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Xie M, Tang J, Zhang Y, Deng Y, Ma K, Xiang X, Tang L. Assessment of the Corneal Biomechanical Features of Sturge-Weber Syndrome Using Dynamic Ultrahigh-speed Scheimpflug Imaging. Cornea 2024:00003226-990000000-00650. [PMID: 39104013 DOI: 10.1097/ico.0000000000003617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 05/29/2024] [Indexed: 08/07/2024]
Abstract
PURPOSE To evaluate the corneal biomechanical characteristics of eyes with Sturge-Weber syndrome (SWS) secondary glaucoma (SSG) by analyzing corneal biomechanical parameters obtained using the Corneal Visualization Scheimpflug Technology instrument (Corvis ST). METHODS In patients with SWS, eyes affected by SSG were designated as the SSG group while the contralateral eyes were designated as the SWS contralateral group (SC group). Patients from the myopia clinic served as the control group. Dynamic corneal response parameters (DCRs) including the stress-strain index (SSI)-a critical material stiffness parameter that excludes interference from IOP and central corneal thickness (CCT)-were analyzed. RESULTS For CCT, no significant difference was observed between the SSG and SC groups. However, significant differences were found between the SSG and control groups and between the SC and control groups. Parameters such as HC Time, A1 Deformation Amp., A2 Deformation Amp., length of Whole Eye Movement (WEM), DA Ratio Max (2 mm), PachySlope, DA Ratio Max (1 mm), and ARTh showed significant differences between the SSG group and control group. In the SSG group, 4 of night eyes had an SSI of less than 0.85. CONCLUSIONS Some DCRs indicated a stiffer cornea in the SSG group, possibly due to a thicker cornea in this group. On analyzing SSI, it was found that corneal material properties change, becoming less stiff in some of the patients with SSG. In conclusion, our study provides a preliminary exploration of the biomechanical properties of SWS secondary glaucoma.
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Affiliation(s)
- Mengzhen Xie
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- West China School of Medicine, Sichuan University, Chengdu, Sichuan, China
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Jing Tang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Yao Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- West China School of Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Yingping Deng
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Ke Ma
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Xingye Xiang
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, China; and
- Georgia State University, Atlanta, GA
| | - Li Tang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
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Fujiwara K, Ueda E, Hata J, Nakano S, Hashimoto S, Nakamura S, Murakami Y, Kubota T, Yoshitomi T, Ninomiya T, Sonoda KH. Association between corneal hysteresis and glaucoma in a Japanese population: the Hisayama Study. Br J Ophthalmol 2024; 108:1204-1209. [PMID: 38471749 DOI: 10.1136/bjo-2023-323987] [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: 05/25/2023] [Accepted: 01/22/2024] [Indexed: 03/14/2024]
Abstract
AIMS To investigate the association between corneal hysteresis and the presence of glaucoma and its subtypes in a general Japanese population. METHODS We analysed the data of 2338 Japanese community-dwellers aged ≥40 years (1059 men, 1279 women) who underwent an eye examination in 2018 as part of the population-based, cross-sectional Hisayama Study. Participants were divided into quartile levels of corneal hysteresis, which had been measured with an ocular response analyzer. Glaucoma was defined based on the International Society of Geographical and Epidemiological Ophthalmology criteria. We conducted a logistic regression analysis to determine the ORs and their 95% CIs for the presence of outcomes according to the corneal hysteresis quartiles. RESULTS Glaucoma was diagnosed in 154 participants: primary open-angle glaucoma (POAG), n=115; primary angle-closure glaucoma, n=17; exfoliation glaucoma, n=21 and secondary glaucoma without exfoliation glaucoma, n=1. After adjustment for confounders, the OR for prevalent glaucoma was significantly increased in the participants in the first corneal-hysteresis quartile compared with those in the fourth quartile (OR: 1.80; 95% CI: 1.03 to 3.17). Regarding glaucoma subtypes, the first-quartile participants had significantly greater likelihoods of the presence of POAG (OR: 1.63; 95% CI: 1.02 to 2.61) and exfoliation glaucoma (OR: 6.49; 95% CI: 1.44 to 29.30) compared with those in the third and fourth quartiles after adjustment for potential confounders. CONCLUSIONS These results demonstrated a significant inverse association between corneal hysteresis and the likelihood of glaucoma, suggesting that the measurement of corneal hysteresis would provide useful information for elucidating the aetiology of glaucoma.
