diseases. Over the past two decades, interdisciplinary collaborations between investigators in optical engineering, analytical biomechanical modeling, and clinical research has expanded our knowledge of corneal biomechanics. These advances have led to innovations in testing methods (ex vivo, and recently, in vivo) across multiple spatial and strain scales. However, in vivo measurement of corneal biomechanics remains a long-standing challenge and is currently an active area of research. Here, we review the existing and emerging approaches for in vivo corneal biomechanics evaluation, which include corneal applanation methods, such as ocular response analyzer (ORA) and corneal visualization Scheimpflug technology (Corvis ST), Brillouin microscopy, and elastography methods, and the emerging field of optical coherence elastography (OCE). We describe the fundamental concepts, analytical methods, and current clinical status for each of these methods. Finally, we discuss open questions for the current state of in vivo biomechanics assessment techniques and requirements for wider use that will further broaden our understanding of corneal biomechanics for the detection and management of ocular diseases, and improve the safety and efficacy of future clinical practice.
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Affiliation(s)
- Gongpu Lan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Michael D Twa
- College of Optometry, University of Houston, Houston, TX 77204, United States
| | - Chengjin Song
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
| | - JinPing Feng
- Institute of Engineering and Technology, Hubei University of Science and Technology, Xianning, Hubei 437100, China
| | - Yanping Huang
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jingjiang Xu
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jia Qin
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Lin An
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Xunbin Wei
- Biomedical Engineering Department, Peking University, Beijing 100081, China
- International Cancer Institute, Peking University, Beijing 100191, China
- Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, China
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25
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Safa BN, Bleeker A, Berdahl JP, Ethier CR. The Effects of Negative Periocular Pressure on Biomechanics of the Optic Nerve Head and Cornea: A Computational Modeling Study. Transl Vis Sci Technol 2023; 12:5. [PMID: 36745441 PMCID: PMC9910383 DOI: 10.1167/tvst.12.2.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose The purpose of this study was to evaluate the effects of negative periocular pressure (NPP), and concomitant intraocular pressure (IOP) lowering, on the biomechanics of the optic nerve head (ONH) and cornea. Methods We developed a validated finite element (FE) model of the eye to compute tissue biomechanical strains induced in response to NPP delivered using the Multi-Pressure Dial (MPD) system. The model was informed by clinical measurements of IOP lowering and was based on published tissue properties. We also conducted sensitivity analyses by changing pressure loads and tissue properties. Results Application of -7.9 mmHg NPP decreased strain magnitudes in the ONH by c. 50% whereas increasing corneal strain magnitudes by c. 25%. Comparatively, a similar increase in corneal strain was predicted to occur due to an increase in IOP of 4 mmHg. Sensitivity studies indicated that NPP lowers strain in the ONH by reducing IOP and that these effects persisted over a range of tissue stiffnesses and spatial distributions of NPP. Conclusions NPP is predicted to considerably decrease ONH strain magnitudes. It also increases corneal strain but to an extent expected to be clinically insignificant. Thus, using NPP to lower IOP and hence decrease ONH mechanical strain is likely biomechanically beneficial for patients with glaucoma. Translational Relevance This study provides the first description of how NPP affects ONH biomechanics and explains the underlying mechanism of ONH strain reduction. It complements current empirical knowledge about the MPD system and guides future studies of NPP as a treatment for glaucoma.
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Affiliation(s)
- Babak N. Safa
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA
| | - Adam Bleeker
- Dean McGee Eye Institute Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - John P. Berdahl
- Equinox Ophthalmic, Newport Beach, CA, USA,Vance Thompson Vision, Sioux Falls, SD, USA
| | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA
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26
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Sayah DN, Lesk MR. Ocular Rigidity and Current Therapy. Curr Eye Res 2023; 48:105-113. [PMID: 35763027 DOI: 10.1080/02713683.2022.2093380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Purpose: Ocular rigidity (OR) is an important biomechanical parameter of the eye accounting for the material and geometrical properties of the corneoscleral shell.Methods: This study used a literature search to review the role of ocular rigidity and the application of potential therapies targeting this parameter in glaucoma and myopia.Conclusion: Biomechanical modeling and improved understanding of the biochemistry, and molecular arrangement of sclera and its constituents have yielded important insights. Recent developments, including that of a non-invasive and direct OR measurement method and improved ocular imaging techniques are helping to elucidate the role of OR in healthy and diseased eyes by facilitating large scale and longitudinal clinical studies. Improved understanding of OR at the initial stages of disease processes and its alterations with disease progression will undoubtedly propel research in the field. Furthermore, a better understanding of the determinants of OR is helping to refine novel therapeutic approaches which target and alter the biomechanical properties of the sclera in sight-threatening conditions such as glaucoma and myopia.
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Affiliation(s)
- Diane N Sayah
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Canada.,School of Optometry, Université de Montréal, Montreal, Canada
| | - Mark R Lesk
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Canada.,Centre Universitaire d'ophtalmologie de l'Université de Montréal de l'Hôpital Maisonneuve-Rosemont, CIUSSS-E, Montreal, Canada
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Yuhas PT, Roberts CJ. Clinical Ocular Biomechanics: Where Are We after 20 Years of Progress? Curr Eye Res 2023; 48:89-104. [PMID: 36239188 DOI: 10.1080/02713683.2022.2125530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Purpose: Ocular biomechanics is an assessment of the response of the structures of the eye to forces that may lead to disease development and progression, or influence the response to surgical intervention. The goals of this review are (1) to introduce basic biomechanical principles and terminology, (2) to provide perspective on the progress made in the clinical study and assessment of ocular biomechanics, and (3) to highlight critical studies conducted in keratoconus, laser refractive surgery, and glaucoma in order to aid interpretation of biomechanical parameters in the laboratory and in the clinic.Methods: A literature review was first conducted of basic biomechanical studies related to ocular tissue. The subsequent review of ocular biomechanical studies was limited to those focusing on keratoconus, laser refractive surgery, or glaucoma using the only two commercially available devices that allow rapid assessment of biomechanical response in the clinic.Results: Foundational studies on ocular biomechanics used a combination of computer modeling and destructive forces on ex-vivo tissues. The knowledge gained from these studies could not be directly translated to clinical research and practice until the introduction of non-contact tonometers that quantified the deformation response of the cornea to an air puff, which represents a non-destructive, clinically appropriate load. The corneal response includes a contribution from the sclera which may limit corneal deformation. Two commercial devices are available, the Ocular Response Analyzer which produces viscoelastic parameters with a customized load for each eye, and the Corvis ST which produces elastic parameters with a consistent load for every eye. Neither device produces the classic biomechanical properties reported in basic studies, but rather biomechanical deformation response parameters which require careful interpretation.Conclusions: Research using clinical tools has enriched our understanding of how ocular disease alters ocular biomechanics, as well as how ocular biomechanics may influence the pathophysiology of ocular disease and response to surgical intervention.
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Affiliation(s)
- Phillip T Yuhas
- College of Optometry, The Ohio State University, Columbus, OH, USA
| | - Cynthia J Roberts
- Department of Ophthalmology and Visual Sciences, College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
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Chuangsuwanich T, Tun TA, Braeu FA, Wang X, Chin ZY, Panda SK, Buist M, Strouthidis N, Perera S, Nongpiur M, Aung T, Girard MJA. Differing Associations between Optic Nerve Head Strains and Visual Field Loss in Patients with Normal- and High-Tension Glaucoma. Ophthalmology 2023; 130:99-110. [PMID: 35964710 DOI: 10.1016/j.ophtha.2022.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 07/13/2022] [Accepted: 08/04/2022] [Indexed: 01/06/2023] Open
Abstract
PURPOSE To study the associations between optic nerve head (ONH) strains under intraocular pressure (IOP) elevation with retinal sensitivity in patients with glaucoma. DESIGN Clinic-based cross-sectional study. PARTICIPANTS Two hundred twenty-nine patients with primary open-angle glaucoma (subdivided into 115 patients with high-tension glaucoma [HTG] and 114 patients with normal-tension glaucoma [NTG]). METHODS For 1 eye of each patient, we imaged the ONH using spectral-domain OCT under the following conditions: (1) primary gaze and (2) primary gaze with acute IOP elevation (to approximately 35 mmHg) achieved through ophthalmodynamometry. A 3-dimensional strain-mapping algorithm was applied to quantify IOP-induced ONH tissue strain (i.e., deformation) in each ONH. Strains in the prelaminar tissue (PLT), the retina, the choroid, the sclera, and the lamina cribrosa (LC) were associated (using linear regression) with measures of retinal sensitivity from the 24-2 Humphrey visual field test (Carl Zeiss Meditec). This was performed globally, then locally according to a previously published regionalization scheme. MAIN OUTCOME MEASURES Associations between ONH strains and values of retinal sensitivity from visual field testing. RESULTS For patients with HTG, we found (1) significant negative linear associations between ONH strains and retinal sensitivity (P < 0.001; on average, a 1% increase in ONH strains corresponded to a decrease in retinal sensitivity of 1.1 decibels [dB]), (2) that high-strain regions colocalized with anatomically mapped regions of high visual field loss, and (3) that the strongest negative associations were observed in the superior region and in the PLT. In contrast, for patients with NTG, no significant associations between strains and retinal sensitivity were observed except in the superotemporal region of the LC. CONCLUSIONS We found significant negative associations between IOP-induced ONH strains and retinal sensitivity in a relatively large glaucoma cohort. Specifically, patients with HTG who experienced higher ONH strains were more likely to exhibit lower retinal sensitivities. Interestingly, this trend in general was less pronounced in patients with NTG, which could suggest a distinct pathophysiologic relationship between the two glaucoma subtypes.
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Affiliation(s)
- Thanadet Chuangsuwanich
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore, Republic of Singapore.
| | - Tin A Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Republic of Singapore; Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Fabian A Braeu
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Republic of Singapore
| | - Xiaofei Wang
- Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, China
| | - Zhi Yun Chin
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore, Republic of Singapore
| | - Satish Kumar Panda
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore, Republic of Singapore
| | - Martin Buist
- Department of Biomedical Engineering, National University of Singapore, Singapore, Republic of Singapore
| | - Nicholas Strouthidis
- National Institute of Health Research, Biomedical Sciences Centre, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, United Kingdom
| | - Shamira Perera
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Republic of Singapore
| | - Monisha Nongpiur
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Republic of Singapore; Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Republic of Singapore; Duke-NUS Medical School, Singapore, Republic of Singapore
| | - Michaël J A Girard
- Ophthalmic Engineering & Innovation Laboratory, Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore; Duke-NUS Medical School, Singapore, Republic of Singapore; Institute for Molecular and Clinical Ophthalmology, Basel, Switzerland.
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Pardon LP, Greenwald SH, Ferguson CR, Patel NB, Young M, Laurie SS, Macias BR. Identification of Factors Associated With the Development of Optic Disc Edema During Spaceflight. JAMA Ophthalmol 2022; 140:1193-1200. [PMID: 36301519 PMCID: PMC9614681 DOI: 10.1001/jamaophthalmol.2022.4396] [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: 07/05/2022] [Accepted: 09/01/2022] [Indexed: 01/12/2023]
Abstract
Importance Approximately 70% of crew members who complete long-duration missions to the International Space Station develop signs of optic disc edema, a hallmark finding of spaceflight-associated neuro-ocular syndrome. The onset and magnitude of edema differ across individuals, and the reason for this variability remains unknown. Identifying risk factors for spaceflight-induced disc edema is important because this condition may become more severe during extended-duration missions to the moon and Mars and could be associated with irreversible vision loss. Objective To assess whether preflight indicators of crowded optic nerve head morphology, other ocular measures (such as choroid thickness and axial length), body weight, body mass index, sex, age, and previous flight experience are associated with optic disc edema development. Design, Setting, and Participants This cohort study analyzed ocular, body weight, and demographic data collected from 31 US and international crew members before, during, and after spaceflight at the NASA Johnson Space Center and International Space Station. Ocular factors assessed included preflight and in-flight peripapillary total retinal thickness, minimum rim width, optic cup volume, mean cup depth, mean cup width, cup-disc ratio, Bruch membrane opening area, retinal nerve fiber layer thickness, choroid thickness, axial length, and refractive error. In addition, body weight, body mass index, sex, age, and previous spaceflight experience were assessed for associations with optic disc edema development. The data were analyzed from August 2021 to June 2022. Exposure Approximately 6 to 12 months of spaceflight. Main Outcomes and Measures In-flight increases in peripapillary total retinal thickness. Linear mixed models were used to assess for associations between a wide range of risk factors and in-flight increases in peripapillary total retinal thickness, which is a sensitive objective measure for detecting optic disc edema. Results This study included 31 International Space Station crew members with a mean (SD) age of 46.9 (6.0) years (25 men [80.6%]). During spaceflight, mean (SE) peripapillary total retinal thickness increased from 392.0 (5.8) μm to 430.2 (9.6) μm (P < .001), and greater individual changes were associated with smaller preflight cup volume (slope [SE], -62.8 [18.9]; P = .002), shallower preflight cup depth (slope [SE], -0.11 [0.03]; P < .001), and narrower preflight cup width (slope [SE], -0.03 [0.01]; P = .03). No associations were observed between changes in peripapillary total retinal thickness and any other variable evaluated. Conclusions and Relevance Findings of this cohort study suggest that smaller optic cup morphology may be associated with optic disc edema development during spaceflight. Crew members with this cup profile may benefit from enhanced ophthalmic monitoring during spaceflight and use of countermeasures against spaceflight-associated neuro-ocular syndrome.
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Affiliation(s)
| | | | | | | | - Millennia Young
- National Aeronautics and Space Administration Johnson Space Center, Houston, Texas
| | | | - Brandon R. Macias
- National Aeronautics and Space Administration Johnson Space Center, Houston, Texas
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30
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Finite element modeling of effects of tissue property variation on human optic nerve tethering during adduction. Sci Rep 2022; 12:18985. [PMID: 36347907 PMCID: PMC9643519 DOI: 10.1038/s41598-022-22899-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022] Open
Abstract
Tractional tethering by the optic nerve (ON) on the eye as it rotates towards the midline in adduction is a significant ocular mechanical load and has been suggested as a cause of ON damage induced by repetitive eye movements. We designed an ocular finite element model (FEM) simulating 6° incremental adduction beyond the initial configuration of 26° adduction that is the observed threshold for ON tethering. This FEM permitted sensitivity analysis of ON tethering using observed material property variations in measured hyperelasticity of the anterior, equatorial, posterior, and peripapillary sclera; and the ON and its sheath. The FEM predicted that adduction beyond the initiation of ON tethering concentrates stress and strain on the temporal side of the optic disc and peripapillary sclera, the ON sheath junction with the sclera, and retrolaminar ON neural tissue. However, some unfavorable combinations of tissue properties within the published ranges imposed higher stresses in these regions. With the least favorable combinations of tissue properties, adduction tethering was predicted to stress the ON junction and peripapillary sclera more than extreme conditions of intraocular and intracranial pressure. These simulations support the concept that ON tethering in adduction could induce mechanical stresses that might contribute to ON damage.