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Affiliation(s)
- Kohta Fujiwara
- Department of Epidemiology and Public Health, Kyushu University, Fukuoka, Japan
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Emi Ueda
- Department of Epidemiology and Public Health, Kyushu University, Fukuoka, Japan
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Jun Hata
- Department of Epidemiology and Public Health, Kyushu University, Fukuoka, Japan
- Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoko Nakano
- Department of Ophthalmology, Oita University Faculty of Medicine, Yufu-City, Oita, Japan
| | - Sawako Hashimoto
- Department of Epidemiology and Public Health, Kyushu University, Fukuoka, Japan
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shun Nakamura
- Department of Epidemiology and Public Health, Kyushu University, Fukuoka, Japan
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yusuke Murakami
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshiaki Kubota
- Department of Ophthalmology, Oita University Faculty of Medicine, Yufu-City, Oita, Japan
| | - Takeshi Yoshitomi
- Department of Orthoptics, Fukuoka International University of Health and Welfare, Fukuoka, Japan
| | - Toshiharu Ninomiya
- Department of Epidemiology and Public Health, Kyushu University, Fukuoka, Japan
- Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koh-Hei Sonoda
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Sripinun P, See LP, Nikonov S, Chavali VRM, Vrathasha V, He J, O'Brien JM, Xia J, Lu W, Mitchell CH. Piezo1 and Piezo2 channels in retinal ganglion cells and the impact of Piezo1 stimulation on light-dependent neural activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.599602. [PMID: 38979351 PMCID: PMC11230181 DOI: 10.1101/2024.06.25.599602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Piezo channels are associated with neuropathology in diseases like traumatic brain injury and glaucoma, but pathways linking tissue stretch to aberrant neural signaling remain unclear. The present study demonstrates that Piezo1 activation increases action potential frequency in response to light and the spontaneous dark signal from mouse retinal explants. Piezo1 stimulation was sufficient to increase cytoplasmic Ca 2+ in soma and neurites, while stretch increased spiking activity in current clamp recordings from of isolated retinal ganglion cells (RGCs). Axon-marker beta-tubulin III colocalized with both Piezo1 and Piezo2 protein in the mouse optic nerve head, while RGC nuclear marker BRN3A colocalized with Piezo channels in the soma. Piezo1 was also present on GFAP-positive regions in the optic nerve head and colocalized with glutamine synthetase in the nerve fiber layer, suggesting expression in optic nerve head astrocytes and Müller glia end feet, respectively. Human RGCs from induced pluripotent stem cells also expressed Piezo1 and Piezo2 in soma and axons, while staining patterns in rats resembled those in mice. mRNA message for Piezo1 was greatest in the RPE/choroid tissue, while Piezo2 levels were highest in the optic nerve, with both channels also expressed in the retina. Increased expression of Piezo1 and Piezo2 occurred both 1 and 10 days after a single stretch in vivo; this increase suggests a potential role in rising sensitivity to repeated nerve stretch. In summary, Piezo1 and Piezo2 were detected in the soma and axons of RGCs, and stimulation affected the light-dependent output of RGCs. The rise in RGCs excitability induced by Piezo stimulation may have parallels to the early disease progression in models of glaucoma and other retinal degenerations. Highlights Activation of Piezo1 excites retinal ganglion cells, paralleling the early neurodegenerative progression in glaucoma mouse models and retinal degeneration.Piezo1 and Piezo2 were expressed in axons and soma of retinal ganglion cells in mice, rats, and human iPSC-RGCs.Functional assays confirmed Piezo1 in soma and neurites of neurons. Sustained elevation of Piezo1 and Piezo2 occurred after a single transient stretch may enhance damage from repeated traumatic nerve injury. Abstract Figure
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Baptista PML, Ferreira AS, Silva NP, Figueiredo ARM, Sampaio IC, Reis RVF, Ambrósio R, Menéres PMAM, Beirão JNM, Menéres MJFS. Scheimpflug-Based Corneal Biomechanical Analysis As A Predictor of Glaucoma in Eyes With High Myopia. Clin Ophthalmol 2024; 18:545-563. [PMID: 38410632 PMCID: PMC10895980 DOI: 10.2147/opth.s426635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/04/2024] [Indexed: 02/28/2024] Open
Abstract
Purpose To address if corneal biomechanical behavior has a predictive value for the presence of glaucomatous optical neuropathy in eyes with high myopia. Patients and Methods This observational cross-sectional study included 209 eyes from 108 consecutive patients, divided into four groups: high myopia and primary open-angle glaucoma (POAG) - HMG, n = 53; high myopia without POAG - HMNG, n = 53; non-myopic with POAG - POAG, n = 50; non-myopic and non-POAG- NMNG, n = 53. Biomechanical assessment was made through a Scheimpflug-camera-based technology. Receiver operating characteristic curves were made for the discrimination between groups. Multivariable logistic regression models were performed to address the predictive value of corneal biomechanics for the presence of glaucoma. Results Areas Under the Receiver Operating Characteristic (AUROCs) above 0.6 were found in 6 parameters applied to discriminate between HMG and HMNG and six parameters to discriminate between POAG and NMNG. The biomechanical models with the highest power of prediction for the presence of glaucoma included 5 parameters with an AUROC of 0.947 for eyes with high myopia and 6 parameters with an AUROC of 0.857 for non-myopic eyes. In the final model, including all eyes, and adjusted for the presence of high myopia, the highest power of prediction for the presence of glaucoma was achieved including eight biomechanical parameters, with an AUROC of 0.917. Conclusion Corneal biomechanics demonstrated differences in eyes with glaucoma and mainly in myopic eyes. A biomechanical model based on multivariable logistic regression analysis and adjusted for high myopia was built, with an overall probability of 91.7% for the correct prediction of glaucomatous damage.
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Affiliation(s)
- Pedro M L Baptista
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - André S Ferreira
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Faculdade de Medicina da Universidade do Porto, Universidade do Porto, Porto, Portugal
| | - Nisa P Silva
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Ana R M Figueiredo
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Isabel C Sampaio
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Rita V F Reis
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Renato Ambrósio
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, RJ, Brazil
- Department of Cornea and Refractive Surgery, Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- Department of Ophthalmology, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil
| | - Pedro M A M Menéres
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - João N M Beirão
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Maria J F S Menéres
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Luo J, Zhang Y, Ai S, Shi G, Han X, Wang Y, Zhao Y, Yang H, Li Y, He X. Two-dimensional elastic distribution imaging of the sclera using acoustic radiation force optical coherence elastography. JOURNAL OF BIOPHOTONICS 2024; 17:e202300368. [PMID: 38010344 DOI: 10.1002/jbio.202300368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/23/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
The scleral elasticity is closely related with many ocular diseases, but the relevant research is still insufficient. Here, we utilized optical coherence elastography to carefully study biomechanical properties of the sclera at different positions and under different intraocular pressures. Meanwhile, elastic wave velocity and Young's modulus of each position were obtained using a phase velocity algorithm. Accordingly, the two-dimensional elasticity distribution image was achieved by mapping the Young's modulus values to the corresponding structure based on the relationship between the position and its Young's modulus. Therefore, elastic information in regions-of-interest can be read and compared directly from the scleral structure, indicating that our method may be a very useful tool to evaluate the elasticity of sclera and provide intuitive and reliable proof for diagnosis and research.
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Affiliation(s)
- Jiahui Luo
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Yubao Zhang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Sizhu Ai
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Gang Shi
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Xiao Han
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Yidi Wang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Yanzhi Zhao
- Eye Center, Second Affiliated Hospital of Nanchang University, Nanchang, PR China
| | - Hongwei Yang
- Eye Center, Second Affiliated Hospital of Nanchang University, Nanchang, PR China
| | - Yingjie Li
- Department of Ophthalmology, Nanchang First Hospital, Nanchang, PR China
| | - Xingdao He
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
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Sala L, Prud’homme C, Guidoboni G, Szopos M, Harris A. The ocular mathematical virtual simulator: A validated multiscale model for hemodynamics and biomechanics in the human eye. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3791. [PMID: 37991116 PMCID: PMC10922164 DOI: 10.1002/cnm.3791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 10/22/2023] [Indexed: 11/23/2023]
Abstract
We present our continuous efforts from a modeling and numerical viewpoint to develop a powerful and flexible mathematical and computational framework called Ocular Mathematical Virtual Simulator (OMVS). The OMVS aims to solve problems arising in biomechanics and hemodynamics within the human eye. We discuss our contribution towards improving the reliability and reproducibility of computational studies by performing a thorough validation of the numerical predictions against experimental data. The OMVS proved capable of simulating complex multiphysics and multiscale scenarios motivated by the study of glaucoma. Furthermore, its modular design allows the continuous integration of new models and methods as the research moves forward, and supports the utilization of the OMVS as a promising non-invasive clinical investigation tool for personalized research in ophthalmology.
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Affiliation(s)
- Lorenzo Sala
- Université Paris-Saclay, INRAE, MaIAGE, 78350, Jouy-en-Josas, France
| | | | | | - Marcela Szopos
- Université Paris Cité, CNRS, MAP5, F-75006 Paris, France
| | - Alon Harris
- Icahn School of Medicine at Mount Sinai, New York (NY), 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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Lee PY, Fryc G, Gnalian J, Wang B, Hua Y, Waxman S, Zhong F, Yang B, Sigal IA. Direct measurements of collagen fiber recruitment in the posterior pole of the eye. Acta Biomater 2024; 173:135-147. [PMID: 37967694 PMCID: PMC10843755 DOI: 10.1016/j.actbio.2023.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/17/2023]
Abstract
Collagen is the main load-bearing component of the peripapillary sclera (PPS) and lamina cribrosa (LC) in the eye. Whilst it has been shown that uncrimping and recruitment of the PPS and LC collagen fibers underlies the macro-scale nonlinear stiffening of both tissues with increased intraocular pressure (IOP), the uncrimping and recruitment as a function of local stretch have not been directly measured. This knowledge is crucial to understanding their functions in bearing loads and maintaining tissue integrity. In this project we measured local stretch-induced collagen fiber bundle uncrimping and recruitment curves of the PPS and LC. Thin coronal samples of PPS and LC of sheep eyes were mounted and stretched biaxially quasi-statically using a custom system. At each step, we imaged the PPS and LC with instant polarized light microscopy and quantified pixel-level (1.5 μm/pixel) collagen fiber orientations. We used digital image correlation to measure the local stretch and quantified collagen crimp by the circular standard deviation of fiber orientations, or waviness. Local stretch-recruitment curves of PPS and LC approximated sigmoid functions. PPS recruited more fibers than the LC at the low levels of stretch. At 10% stretch the curves crossed with 75% bundles recruited. The PPS had higher uncrimping rate and waviness remaining after recruitment than the LC: 0.9º vs. 0.6º and 3.1º vs. 2.7º. Altogether our findings support describing fiber recruitment of both PPS and LC with sigmoid curves, with the PPS recruiting faster and at lower stretch than the LC, consistent with a stiffer tissue. STATEMENT OF SIGNIFICANCE: Peripapillary sclera (PPS) and lamina cribrosa (LC) collagen recruitment behaviors are central to the nonlinear mechanical behavior of the posterior pole of the eye. How PPS and LC collagen fibers recruit under stretch is crucial to develop constitutive models of the tissues but remains unclear. We used image-based stretch testing to characterize PPS and LC collagen fiber bundle recruitment under local stretch. We found that fiber-level stretch-recruitment curves of PPS and LC approximated sigmoid functions. PPS recruited more fibers at a low stretch, but at 10% bundle stretch the two curves crossed with 75% bundles recruited. We also found that PPS and LC fibers had different uncrimping rates and non-zero waviness's when recruited.
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Affiliation(s)
- Po-Yi Lee
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gosia Fryc
- Department of Chemistry, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - John Gnalian
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bingrui Wang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yi Hua
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Biomedical Engineering, University of Mississippi, University, MS, USA; Department of Mechanical Engineering, University of Mississippi, University, MS, USA
| | - Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Fuqiang Zhong
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bin Yang
- Department of Engineering, Rangos School of Health Sciences, Duquesne University, Pittsburgh, PA, USA
| | - Ian A Sigal
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Callejas A, Faris I, Torres J, Rus G. Nonlinear fourth-order elastic characterization of the cornea using torsional wave elastography. Phys Eng Sci Med 2023; 46:1489-1501. [PMID: 37642939 DOI: 10.1007/s13246-023-01314-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 07/26/2023] [Indexed: 08/31/2023]
Abstract
Measuring the mechanical nonlinear properties of the cornea remains challenging due to the lack of consensus in the methodology and in the models that effectively predict its behaviour. This study proposed developing a procedure to reconstruct nonlinear fourth-order elastic properties of the cornea based on a mathematical model derived from the theory of Hamilton et al. and using the torsional wave elastography (TWE) technique. In order to validate its diagnostic capability of simulated pathological conditions, two different groups were studied, non-treated cornea samples (n=7), and ammonium hydroxide ([Formula: see text]) treated samples (n=7). All the samples were measured in-plane by a torsional wave device by increasing IOP from 5 to 25 mmHg with 5 mmHg steps. The results show a nonlinear variation of the shear wave speed with the IOP, with higher values for higher IOPs. Moreover, the shear wave speed values of the control group were higher than those of the treated group. The study also revealed significant differences between the control and treated groups for the Lamé parameter [Formula: see text] (25.9-6.52 kPa), third-order elastic constant A (215.09-44.85 kPa), and fourth-order elastic constant D (523.5-129.63 kPa), with p-values of 0.010, 0.024, and 0.032, respectively. These findings demonstrate that the proposed procedure can distinguish between healthy and damaged corneas, making it a promising technique for detecting diseases associated with IOP alteration, such as corneal burns, glaucoma, or ocular hypertension.