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Arthur P, Muok L, Nathani A, Zeng EZ, Sun L, Li Y, Singh M. Bioengineering Human Pluripotent Stem Cell-Derived Retinal Organoids and Optic Vesicle-Containing Brain Organoids for Ocular Diseases. Cells 2022; 11:3429. [PMID: 36359825 PMCID: PMC9653705 DOI: 10.3390/cells11213429] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/13/2022] [Accepted: 10/23/2022] [Indexed: 08/24/2023] Open
Abstract
Retinal organoids are three-dimensional (3D) structures derived from human pluripotent stem cells (hPSCs) that mimic the retina's spatial and temporal differentiation, making them useful as in vitro retinal development models. Retinal organoids can be assembled with brain organoids, the 3D self-assembled aggregates derived from hPSCs containing different cell types and cytoarchitectures that resemble the human embryonic brain. Recent studies have shown the development of optic cups in brain organoids. The cellular components of a developing optic vesicle-containing organoids include primitive corneal epithelial and lens-like cells, retinal pigment epithelia, retinal progenitor cells, axon-like projections, and electrically active neuronal networks. The importance of retinal organoids in ocular diseases such as age-related macular degeneration, Stargardt disease, retinitis pigmentosa, and diabetic retinopathy are described in this review. This review highlights current developments in retinal organoid techniques, and their applications in ocular conditions such as disease modeling, gene therapy, drug screening and development. In addition, recent advancements in utilizing extracellular vesicles secreted by retinal organoids for ocular disease treatments are summarized.
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Affiliation(s)
- Peggy Arthur
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
| | - Laureana Muok
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL 32306, USA
| | - Aakash Nathani
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
| | - Eric Z. Zeng
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL 32306, USA
| | - Li Sun
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL 32306, USA
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Yan Li
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL 32306, USA
| | - Mandip Singh
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
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Karimi A, Razaghi R, Rahmati SM, Girkin CA, Downs JC. Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues. Invest Ophthalmol Vis Sci 2022; 63:14. [PMID: 36255364 PMCID: PMC9587471 DOI: 10.1167/iovs.63.11.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 09/27/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose The laminar region of the optic nerve head (ONH), thought to be the site of damage to the retinal ganglion cell axons in glaucoma, is continuously loaded on its anterior and posterior surfaces by dynamic intraocular pressure (IOP) and orbital cerebrospinal fluid pressure (CSFP), respectively. Thus, translaminar pressure (TLP; TLP = IOP-CSFP) has been proposed as a glaucoma risk factor. Methods Three eye-specific finite element models of the posterior human eye were constructed, including full 3D microstructures of the load-bearing lamina cribrosa (LC) with interspersed laminar neural tissues (NTs), and heterogeneous, anisotropic, hyperelastic material formulations for the surrounding peripapillary sclera and adjacent pia. ONH biomechanical responses were simulated using three combinations of IOP and CSFP loadings consistent with posture change from sitting to supine. Results Results show that tensile, compressive, and shear stresses and strains in the ONH were higher in the supine position compared to the sitting position (P < 0.05). In addition, LC beams bear three to five times more TLP-driven stress than interspersed laminar NT, whereas laminar NT exhibit three to five times greater strain than supporting LC (P < 0.05). Compared with CSFP, IOP drove approximately four times greater stress and strain in the LC, NT, and peripapillary sclera, normalized per mm Hg pressure change. In addition, IOP drove approximately three-fold greater scleral canal expansion and anterior-posterior laminar deformation than CSFP per mm Hg (P < 0.05). Conclusions Whereas TLP has been hypothesized to play a prominent role in ONH biomechanics, the IOP and CSFP effects are not equivalent, as IOP-driven stress, strain, and deformation play a more dominant role than CSFP effects.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Reza Razaghi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | | | - Christopher A. Girkin
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - J. Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
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Chou CC, Shih PJ, Wang CY, Jou TS, Chen JP, Wang IJ. Corvis Biomechanical Factor Facilitates the Detection of Primary Angle Closure Glaucoma. Transl Vis Sci Technol 2022; 11:7. [PMID: 36180025 PMCID: PMC9547358 DOI: 10.1167/tvst.11.10.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To characterize the corneal biomechanical properties of primary angle closure glaucoma (PACG) and to investigate the diagnostic performance of combining corneal biomechanical parameters and anterior segment parameters in detecting PACG. Methods This retrospective cross-sectional study evaluated 79 and 81 eyes of normal controls and patients with PACG, respectively. Corvis Biomechanical Factor (CBiF) and anterior chamber volume (ACV) were measured using the Corvis ST and Pentacam, respectively. We performed multivariable logistic regression, adjusted for age, sex, central corneal thickness, intraocular pressure, and ACV to evaluate the effect of CBiF on PACG. The area under the receiver operating curve (AUC) was calculated to compare the diagnostic performance of ACV, CBiF, and ACV-CBiF combination for detecting PACG. Results The median CBiF of the control and PACG groups was 6.61 (interquartile range [IQR], 6.39–6.88) and 6.20 (IQR, 5.93–6.48), respectively (P < 0.001). A lower CBiF, suggestive of decreased corneal biomechanical stability, increased the odds of PACG (odds ratio, 0.029; 95% confidence interval [CI], 0.003–0.266; P = 0.002) in the multivariable logistic regression model. The ACV–CBiF combination yielded the highest AUC (0.934; 95% CI, 0.882–0.968) compared with ACV alone (0.878; 95% CI, 0.823–0.928). The ACV-CBiF combination had significantly higher discriminatory ability than that of ACV alone (DeLong test, P = 0.004). Conclusions Lower CBiF and ACV may act as independent predictors for PACG. Combining ACV and CBiF may enhance detection of PACG. Translational Relevance The combination of corneal biomechanical parameters and anterior segment parameters enhances the detection of PACG.
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Affiliation(s)
- Chien-Chih Chou
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Ophthalmology, Taichung Veterans General Hospital, Taichung, Taiwan.,School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Po-Jen Shih
- Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Chun-Yuan Wang
- Department of Ophthalmology, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Tzuu-Shuh Jou
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jun-Peng Chen
- Biostatistics Task Force of Taichung Veterans General Hospital, Taichung, Taiwan
| | - I-Jong Wang
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan.,Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
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Ohn K, Noh YH, Moon JI, Jung Y. Measurement of corneal biomechanical properties in diabetes mellitus using the Corvis ST. Medicine (Baltimore) 2022; 101:e30248. [PMID: 36086751 PMCID: PMC10980441 DOI: 10.1097/md.0000000000030248] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 07/13/2022] [Indexed: 11/26/2022] Open
Abstract
We sought to assess changes in corneal biomechanical parameters in patients with diabetes mellitus (DM) in comparison with those among healthy controls using Corvis ST (CST). The study group included 209 eyes from healthy control subjects and 33 eyes from diabetic subjects, respectively. Following an ophthalmological examination, measurements with CST were taken. Additionally, hemoglobin A1c and blood glucose values were collected. Results were then compared to those of the control group after adjusting for potential confounding factors, including age-, intraocular pressure (IOP)-, central corneal thickness (CCT)-, spherical equivalent (SE)- and axial length (AL). After adjusting for potential confounding factors, including the age, IOP, CCT, SE, and AL, patients with DM presented significantly lower whole-eye movement (WEM) (ms) values than patients without DM (21.71 ± 0.84 vs. 22.15 ± 0.64 ms; P < .001). There was a significant and negative correlation between WEM (ms) and hemoglobin A1c in DM patients (r = -0.733; P = .001). In univariate and multivariate general linear mixed model (GLMM) analyses, IOP (P < .001 and P < .001, respectively) and the presence of DM (P = .001 and P < .001, respectively) significantly affected WEM (ms). In DM, significant changes in corneal biomechanical properties were detectable. The DM group showed significantly less deformable cornea and sclera than did the normal controls, even after adjusting for age, IOP, CCT, SE, and AL. These findings may cause misinterpretation of IOP measurements in diabetic patients. Therefore, the measurement of corneal biomechanics should be taken into consideration in clinical practice.