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Affiliation(s)
- Antonio Callejas
- Ultrasonics Lab (TEP-959), Department of Structural Mechanics, University of Granada, Granada, 18071, Spain.
- TEC-12 group, Instituto de Investigación Biosanitaria, ibs.Granada, 18001, Spain.
| | - Inas Faris
- Ultrasonics Lab (TEP-959), Department of Structural Mechanics, University of Granada, Granada, 18071, Spain
- TEC-12 group, Instituto de Investigación Biosanitaria, ibs.Granada, 18001, Spain
| | - Jorge Torres
- Ultrasonics Lab (TEP-959), Department of Structural Mechanics, University of Granada, Granada, 18071, Spain
- TEC-12 group, Instituto de Investigación Biosanitaria, ibs.Granada, 18001, Spain
| | - Guillermo Rus
- Ultrasonics Lab (TEP-959), Department of Structural Mechanics, University of Granada, Granada, 18071, Spain
- TEC-12 group, Instituto de Investigación Biosanitaria, ibs.Granada, 18001, Spain
- Excellence Research Unit "ModelingNature" (MNat), Universidad de Granada, Granada, 18001, Spain
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10
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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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Bou Ghanem GO, Koktysh D, Baratta RO, Del Buono BJ, Schlumpf E, Wareham LK, Calkins DJ. Collagen Mimetic Peptides Promote Repair of MMP-1-Damaged Collagen in the Rodent Sclera and Optic Nerve Head. Int J Mol Sci 2023; 24:17031. [PMID: 38069354 PMCID: PMC10707085 DOI: 10.3390/ijms242317031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/20/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
The structural and biomechanical properties of collagen-rich ocular tissues, such as the sclera, are integral to ocular function. The degradation of collagen in such tissues is associated with debilitating ophthalmic diseases such as glaucoma and myopia, which often lead to visual impairment. Collagen mimetic peptides (CMPs) have emerged as an effective treatment to repair damaged collagen in tissues of the optic projection, such as the retina and optic nerve. In this study, we used atomic force microscopy (AFM) to assess the potential of CMPs in restoring tissue stiffness in the optic nerve head (ONH), including the peripapillary sclera (PPS) and the glial lamina. Using rat ONH tissue sections, we induced collagen damage with MMP-1, followed by treatment with CMP-3 or vehicle. MMP-1 significantly reduced the Young's modulus of both the PPS and the glial lamina, indicating tissue softening. Subsequent CMP-3 treatment partially restored tissue stiffness in both the PPS and the glial lamina. Immunohistochemical analyses revealed reduced collagen fragmentation after MMP-1 digestion in CMP-3-treated tissues compared to vehicle controls. In summary, these results demonstrate the potential of CMPs to restore collagen stiffness and structure in ONH tissues following enzymatic damage. CMPs may offer a promising therapeutic avenue for preserving vision in ocular disorders involving collagen remodeling and degradation.
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Affiliation(s)
- Ghazi O. Bou Ghanem
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - Dmitry Koktysh
- Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN 37212, USA
| | | | | | - Eric Schlumpf
- Stuart Therapeutics, Inc., Stuart, FL 34994, USA; (R.O.B.); (E.S.)
| | - Lauren K. Wareham
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
| | - David J. Calkins
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
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12
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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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13
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Brown DM, Yu J, Kumar P, Paulus QM, Kowalski MA, Patel JM, Kane MA, Ethier CR, Pardue MT. Exogenous All-Trans Retinoic Acid Induces Myopia and Alters Scleral Biomechanics in Mice. Invest Ophthalmol Vis Sci 2023; 64:22. [PMID: 37219510 PMCID: PMC10210516 DOI: 10.1167/iovs.64.5.22] [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: 10/21/2022] [Accepted: 04/21/2023] [Indexed: 05/24/2023] Open
Abstract
Purpose Ocular all-trans retinoic acid (atRA) levels are influenced by visual cues, and exogenous atRA has been shown to increase eye size in chickens and guinea pigs. However, it is not clear whether atRA induces myopic axial elongation via scleral changes. Here, we test the hypothesis that exogenous atRA will induce myopia and alter scleral biomechanics in the mouse. Methods Male C57BL/6J mice were trained to voluntarily ingest atRA + vehicle (1% atRA in sugar, 25 mg/kg) (RA: n = 16 animals) or vehicle only (Ctrl: n = 14 animals). Refractive error (RE) and ocular biometry were measured at baseline and after 1 and 2 weeks of daily atRA treatment. Eyes were used in ex vivo assays to measure scleral biomechanics (unconfined compression: n = 18), total scleral sulfated glycosaminoglycan (sGAG) content (dimethylmethylene blue: n = 23), and specific sGAGs (immunohistochemistry: n = 18). Results Exogenous atRA caused myopic RE and larger vitreous chamber depth (VCD) to develop by 1 week (RE: -3.7 ± 2.2 diopters [D], P < 0.001; VCD: +20.7 ± 15.1 µm, P < 0.001), becoming more severe by 2 weeks (RE: -5.7 ± 2.2 D, P < 0.001; VCD: +32.3 ± 25.8 µm, P < 0.001). The anterior eye biometry was unaffected. While scleral sGAG content was not measurably affected, scleral biomechanics were significantly altered (tensile stiffness: -30% ± 19.5%, P < 0.001; permeability: +60% ± 95.3%, P < 0.001). Conclusions In mice, atRA treatment results in an axial myopia phenotype. Eyes developed myopic RE and larger VCD without the anterior eye being affected. The decrease in stiffness and increase in permeability of the sclera are consistent with the form-deprivation myopia phenotype.
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Affiliation(s)
- Dillon M. Brown
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Healthcare System, Atlanta, Georgia, United States
| | - Jianshi Yu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, United States
| | - Praveen Kumar
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, United States
| | - Quinn M. Paulus
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Healthcare System, Atlanta, Georgia, United States
| | - Michael A. Kowalski
- Department of Orthopaedics, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Jay M. Patel
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Healthcare System, Atlanta, Georgia, United States
- Department of Orthopaedics, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, United States
| | - C. Ross Ethier
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Machelle T. Pardue
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Healthcare System, Atlanta, Georgia, United States
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, United States
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14
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Sit AJ, Chen TC, Takusagawa HL, Rosdahl JA, Hoguet A, Chopra V, Richter GM, Ou Y, Kim SJ, WuDunn D. Corneal Hysteresis for the Diagnosis of Glaucoma and Assessment of Progression Risk: A Report by the American Academy of Ophthalmology. Ophthalmology 2023; 130:433-442. [PMID: 36529572 DOI: 10.1016/j.ophtha.2022.11.009] [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: 09/27/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 12/23/2022] Open
Abstract
PURPOSE To review the current published literature on the utility of corneal hysteresis (CH) to assist the clinician in the diagnosis of glaucoma or in the assessment of risk for disease progression in existing glaucoma patients. METHODS Searches of the peer-reviewed literature in the PubMed database were performed through July 2022. The abstracts of 423 identified articles were examined to exclude reviews and non-English articles. After inclusion and exclusion criteria were applied, 19 articles were selected, and the panel methodologist rated them for level of evidence. Eight articles were rated level I, and 5 articles were rated level II. The 6 articles rated level III were excluded. RESULTS Corneal hysteresis is lower in patients with primary open-angle glaucoma, primary angle-closure glaucoma, pseudoexfoliative glaucoma, and pseudoexfoliation syndrome compared with normal subjects. Interpretation of low CH in patients with high intraocular pressure (IOP) or on topical hypotensive medications is complicated by the influence of these parameters on CH measurements. However, CH is also lower in treatment-naïve, normal-tension glaucoma patients compared with normal subjects who have a similar IOP. In addition, lower CH is associated with an increased risk of progression of glaucoma based on visual fields or structural markers in open-angle glaucoma patients, including those with apparently well-controlled IOP. CONCLUSIONS Corneal hysteresis is lower in glaucoma patients compared with normal subjects, and lower CH is associated with an increased risk of disease progression. However, a causal relationship remains to be demonstrated. Nevertheless, measurement of CH complements current structural and functional assessments in determining disease risk in glaucoma suspects and patients. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Arthur J Sit
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.
| | - Teresa C Chen
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye & Ear, Glaucoma Service, Boston, Massachusetts
| | - Hana L Takusagawa
- VA Eugene Healthcare Center, Eugene, Oregon; Casey Eye Institute, Oregon Health & Sciences University, Portland, Oregon
| | - Jullia A Rosdahl
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina
| | - Ambika Hoguet
- Ophthalmic Consultants of Boston, Boston, Massachusetts
| | | | - Grace M Richter
- Department of Ophthalmology, Southern California Permanente Medical Group, Kaiser Permanente Los Angeles Medical Center, Los Angeles, California; USC Roski Eye Institute Keck Medicine of University of Southern California Los Angeles, Los Angeles, California
| | - Yvonne Ou
- Department of Ophthalmology, UCSF Medical Center, San Francisco, California
| | - Stephen J Kim
- Department of Ophthalmology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Darrell WuDunn
- University of Florida College of Medicine, Jacksonville, Department of Ophthalmology, Jacksonville, Florida
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15
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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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16
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Czerpak CA, Kashaf MS, Zimmerman BK, Quigley HA, Nguyen TD. The Strain Response to Intraocular Pressure Decrease in the Lamina Cribrosa of Patients with Glaucoma. Ophthalmol Glaucoma 2023; 6:11-22. [PMID: 35863747 PMCID: PMC9849479 DOI: 10.1016/j.ogla.2022.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To measure biomechanical strains in the lamina cribrosa (LC) of living human eyes with intraocular pressure (IOP) lowering. DESIGN Cohort study. PARTICIPANTS Patients with glaucoma underwent imaging before and after laser suturelysis after trabeculectomy surgery (29 image pairs; 26 persons). INTERVENTION Noninvasive imaging of the eye. MAIN OUTCOME MEASURES Strains in optic nerve head tissue and changes in depths of the anterior border of the LC. RESULTS Intraocular pressure decreases caused the LC to expand in thickness in the anterior-posterior strain (Ezz = 0.94 ± 1.2%; P = 0.00020) and contract in radius in the radial strain (Err = - 0.19 ± 0.33%; P = 0.0043). The mean LC depth did not significantly change with IOP lowering (1.33 ± 6.26 μm; P = 0.26). A larger IOP decrease produced a larger, more tensile Ezz (P < 0.0001), greater maximum principal strain (Emax; P < 0.0001), and greater maximum shear strain (Γmax; P < 0.0001). The average LC depth change was associated with the Γmax and radial-circumferential shear strain (Erθ; P < 0.02) but was not significantly related to tensile or compressive strains. An analysis by clock hour showed that in temporal clock hours 3 to 6, a more anterior LC movement was associated with a more positive Emax, and in clock hours 3, 5, and 6, it was associated with a more positive Γmax. At 10 o'clock, a more posterior LC movement was related to a more positive Emax (P < 0.004). Greater compliance (strain/ΔIOP) of Emax (P = 0.044), Γmax (P = 0.052), and Erθ (P = 0.018) was associated with a thinner retinal nerve fiber layer. Greater compliance of Emax (P = 0.041), Γmax (P = 0.021), Erθ (P = 0.024), and in-plane shear strain (Erz; P = 0.0069) was associated with more negative mean deviations. Greater compliance of Γmax (P = 0.055), Erθ (P = 0.040), and Erz (P = 0.015) was associated with lower visual field indices. CONCLUSIONS With IOP lowering, the LC moves either into or out of the eye but, on average, expands in thickness and contracts in radius. Shear strains are nearly as substantial as in-plane strains. Biomechanical strains are more compliant in eyes with greater glaucoma damage. This work was registered at ClinicalTrials.gov as NCT03267849.