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Affiliation(s)
- Kyoung Ohn
- Department of Ophthalmology, Yeouido St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Young Ho Noh
- Department of Ophthalmology, Yeouido St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jung Il Moon
- Department of Ophthalmology, Yeouido St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Younhea Jung
- Department of Ophthalmology, Yeouido St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Li M, Luo Z, Yan X, Chen Z. The Anterior Segment Biometrics in High Myopia Eyes. Ophthalmic Res 2022; 66:75-85. [PMID: 35926453 DOI: 10.1159/000526280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/20/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION The aim of this study was to investigate and compare the anterior segment biometrics in high myopia and control groups. METHODS Thirty-four eyes of 34 high myopia patients and 42 eyes of 42 control subjects were included. Schlemm's canal (SC) area, trabecular meshwork (TM) thickness and length, scleral spur (SS) length, and anterior scleral thickness (AST) were measured using swept-source optical coherence tomography. Associations between SC area, TM thickness, TM length, SS length, and AST were also estimated. RESULTS SC area, TM thickness, and SS length were significantly associated with AST0 (AST at 0 mm from SS) in both high myopia and control groups. AST0 (702.61 ± 78.05 vs. 729.12 ± 95.87 μm, p = 0.085) and SS length (206.25 ± 52.25 vs. 212.09 ± 51.86 μm, p = 0.556) were not significantly different between high myopia and control groups, whereas SC area (6,622.68 ± 1,130.06 vs. 6,105.85 ± 1,297.84 μm2, p = 0.015) was significantly greater and TM thickness (96.15 ± 34.40 vs. 107.93 ± 29.97 μm, p = 0.048) was significantly thinner in high myopia group than in control group. CONCLUSION SC area and TM thickness were significantly associated with AST0, while AST0 and SS length were not significantly different between high myopia and control groups. The changes in SC and TM dimensions in high myopia eyes might be caused by factors other than AST0 and SS length.
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Affiliation(s)
- Mu Li
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhaoxia Luo
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoqin Yan
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiqi Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Kamalipour A, Moghimi S, Eslani M, Nishida T, Mohammadzadeh V, Micheletti E, Girkin CA, Fazio MA, Liebmann JM, Zangwill LM, Weinreb RN. A Prospective Longitudinal Study to Investigate Corneal Hysteresis as a Risk Factor of Central Visual Field Progression in Glaucoma. Am J Ophthalmol 2022; 240:159-169. [PMID: 35278360 PMCID: PMC10249485 DOI: 10.1016/j.ajo.2022.02.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/07/2022] [Accepted: 02/27/2022] [Indexed: 11/22/2022]
Abstract
PURPOSE To evaluate the role of corneal hysteresis (CH) as a risk factor of central visual field (VF) progression in a cohort of glaucoma suspect and glaucoma patients. DESIGN Prospective cohort study. METHODS Two hundred forty-eight eyes of 143 subjects who were followed for an average of 4.8 years with a minimum of 5 visits with 10-2 and 24-2 VF tests were included. Univariable and multivariable linear mixed-effects models were used to identify characteristics associated with the rate of change over time in 10-2 and 24-2 mean deviation (MD). Mixed-effects logistic regression was used to evaluate characteristics associated with an increased likelihood of event-based 10-2 VF progression based on the clustered pointwise linear regression criterion. RESULTS CH was significantly associated with 10-2 and 24-2 VF progression in the univariable trend-based analysis. In multivariable trend-based analyses, lower CH was associated with a faster rate of decline in 10-2 MD (0.07 dB/y per 1 mm Hg, P < .001) but not with 24-2 MD (P = .490). In multivariable event-based analysis, lower CH was associated with an increased likelihood of 10-2 VF progression (odds ratio = 1.35 per 1 mm Hg lower, P = .025). Similar results were found in eyes with early glaucomatous damage at the baseline (baseline: 24-2 MD ≥ -6 dB). CONCLUSIONS Lower CH was associated with a statistically significant, but relatively small, increased risk of central VF progression on the 10-2 test grid. Given the substantial influence of central VF impairment on the quality of life, clinicians should consider using CH to assess the risk of progression in patients with primary open-angle glaucoma including those with early disease.
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Affiliation(s)
- Alireza Kamalipour
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Sasan Moghimi
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Medi Eslani
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Takashi Nishida
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Vahid Mohammadzadeh
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Eleonora Micheletti
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California
| | | | - Massimo A Fazio
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California; Department of Ophthalmology and Visual Sciences, Heersink School of Medicine; Department of Biomedical Engineering, School of Engineering
| | - Jeffrey M Liebmann
- University of Alabama at Birmingham, Alabama, and Bernard and Shirlee Brown Glaucoma Research Laboratory, Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York, New York, USA
| | - Linda M Zangwill
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California.
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Hua Y, Lu Y, Walker J, Lee PY, Tian Q, McDonald H, Pallares P, Ji F, Brazile BL, Yang B, Voorhees AP, Sigal IA. Eye-specific 3D modeling of factors influencing oxygen concentration in the lamina cribrosa. Exp Eye Res 2022; 220:109105. [PMID: 35568202 PMCID: PMC11007759 DOI: 10.1016/j.exer.2022.109105] [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: 12/21/2021] [Revised: 04/06/2022] [Accepted: 04/28/2022] [Indexed: 11/29/2022]
Abstract
Our goal was to identify the factors with the strongest influence on the minimum lamina cribrosa (LC) oxygen concentration as potentially indicative of conditions increasing hypoxia risk. Because direct measurement of LC hemodynamics and oxygenation is not yet possible, we developed 3D eye-specific LC vasculature models. The vasculature of a normal monkey eye was perfusion-labeled post-mortem. Serial cryosections through the optic nerve head were imaged using fluorescence and polarized light microscopy to visualize the vasculature and collagen, respectively. The vasculature within a 450 μm-thick region containing the LC - identified from the collagen, was segmented, skeletonized, and meshed for simulations. Using Monte Carlo sampling, 200 vascular network models were generated with varying vessel diameter, neural tissue oxygen consumption rate, inflow hematocrit, and blood pressures (arteriole, venule, anterior boundary, and posterior boundary). Factors were varied over ranges of baseline ±20% with uniform probability. For each model we first obtained the blood flow, and from this the neural tissue oxygen concentration. ANOVA was used to identify the factors with the strongest influence on the minimum (10th percentile) oxygen concentration in the LC. The three most influential factors were, in ranked order, vessel diameter, neural tissue oxygen consumption rate, and arteriole pressure. There was a strong interaction between vessel diameter and arteriole pressure whereby the impact of one factor was larger when the other factor was small. Our results show that, for the eye analyzed, conditions that reduce vessel diameter, such as vessel compression due to elevated intraocular pressure or gaze-induced tissue deformation, may particularly contribute to decreased LC oxygen concentration. More eyes must be analyzed before generalizing.