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Affiliation(s)
- Cameron A Czerpak
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland.
| | - Michael Saheb Kashaf
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland
| | - Brandon K Zimmerman
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland
| | - Harry A Quigley
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland
| | - Thao D Nguyen
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland; Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland
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17
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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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18
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Qiu C, Wang C, Sun X, Xu J, Wu J, Zhang R, Li G, Xue K, Zhang X, Qian S. CXC‐ receptor 2 promotes extracellular matrix production and attenuates migration in peripapillary human scleral fibroblasts under mechanical strain. J Cell Mol Med 2022; 26:5858-5871. [DOI: 10.1111/jcmm.17609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/15/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Chen Qiu
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- NHC Key Laboratory of Myopia Fudan University Shanghai China
- Laboratory of Myopia Chinese Academy of Medical Sciences Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
| | - Chuandong Wang
- Department of Orthopedic Surgery Xin Hua Hospital Affiliated to Shanghai Jiaotong University School of Medicine Shanghai China
| | - Xinghuai Sun
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- NHC Key Laboratory of Myopia Fudan University Shanghai China
- Laboratory of Myopia Chinese Academy of Medical Sciences Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science Fudan University Shanghai China
| | - Jianjiang Xu
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- NHC Key Laboratory of Myopia Fudan University Shanghai China
- Laboratory of Myopia Chinese Academy of Medical Sciences Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
| | - Jihong Wu
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- NHC Key Laboratory of Myopia Fudan University Shanghai China
- Laboratory of Myopia Chinese Academy of Medical Sciences Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
| | - Rong Zhang
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- NHC Key Laboratory of Myopia Fudan University Shanghai China
- Laboratory of Myopia Chinese Academy of Medical Sciences Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
| | - Gang Li
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- NHC Key Laboratory of Myopia Fudan University Shanghai China
- Laboratory of Myopia Chinese Academy of Medical Sciences Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
| | - Kang Xue
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
| | - Xiaoling Zhang
- Department of Orthopedic Surgery Xin Hua Hospital Affiliated to Shanghai Jiaotong University School of Medicine Shanghai China
| | - Shaohong Qian
- Department of Ophthalmology and Vision Science, Eye and Ear, Nose, Throat Hospital, Shanghai Medical College Fudan University Shanghai China
- NHC Key Laboratory of Myopia Fudan University Shanghai China
- Laboratory of Myopia Chinese Academy of Medical Sciences Shanghai China
- Shanghai Key Laboratory of Visual Impairment and Restoration Fudan University Shanghai China
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19
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Guan C, Pease ME, Quillen S, Ling YTT, Li X, Kimball E, Johnson TV, Nguyen TD, Quigley HA. Quantitative Microstructural Analysis of Cellular and Tissue Remodeling in Human Glaucoma Optic Nerve Head. Invest Ophthalmol Vis Sci 2022; 63:18. [PMID: 36269186 PMCID: PMC9617510 DOI: 10.1167/iovs.63.11.18] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/23/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose To measure quantitatively changes in lamina cribrosa (LC) cell and connective tissue structure in human glaucoma eyes. Methods We studied 27 glaucoma and 19 age-matched non-glaucoma postmortem eyes. In 25 eyes, LC cross-sections were examined by confocal and multiphoton microscopy to quantify structures identified by anti-glial fibrillary acidic protein (GFAP), phalloidin-labeled F-actin, nuclear 4',6-diamidino-2-phenylindole (DAPI), and by second harmonic generation imaging of LC beams. Additional light and transmission electron microscopy were performed in 21 eyes to confirm features of LC remodeling, including immunolabeling by anti-SOX9 and anti-collagen IV. All glaucoma eyes had detailed clinical histories of open-angle glaucoma status, and degree of axon loss was quantified in retrolaminar optic nerve cross-sections. Results Within LC pores, the proportionate area of both GFAP and F-actin processes was significantly lower in glaucoma eyes than in controls (P = 0.01). Nuclei were rounder (lower median aspect ratio) in glaucoma specimens (P = 0.02). In models assessing degree of glaucoma damage, F-actin process width was significantly wider in glaucoma eyes with more damage (P = 0.024), average LC beam width decreased with worse glaucoma damage (P = 0.042), and nuclear count per square millimeter rose with worse damage (P = 0.019). The greater cell count in LC pores represented 92.3% astrocytes by SOX9 labeling. The results are consistent with replacement of axons in LC pores by basement membrane labeled by anti-collagen IV and in-migrating astrocytes. Conclusions Alteration in LC structure in glaucoma involves migration of astrocytes into axonal bundles, change in astrocyte orientation and processes, production of basement membrane material, and thinning of connective tissue beams.
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Affiliation(s)
- Carolyn Guan
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Mary Ellen Pease
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Sarah Quillen
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Yik Tung Tracy Ling
- Departments of Mechanical Engineering and Materials Science & Engineering, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Ximin Li
- Department of Biostatistics, The Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Elizabeth Kimball
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Thomas V. Johnson
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Thao D. Nguyen
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States
- Departments of Mechanical Engineering and Materials Science & Engineering, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Harry A. Quigley
- Wilmer Ophthalmological Institute, School of Medicine, The Johns Hopkins University, Baltimore, Maryland, United States
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20
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Markert JE, Turner DC, Jasien JV, Nyankerh CNA, Samuels BC, Downs JC. Ocular Pulse Amplitude Correlates With Ocular Rigidity at Native IOP Despite the Variability in Intraocular Pulse Volume With Each Heartbeat. Transl Vis Sci Technol 2022; 11:6. [PMID: 36074454 PMCID: PMC9469039 DOI: 10.1167/tvst.11.9.6] [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] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to assess ocular coat mechanical behavior using controlled ocular microvolumetric injections (MVI) of 15 µL of balanced salt solution (BSS) infused over 1 second into the anterior chamber (AC) via a syringe pump. Methods Intraocular pressure (IOP) was continuously recorded at 200 Hz with a validated implantable IOP telemetry system in 7 eyes of 7 male rhesus macaques (nonhuman primates [NHPs]) during 5 MVIs in a series at native (3 trials), 15 and 20 mm Hg baseline IOPs, repeated in 2 to 5 sessions at least 2 weeks apart. Ocular rigidity coefficients (K) and ocular pulse volume (PV) were calculated for each trial. Data were averaged across sessions within eyes; PV was analyzed with a three-level nested ANOVA, and parameter relationships were analyzed with Pearson Correlation and linear regression. Results After MVI at native baseline IOP of 10.4 ± 1.6 mm Hg, IOP increased by 9.1 ± 2.8 mm Hg (∆IOP) at a 9.6 ± 2.7 mm Hg/s slope, ocular pulse amplitude (OPA) was 0.70 ± 0.13 mm Hg on average; the average K was 0.042 ± 0.010 µL-1 and average PV was 1.16 ± 0.43 µL. PV varied significantly between trials, days, and eyes (P ≤ 0.05). OPA was significantly correlated with K at native IOP: Pearson coefficients ranged from 0.71 to 0.83 (P ≤ 0.05) and R2 ranged from 0.50 to 0.69 (P ≤ 0.05) during the first trial. Conclusions The MVI-driven ∆IOP and slope can be used to assess ocular coat mechanical behavior and measure ocular rigidity. Translational Relevance Importantly, OPA at native IOP is correlated with ocular rigidity despite the significant variability in PV between heartbeats.
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Affiliation(s)
- John E Markert
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel C Turner
- Vision Science Graduate Program, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jessica V Jasien
- Vision Science Graduate Program, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Cyril N A Nyankerh
- Vision Science Graduate Program, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Brian C Samuels
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - J Crawford Downs
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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21
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Zhang J, Murgoitio-Esandi J, Qian X, Li R, Gong C, Nankali A, Hao L, Xu BY, Kirk Shung K, Oberai A, Zhou Q. High-Frequency Ultrasound Elastography to Assess the Nonlinear Elastic Properties of the Cornea and Ciliary Body. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2621-2629. [PMID: 35820015 PMCID: PMC9547080 DOI: 10.1109/tuffc.2022.3190400] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Mechanical properties of the anterior anatomical structures of the eye, such as the cornea and ciliary body, play a key role in the ocular function and homeostasis. However, measuring the biomechanical properties of the anterior ocular structures, especially deeper structures, such as the ciliary body, remains a challenge due to the lack of high-resolution imaging tools. Herein, we implement a mechanical shaker-based high-frequency ultrasound elastography technique that can track the induced elastic wave propagation to assess the linear and nonlinear elastic properties of anterior ocular structures. The findings of this study advance our understanding of the role of anterior ocular structures in the pathogenesis of different ocular disorders, such as glaucoma.
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22
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Elevated IOP Alters the Material Properties of Sclera and Lamina Cribrosa in Monkeys. DISEASE MARKERS 2022; 2022:5038847. [PMID: 36051361 PMCID: PMC9427265 DOI: 10.1155/2022/5038847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/02/2022] [Accepted: 07/25/2022] [Indexed: 12/02/2022]
Abstract
Objective Elevated intraocular pressure (IOP) has significant impacts on different stages in the progression of chronic glaucoma. In this study, we investigated changes in the material properties of sclera and lamina cribrosa (LC) in a nonhuman primate model with elevated IOP. Methods Normal adult Tibetan macaques were selected for the construction of elevated IOP model. After 40 days of stable maintenance on the ocular hypertension, the binocular eyeballs were obtained for the measurement of macroscopic parameters of the eyeballs. Posterior scleral tissue strips were obtained in circumferential and axial directions, and thickness was measured, respectively. Biomechanical parameters were obtained with stress relaxation, creep, and tensile test. The nanoindentation test was performed on the LC and scleral tissue around optic nerve head (ONH) to obtain compressive modulus. Results In the presence of elevated IOP, variations of the axial diameter of the eyeball were greater than those of the transverse diameter, and the mean scleral thickness around ONH was smaller in the experimental group than control group. The elastic modulus and stress relaxation modulus of sclera were larger, and the creep rate was lower in the experimental group than control group. In the control group, the elastic modulus and stress relaxation modulus of the circumferential sclera were larger in the axial direction, and creep rate was smaller. In the experimental group, there was no significant difference in biomechanical characteristics between the two directions. Compared to the control group, the compression modulus of the LC was smaller, and the compression modulus of sclera around ONH was larger in the experimental group. Conclusion Elevated IOP alters the viscoelasticity and anisotropy of sclera and LC. These may contribute to reduction of the organizational resistance to external forces and decline in the ability of self-recovery.