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Affiliation(s)
- Yi Hua
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Yuankai Lu
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jason Walker
- Department of Biological Science, University of Pittsburgh, Pittsburgh, PA, United States
| | - Po-Yi Lee
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Qi Tian
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Haiden McDonald
- Department of Biological Science, University of Pittsburgh, Pittsburgh, PA, United States
| | - Pedro Pallares
- Department of Biological Science, University of Pittsburgh, Pittsburgh, PA, United States
| | - Fengting Ji
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Bryn L Brazile
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Bin Yang
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Engineering, Rangos School of Health Sciences, Duquesne University, Pittsburgh, PA, United States
| | - Andrew P Voorhees
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ian A Sigal
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.
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Jo AO, Lakk M, Rudzitis CN, Križaj D. TRPV4 and TRPC1 channels mediate the response to tensile strain in mouse Müller cells. Cell Calcium 2022; 104:102588. [PMID: 35398674 PMCID: PMC9119919 DOI: 10.1016/j.ceca.2022.102588] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/10/2022] [Accepted: 04/01/2022] [Indexed: 11/24/2022]
Abstract
Müller glia, a pillar of metabolic, volume regulatory and immune/inflammatory signaling in the mammalian retina, are among the earliest responders to mechanical stressors in the eye. Ocular trauma, edema, detachment and glaucoma evoke early inflammatory activation of Müller cells yet the identity of their mechanotransducers and signaling mechanisms downstream remains unknown. Here, we investigate expression of genes that encode putative stretch-activated calcium channels (SACs) in mouse Müller cells and study their responses to dynamical tensile loading in cells loaded with a calcium indicator dye. Transcript levels in purified glia were Trpc1>Piezo1>Trpv2>Trpv4>>Trpv1>Trpa1. Cyclic radial deformation of matrix-coated substrates produced dose-dependent increases in [Ca2+]i that were suppressed by the TRPV4 channel antagonist HC-067047 and by ablation of the Trpv4 gene. Stretch-evoked calcium responses were also reduced by knockdown and pharmacological inhibition of TRPC1 channels whereas the TRPV2 inhibitor tranilast had no effect. These data demonstrate that Müller cells are intrinsically mechanosensitive, with the response to tensile loading mediated through synergistic activation of TRPV4 and TRPC1 channels. Coupling between mechanical stress and Müller Ca2+ homeostasis has treatment implications, since many neuronal injury paradigms in the retina involve calcium dysregulation associated with inflammatory and immune signaling.
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Affiliation(s)
- Andrew O Jo
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Christopher N Rudzitis
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132; Interdepartmental Program in Neuroscience
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132; Interdepartmental Program in Neuroscience; Department of Neurobiology, University of Utah, Salt Lake City, UT 84112; Department of Bioengineering, University of Utah, Salt Lake City, UT 84112.
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Marques R, Andrade De Jesus D, Barbosa-Breda J, Van Eijgen J, Stalmans I, van Walsum T, Klein S, G Vaz P, Sánchez Brea L. Automatic Segmentation of the Optic Nerve Head Region in Optical Coherence Tomography: A Methodological Review. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 220:106801. [PMID: 35429812 DOI: 10.1016/j.cmpb.2022.106801] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 03/07/2022] [Accepted: 04/01/2022] [Indexed: 06/14/2023]
Abstract
The optic nerve head (ONH) represents the intraocular section of the optic nerve, which is prone to damage by intraocular pressure (IOP). The advent of optical coherence tomography (OCT) has enabled the evaluation of novel ONH parameters, namely the depth and curvature of the lamina cribrosa (LC). Together with the Bruch's membrane minimum-rim-width (BMO-MRW), these seem to be promising ONH parameters for diagnosis and monitoring of retinal diseases such as glaucoma. Nonetheless, these OCT derived biomarkers are mostly extracted through manual segmentation, which is time-consuming and prone to bias, thus limiting their usability in clinical practice. The automatic segmentation of ONH in OCT scans could further improve the current clinical management of glaucoma and other diseases. This review summarizes the current state-of-the-art in automatic segmentation of the ONH in OCT. PubMed and Scopus were used to perform a systematic review. Additional works from other databases (IEEE, Google Scholar and ARVO IOVS) were also included, resulting in a total of 29 reviewed studies. For each algorithm, the methods, the size and type of dataset used for validation, and the respective results were carefully analysed. The results show a lack of consensus regarding the definition of segmented regions, extracted parameters and validation approaches, highlighting the importance and need of standardized methodologies for ONH segmentation. Only with a concrete set of guidelines, these automatic segmentation algorithms will build trust in data-driven segmentation models and be able to enter clinical practice.
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Affiliation(s)
- Rita Marques
- Laboratory for Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UC), Department of Physics, University of Coimbra, Coimbra, Portugal; Biomedical Imaging Group Rotterdam, Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands
| | - Danilo Andrade De Jesus
- Biomedical Imaging Group Rotterdam, Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands.
| | - João Barbosa-Breda
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium; Cardiovascular R&D Center, Faculty of Medicine of the University of Porto, Porto, Portugal; Ophthalmology Department, São João Universitary Hospital Center, Porto, Portugal
| | - Jan Van Eijgen
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium; Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium
| | - Ingeborg Stalmans
- Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium; Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium
| | - Theo van Walsum
- Biomedical Imaging Group Rotterdam, Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands
| | - Stefan Klein
- Biomedical Imaging Group Rotterdam, Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands
| | - Pedro G Vaz
- Laboratory for Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UC), Department of Physics, University of Coimbra, Coimbra, Portugal
| | - Luisa Sánchez Brea
- Biomedical Imaging Group Rotterdam, Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, Netherlands
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Finite Element Analysis of Cornea and Lid Wiper during Blink, with and without Contact Lens. J Ophthalmol 2022; 2022:7930334. [PMID: 35620413 PMCID: PMC9129998 DOI: 10.1155/2022/7930334] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 04/26/2022] [Indexed: 11/18/2022] Open
Abstract
Ocular surface disorders such as Lid Wiper Epitheliopathy (LWE), Superior Epithelial Arcuate Lesion (SEAL), and contact lens-induced Limbal Stem Cell Deficiency (LSCD) as well as Superior Limbic Keratoconjunctivitis (SLK) affect one’s quality of life. Hence, it is imperative to investigate the underlying causes of these ocular surface disorders. During blink, the undersurface of the eyelid tends to interact with the cornea and the conjunctiva. The presence of a contact lens can add to the biomechanical frictional changes on these surfaces. To estimate these changes with and without a contact lens, a finite element model (FEM) of the eyelid wiper, eyeball, and contact lens was developed using COMSOL Multiphysics. Biomechanical properties such as von Mises stress (VMS) and displacement were calculated. Our study concluded that (a) maximum VMS was observed in the lid wiper in the absence of contact lens in the eye and (b) maximum VMS was observed in the superior 1.3 mm of the cornea in the presence of the contact lens in the eye. Thus, the development of friction-induced ocular surface disorders such as LWE, SLK, SEAL, and LSCD could be attributed to increased VMS. FEA is a useful simulation tool that helps us to understand the effect of blink on a normal eye with and without CL.
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Gerberich BG, Hannon BG, Brown DM, Read AT, Ritch MD, Schrader Echeverri E, Nichols L, Potnis C, Sridhar S, Toothman MG, Schwaner SA, Winger EJ, Huang H, Gershon GS, Feola AJ, Pardue MT, Prausnitz MR, Ethier CR. Evaluation of Spatially Targeted Scleral Stiffening on Neuroprotection in a Rat Model of Glaucoma. Transl Vis Sci Technol 2022; 11:7. [PMID: 35536721 PMCID: PMC9100482 DOI: 10.1167/tvst.11.5.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/14/2022] [Indexed: 11/25/2022] Open
Abstract
Purpose Scleral stiffening may protect against glaucomatous retinal ganglion cell (RGC) loss or dysfunction associated with ocular hypertension. Here, we assess the potential neuroprotective effects of two treatments designed to stiffen either the entire posterior sclera or only the sclera adjacent to the peripapillary sclera in an experimental model of glaucoma. Methods Rat sclerae were stiffened in vivo using either genipin (crosslinking the entire posterior sclera) or a regionally selective photosensitizer, methylene blue (stiffening only the juxtaperipapillary region surrounding the optic nerve). Ocular hypertension was induced using magnetic microbeads delivered to the anterior chamber. Morphological and functional outcomes, including optic nerve axon count and appearance, retinal thickness measured by optical coherence tomography, optomotor response, and electroretinography traces, were assessed. Results Both local (juxtaperipapillary) and global (whole posterior) scleral stiffening treatments were successful at increasing scleral stiffness, but neither provided demonstrable neuroprotection in hypertensive eyes as assessed by RGC axon counts and appearance, optomotor response, or electroretinography. There was a weak indication that scleral crosslinking protected against retinal thinning as assessed by optical coherence tomography. Conclusions Scleral stiffening was not demonstrated to be neuroprotective in ocular hypertensive rats. We hypothesize that the absence of benefit may in part be due to RGC loss associated with the scleral stiffening agents themselves (mild in the case of genipin, and moderate in the case of methylene blue), negating any potential benefit of scleral stiffening. Translational Relevance The development of scleral stiffening as a neuroprotective treatment will require the identification of better tolerated stiffening protocols and further preclinical testing.
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Affiliation(s)
- Brandon G. Gerberich
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Bailey G. Hannon
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Dillon M. Brown
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - A. Thomas Read
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Matthew D. Ritch
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Elisa Schrader Echeverri
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Lauren Nichols
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Cahil Potnis
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veteran Affairs Healthcare System, Atlanta, GA, USA
| | - Sreesh Sridhar
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Maya G. Toothman
- College of Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Stephen A. Schwaner
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- Exponent, Inc., Biomechanics Practice, Atlanta, GA, USA
| | - Erin J. Winger
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Hannah Huang
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Gabby S. Gershon
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Andrew J. Feola
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veteran Affairs Healthcare System, Atlanta, GA, USA
| | - Machelle T. Pardue
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veteran Affairs Healthcare System, Atlanta, GA, USA
| | - Mark R. Prausnitz
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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Guo L, Hua R, Zhang X, Yan TY, Tong Y, Zhao X, Chen SC, Wang M, Bressler NM, Kong J. Scleral Cross-Linking in Form-Deprivation Myopic Guinea Pig Eyes Leads to Glaucomatous Changes. Invest Ophthalmol Vis Sci 2022; 63:24. [PMID: 35594036 PMCID: PMC9150827 DOI: 10.1167/iovs.63.5.24] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 03/06/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the potential glaucomatous changes caused by scleral cross-linking (CXL) in a guinea pig form-deprivation (FD) myopia model. Methods Eighty 4-week-old tricolor guinea pigs were divided into four groups: FD only, genipin CXL only, FD plus CXL, and control. Refractive error, axial length (AL), intraocular pressure (IOP), and structural and vasculature optic disc changes in optical coherence tomography (OCT) and OCT angiography (OCTA) were measured at baseline and day 21. CXL efficacy was evaluated by scleral rigidity Young's modulus values. Histological and molecular changes in the anterior chamber angle, retina, and sclera were assessed. Results Baseline parameters were similar among groups (P > 0.05). The FD plus CXL group at day 21 had the least increase of AL (0.14 ± 0.08 mm) and highest IOP elevation (31.5 ± 3.6 mmHg) compared with the FD-only group (AL: 0.68 ± 0.17 mm; IOP: 22.2 ± 2.6 mmHg) and the control group (AL: 0.24 ± 0.09 mm; IOP: 17.4 ± 1.8 mmHg) (all P < 0.001). OCT and OCTA parameters of the optic disc in the FD plus CXL group at day 21 showed glaucomatous changes and decreased blood flow signals. Sclera rigidity increased in the CXL and FD plus CXL groups. Advanced glycation end products deposited extensively in the retina, choroid, and sclera of FD plus CXL eyes. Conclusions CXL causes increased IOP and subsequent optic disc, anterior segment, and scleral changes while inhibiting myopic progression and axial elongation in FD guinea pig eyes. Therefore, applying CXL to control myopia raises safety concerns.
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Affiliation(s)
- Lei Guo
- Department of Ophthalmology, the Fourth Hospital of China Medical University, Shenyang, China
- Ophthalmology and Optometry Center, the First Hospital of China Medical University, Shenyang, China
| | - Rui Hua
- Department of Ophthalmology, the First Hospital of China Medical University, Shenyang, China
| | - Xinxin Zhang
- Department of Ophthalmology, the Fourth Hospital of China Medical University, Shenyang, China
| | - Ting Yu Yan
- Department of Ophthalmology, the Fourth People's Hospital of Shenyang, Shenyang, China
| | - Yang Tong
- Ocular Pharmacology Laboratory, Shenyang Xingqi Eye Hospital, Shenyang, China
| | - Xin Zhao
- Ocular Pharmacology Laboratory, Shenyang Xingqi Eye Hospital, Shenyang, China
| | - Shi Chao Chen
- Ocular Pharmacology Laboratory, Shenyang Xingqi Eye Hospital, Shenyang, China
| | - Moying Wang
- Department of Ophthalmology, the Fourth Hospital of China Medical University, Shenyang, China
| | - Neil M. Bressler
- Retina Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Jun Kong
- Department of Ophthalmology, the Fourth Hospital of China Medical University, Shenyang, China
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Gerberich BG, Wood-Yang AJ, Radmand A, Nichols LM, Hejri A, Echeverri ES, Gersch HG, Prausnitz MR. Computational modeling of corneal and scleral collagen photocrosslinking. J Control Release 2022; 347:314-329. [PMID: 35513208 DOI: 10.1016/j.jconrel.2022.04.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/21/2022] [Accepted: 04/27/2022] [Indexed: 11/28/2022]
Abstract
Scleral photocrosslinking is increasingly investigated for treatment of myopia and glaucoma. In this study a computational model was developed to predict crosslinking efficiency of visible/near infrared photosensitizers in the sclera. Photocrosslinking was validated against riboflavin corneal crosslinking experimental studies and subsequently modeled for the sensitizer, methylene blue, administered by retrobulbar injection to the posterior sclera and irradiated with a transpupillary light beam. Optimal ranges were determined for treatment parameters including light intensity, methylene blue concentration, injection volume, and inspired oxygen concentration. Additionally, sensitivity of crosslinking to various parameters was quantified. The most sensitive parameters (in order of greatest to least sensitive) were tissue parameters (including scleral thickness and choroidal melanin concentration), treatment parameters (including treatment duration and inspired oxygen concentration), and sensitizer parameters (including triplet quantum yield).
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Affiliation(s)
- Brandon G Gerberich
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Amy J Wood-Yang
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Afsane Radmand
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Lauren M Nichols
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Amir Hejri
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Elisa Schrader Echeverri
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Hannah G Gersch
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Mark R Prausnitz
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia.
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Feola AJ, Girkin CA, Ethier CR, Samuels BC. A Potential Role of Acute Choroidal Expansion in Nonarteritic Anterior Ischemic Optic Neuropathy. Invest Ophthalmol Vis Sci 2022; 63:23. [PMID: 35481840 PMCID: PMC9055550 DOI: 10.1167/iovs.63.4.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Nonarteritic anterior ischemic optic neuropathy (NAION) has been associated with a thickened choroid at the optic nerve head (ONH). Here, we use computational modeling to better understand how choroidal expansion and choroidal geometry influence tissue deformation within the ONH relative to intraocular pressure (IOP) and intracranial pressure (ICP) effects. Methods Using a model of the posterior eye that included the sclera, peripapillary sclera, annular ring, pia mater, dura mater, neural tissues, Bruch's membrane, choroid, and lamina cribrosa, we examined how varying material properties of ocular tissues influenced ONH deformations under physiological and supra-physiological, or “pathological,” conditions. We considered choroidal expansion (c. 35 µL of expansion), elevated IOP (30 mm Hg), and elevated ICP (20 mm Hg), and calculated peak strains in the ONH relative to a baseline condition representing an individual in the upright position. Results Supra-physiological choroidal expansion had the largest impact on strains in the prelaminar neural tissue. In addition, compared to a tapered choroid, a “blunt” choroid insertion at the ONH resulted in higher strains. Elevated IOP and ICP caused the highest strains within the lamina cribrosa and retrolaminar neural tissue, respectively. Conclusions Acute choroidal expansion caused large deformations of the ONH and these deformations were impacted by choroid geometry. These results are consistent with the concept that compartment syndrome due to the choroid geometry and/or expansion at the ONH contributes to NAION. Prolonged deformations due to supra-physiological loading may induce a mechanobiological response or ischemia, highlighting the potential impact of choroidal expansion on biomechanical strains in the ONH.
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Affiliation(s)
- Andrew J Feola
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Atlanta, Georgia, United States.,Department of Ophthalmology, Emory Eye Center, Emory University School of Medicine, Atlanta, Georgia, United States.,Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, United States
| | - Christopher A Girkin
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - C Ross Ethier
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, United States
| | - Brian C Samuels
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States
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Abstract
PURPOSE OF REVIEW Biomechanics is an important aspect of the complex family of diseases known as the glaucomas. Here, we review recent studies of biomechanics in glaucoma. RECENT FINDINGS Several tissues have direct and/or indirect biomechanical roles in various forms of glaucoma, including the trabecular meshwork, cornea, peripapillary sclera, optic nerve head/sheath, and iris. Multiple mechanosensory mechanisms and signaling pathways continue to be identified in both the trabecular meshwork and optic nerve head. Further, the recent literature describes a variety of approaches for investigating the role of tissue biomechanics as a risk factor for glaucoma, including pathological stiffening of the trabecular meshwork, peripapillary scleral structural changes, and remodeling of the optic nerve head. Finally, there have been advances in incorporating biomechanical information in glaucoma prognoses, including corneal biomechanical parameters and iridial mechanical properties in angle-closure glaucoma. SUMMARY Biomechanics remains an active aspect of glaucoma research, with activity in both basic science and clinical translation. However, the role of biomechanics in glaucoma remains incompletely understood. Therefore, further studies are indicated to identify novel therapeutic approaches that leverage biomechanics. Importantly, clinical translation of appropriate assays of tissue biomechanical properties in glaucoma is also needed.
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Affiliation(s)
- Babak N. Safa
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta GA, USA
| | - Cydney A. Wong
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta GA, USA
| | - Jungmin Ha
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta GA, USA
| | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta GA, USA
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Fang D, Wang L, Chen L, Liang J, Li K, Mao X, Xie T, Zhang S. Vitreomacular Interface Abnormalities in Myopic Foveoschisis: Correlation With Morphological Features and Outcome of Vitrectomy. Front Med (Lausanne) 2022; 8:796127. [PMID: 35071276 PMCID: PMC8766811 DOI: 10.3389/fmed.2021.796127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To compare the morphologic characteristics and response to surgery of myopic foveoschisis (MF) with different patterns of vitreomacular interface abnormalities (VMIAs). Methods: In this observational case series, 158 eyes of 121 MF patients with epiretinal membrane (ERM) or vitreomacular traction (VMT) based on optical coherence tomography (OCT) were enrolled. All the eyes were divided into two groups by the pattern of VMIAs: ERM and VMT group. Sixty-one eyes underwent pars plana vitrectomy (PPV) and were followed up for at least 6 months. The morphologic characteristics based on OCT and the surgical outcome were evaluated. Outcome: ERM and VMT were found in 47.47 and 52.53% of the cases, respectively. A higher rate of foveal detachment (61.4 vs. 26.7%; p < 0.001) and a higher rate of outer lamellar macular hole (45.8 vs. 21.3%; p = 0.001) were detected in the eyes with VMT compared with those with ERM. In contrast, a lower rate of inner lamellar macular hole (28.9 vs. 60.0%; p = 0.001) was detected in the eyes with VMT compared with those with ERM. The disruption of the external limiting membrane (ELM) was more common in the eyes with VMT than in those with ERM (45.8 vs. 21.3%; p = 0.001). PPV was performed in 61 eyes with a mean follow-up time of 23.55 ± 19.92 months. After surgery, anatomical resolution was achieved in 51 eyes (83.6%). At the final visit, the mean central foveal thickness (CFT) decreased significantly from 547.83 to 118.74 μm, and the mean LogMAR BCVA improved significantly from 0.92 to 0.57. The VMT group was associated with a higher proportion of eyes with visual acuity improvement postoperatively (p = 0.02) and had more a decrease of CFT (P = 0.007) compared with the ERM group. Conclusion: In the eyes with MF, outer retinal lesions occurred more frequently in the eyes with VMT, whereas inner retinal lesions occurred more frequently in the eyes with ERM. Tangential force generated by ERM may act as a causative factor for the inner retinal lesions in MF, and inward-directed force resulting from VMT may act as a causative factor for outer retinal lesions in MF.
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Affiliation(s)
- Dong Fang
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Jinan University, Shenzhen, China
| | - Li Wang
- Department of Ophthalmology, Chengdu Second People's Hospital, Chengdu, China
| | - Lu Chen
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Jinan University, Shenzhen, China
| | - Jia Liang
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Jinan University, Shenzhen, China
| | - Kunke Li
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Jinan University, Shenzhen, China
| | - Xingxing Mao
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Jinan University, Shenzhen, China
| | - Ting Xie
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Jinan University, Shenzhen, China
| | - Shaochong Zhang
- Shenzhen Eye Hospital, Shenzhen Key Laboratory of Ophthalmology, Jinan University, Shenzhen, China
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Yan X, Li M, Chen Z, Zhou X. The anterior scleral thickness in eyes with primary open-angle glaucoma. Graefes Arch Clin Exp Ophthalmol 2022; 260:1601-1610. [PMID: 35067770 PMCID: PMC9007782 DOI: 10.1007/s00417-021-05523-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 12/07/2021] [Accepted: 12/14/2021] [Indexed: 11/24/2022] Open
Abstract
Abstract
Purpose
To investigate the anterior scleral thickness (AST) and its associations with Schlemm’s canal (SC) area, trabecular meshwork (TM) thickness and length, and scleral spur (SS) length in healthy and primary open-angle glaucoma (POAG) groups.
Methods
Thirty-five eyes of 35 healthy subjects and 23 eyes of 23 patients with POAG were included. The AST, SC area, TM thickness and length, and SS length were measured using swept-source optical coherence tomography. AST was measured at 0 mm (AST0), 1 mm (AST1), 2 mm (AST2), and 3 mm (AST3) from SS. Associations between AST and SC area, TM thickness and length, and SS length were also estimated.
Results
AST0 (728.84 ± 99.33 vs. 657.39 ± 67.02 μm, p < 0.001), AST1 (537.79 ± 79.55 vs. 506.83 ± 57.37 μm, p = 0.038), AST3 (571.09 ± 79.15 vs. 532.13 ± 59.84 μm, p = 0.009), SC area (6304.26 ± 1238.72 vs. 4755.64 ± 1122.71 μm2, p < 0.001), TM thickness (107.21 ± 31.26 vs. 94.51 ± 24.18 μm, p = 0.035), TM length (736.20 ± 141.85 vs. 656.43 ± 127.03 μm, p = 0.004), and SS length (219.89 ± 50.29 vs. 174.54 ± 35.58 μm, p < 0.001) were significantly greater in healthy group than in POAG group. In addition, SC area, TM thickness, and SS length were significantly and positively associated with AST0 in the healthy group, whereas no similar associations were observed in the POAG group.
Conclusions
Compared with the healthy group, AST was significantly thinner in the POAG group, which also had smaller SC and TM dimensions. Moreover, the SC area, TM thickness, and SS length were significantly and positively associated with AST in the healthy group. Thus, AST might play an important role in maintaining TM and SC morphology and further in the pathogenesis of POAG.
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Affiliation(s)
- Xiaoqin Yan
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Mu Li
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Zhiqi Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiongwu Zhou
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Choi YJ, Lee EJ. The Effects of Anti-glaucoma Eyedrops on Corneal Hysteresis in Patients with Open-angle Glaucoma and Glaucoma-suspect. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2022. [DOI: 10.3341/jkos.2022.63.1.51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Purpose: We explored the effects of topical anti-glaucoma medications on the corneal biochemical properties of patients with open-angle glaucoma (OAG) and glaucoma suspect (GS patients).Methods: We retrospectively reviewed data on 115 OAG and 98 GS patients (225 and 128 eyes respectively). Corneal hysteresis (CH) was measured using an ocular response analyzer. Factors influencing CH were determined using a generalized estimation equation.Results: The mean CH was lower in OAG than GS patients (p < 0.001). A lower cornea-compensated intraocular pressure, concomitant use of a beta-adrenergic blocker and an alpha2-adrenergic agonist, a higher visual field mean deviation, and a larger central corneal thickness were associated with a higher CH in the OAG group.Conclusions: Concomitant use of a topical beta-adrenergic blocker and an alpha2-adrenergic agonist was associated with a higher CH.
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Kwok S, Pan M, Hazen N, Pan X, Liu J. Mechanical Deformation of Peripapillary Retina in Response to Acute Intraocular Pressure Elevation. J Biomech Eng 2022; 144:1131131. [PMID: 35001106 DOI: 10.1115/1.4053450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Indexed: 11/08/2022]
Abstract
Elevated intraocular pressure (IOP) may cause mechanical injuries to the optic nerve head (ONH) and the peripapillary tissues in glaucoma. Previous studies have reported the mechanical deformation of the ONH and the peripapillary sclera (PPS) at elevated IOP. The deformation of the peripapillary retina (PPR) has not been well-characterized. Here we applied high-frequency ultrasound elastography to map and quantify PPR deformation, and compared PPR, PPS and ONH deformation in the same eye. Whole globe inflation was performed in ten human donor eyes. High-frequency ultrasound scans of the posterior eye were acquired while IOP was raised from 5 to 30 mmHg. A correlation-based ultrasound speckle tracking algorithm was used to compute pressure-induced displacements within the scanned tissue cross-sections. Radial, tangential, and shear strains were calculated for the PPR, PPS, and ONH regions. In PPR, shear was significantly larger in magnitude than radial and tangential strains. Strain maps showed localized high shear and high tangential strains in PPR. In comparison to PPS and ONH, PPR had greater shear and a similar level of tangential strain. Surprisingly, PPR radial compression was minimal and significantly smaller than that in PPS. These results provide new insights into PPR deformation in response of IOP elevation, suggesting that shear rather than compression was likely the primary mode of IOP-induced mechanical insult in PPR. High shear, especially localized high shear, may contribute to the mechanical damage of this tissue in glaucoma.
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Affiliation(s)
- Sunny Kwok
- Department of Biomedical Engineering, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
| | - Manqi Pan
- Department of Biomedical Engineering, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
| | - Nicholas Hazen
- Biophysics Interdisciplinary Group, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
| | - Xueliang Pan
- Department of Biomedical Informatics, Ohio State University, 1800 Cannon Drive, Columbus, OH 43210
| | - Jun Liu
- Department of Biomedical Engineering, Ohio State University, 140 W 19th Ave, Columbus, OH 43210
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Waisberg E, Micieli JA. Neuro-Ophthalmological Optic Nerve Cupping: An Overview. Eye Brain 2021; 13:255-268. [PMID: 34934377 PMCID: PMC8684388 DOI: 10.2147/eb.s272343] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/02/2021] [Indexed: 11/23/2022] Open
Abstract
Optic nerve cupping or enlargement of the cup-to-disc ratio is widely recognized as a feature of glaucoma, however it may also occur in non-glaucomatous optic neuropathies. The most well-recognized non-glaucomatous optic neuropathies that cause cupping include compressive optic neuropathies, arteritic anterior ischemic optic neuropathies, hereditary optic neuropathies, and optic neuritis. Cupping is thought to consist of two main components: prelaminar and laminar thinning. The former is a shallow form of cupping and related to loss of retinal ganglion cells, whereas the latter involves damage to the lamina cribrosa and peripapillary scleral connective tissue. Differentiating glaucomatous and non-glaucomatous optic nerve cupping remains challenging even for experienced observers. Classically, the optic nerve in non-glaucomatous causes has pallor of the neuroretinal rim, but the optic nerve should not be examined in isolation. The patient’s medical history, history of presenting illness, visual function (visual acuity, color vision and visual field testing) and ocular examination also need to be considered. Ancillary testing such as optical coherence tomography of the retinal nerve fiber layer and ganglion cell layer-inner plexiform layer may also be helpful in localizing the disease. In this review, we review the non-glaucomatous causes of cupping and provide an approach to evaluating a patient that presents with an enlarged cup-to-disc ratio.
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Affiliation(s)
- Ethan Waisberg
- UCD School of Medicine, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Jonathan A Micieli
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.,Kensington Vision and Research Centre, Toronto, Ontario, Canada
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