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23
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Chu Z, Ren Q, Chen M, Cheng L, Cheng H, Cui W, Bi W, Wu J. The relationship between axial length/corneal radius of curvature ratio and stress–strain index in myopic eyeballs: Using Corvis ST tonometry. Front Bioeng Biotechnol 2022; 10:939129. [PMID: 36046672 PMCID: PMC9420864 DOI: 10.3389/fbioe.2022.939129] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 07/13/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: This study aimed to investigate the correlation of axial length/corneal radius of curvature ratio with stress–strain index (SSI).Methods: Retrospective analysis was conducted to compare the right eyes of those with high myopia (HM, n = 132; age and 10–48 years) with those without high myopia (NHM, n = 135; age and 7–48 years), where the baseline axial length, corneal radius of curvature ratio, and central corneal thickness were analyzed; the differences in two groups were compared; and the relationship of axial length and axial length/corneal radius of curvature ratio with SSI were explored.Results: Compared with AL < 26mm, SSI significantly decreased when AL ≥ 26 mm (p = 0.001), while there was no correlation with AL in the NHM group (r = -0.14, p = 0.12) or HM group (r = -0.09, p = 0.32). AL/CR was significantly associated with SSI in both the NHM (r = -0.4, p < 0.001) and HM (r = -0.18, p = 0.04) groups. In the NHM group, AL/CR was significantly associated with SSI (unstandardized beta = -0.514, se = 0.109, p < 0.001) with the adjustment of age and gender. Additionally, a significant association of SSI with AL/CR was also found after adjusting for age and gender (unstandardized beta = -0.258, se = 0.096, and p = 0.0082) in the HM group.Conclusion: SSI showed a significant negative correlation with AL/CR in patients without high myopia and in patients with high myopia. However, SSI exhibited no decrease with the worsening of myopia, but it gradually remained stable at a low level. The findings of this study validate, to some extent, the possibility of analyzing the dynamic changes in ocular wall stiffness during the development of myopia by measuring in vivo corneal biomechanical parameters.
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Affiliation(s)
- Zhe Chu
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, China
| | - Qi Ren
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, China
| | - Meizhen Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University Guangzhou, Guangzhou, China
| | - Lu Cheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University Guangzhou, Guangzhou, China
| | - Hao Cheng
- Department of Ophthalmology, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Wei Cui
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, China
| | - Wenjiao Bi
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, China
| | - Jie Wu
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, School of Ophthalmology, Shandong First Medical University, Qingdao, China
- *Correspondence: Jie Wu,
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24
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Song HH, Thoreson WB, Dong P, Shokrollahi Y, Gu L, Suh DW. Exploring the Vitreoretinal Interface: a Key Instigator of Unique Retinal Hemorrhage Patterns in Pediatric Head Trauma. KOREAN JOURNAL OF OPHTHALMOLOGY 2022; 36:253-263. [PMID: 35527527 PMCID: PMC9194735 DOI: 10.3341/kjo.2021.0133] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 02/18/2022] [Indexed: 11/25/2022] Open
Abstract
Purpose Various types of trauma can cause retinal hemorrhages in children, including accidental and nonaccidental head trauma. We used animal eyes and a finite element model of the eye to examine stress patterns produced during purely linear and angular accelerations, along with stresses attained during simulated repetitive shaking of an infant. Methods Using sheep and primate eyes, sclerotomy windows were created by removing the sclera, choroid, and retinal pigment epithelium to expose the retina. A nanofiber square was glued to a 5 mm2 area of retina. The square was pulled and separated from vitreous while force was measured. A finite element model of the pediatric eye was used to computationally measure tension stresses during shaking. Results In both sheep and primate eyes, tension stress required for separation of retina from vitreous range from 1 to 5 kPa. Tension stress generated at the vitreoretinal interface predicted by the computer simulation ranged from 3 to 16 kPa during a cycle of shaking. Linear acceleration generated lower tension stress than angular acceleration. Angular acceleration generated maximal tension stress along the retinal vasculature. Linear acceleration produced more diffuse force distribution centered at the poster pole. Conclusions The finite element model predicted that tension stress attained at the retina during forcible shaking of an eye can exceed the minimum threshold needed to produce vitreoretinal separation as measured in animal eyes. Furthermore, the results show that movements that involve significant angular acceleration produce strong stresses localized along the vasculature, whereas linear acceleration produces weaker, more diffuse stress centered towards the posterior pole of the eye.
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Affiliation(s)
- Helen H Song
- University of Nebraska Medical Center, Truhlsen Eye Institute, Omaha, NE
| | - Wallace B Thoreson
- University of Nebraska Medical Center, Truhlsen Eye Institute, Omaha, NE
| | - Pengfei Dong
- Florida Institute of Technology, Department of Biomedical & Chemical Engineering, Melbourne, FL
| | - Yasin Shokrollahi
- Florida Institute of Technology, Department of Biomedical & Chemical Engineering, Melbourne, FL
| | - Linxia Gu
- Florida Institute of Technology, Department of Biomedical & Chemical Engineering, Melbourne, FL
| | - Donny W Suh
- University of Nebraska Medical Center, Truhlsen Eye Institute, Omaha, NE.,Children's Hospital and Medical Center, Omaha, NE
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25
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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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26
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Wang Y, Cao H. Corneal and Scleral Biomechanics in Ophthalmic Diseases: An Updated Review. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2022. [DOI: 10.1016/j.medntd.2022.100140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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27
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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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28
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Karimi A, Rahmati SM, Razaghi R, Girkin CA, Crawford Downs J. Finite element modeling of the complex anisotropic mechanical behavior of the human sclera and pia mater. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 215:106618. [PMID: 35026624 PMCID: PMC8847341 DOI: 10.1016/j.cmpb.2022.106618] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/31/2021] [Accepted: 01/01/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Accurate finite element (FE) simulation of the optic nerve head (ONH) depends on accurate mechanical properties of the load-bearing tissues. The peripapillary sclera in the ONH exhibits a depth-dependent, anisotropic, heterogeneous collagen fiber distribution. This study proposes a novel cable-in-solid modeling approach that mimics heterogeneous anisotropic collagen fiber distribution, validates the approach against published experimental biaxial tensile tests of scleral patches, and demonstrates its effectiveness in a complex model of the posterior human eye and ONH. METHODS A computational pipeline was developed that defines control points in the sclera and pia mater, distributes the depth-dependent circumferential, radial, and isotropic cable elements in the sclera and pia in a pattern that mimics collagen fiber orientation, and couples the cable elements and solid matrix using a mesh-free penalty-based cable-in-solid algorithm. A parameter study was performed on a model of a human scleral patch subjected to biaxial deformation, and computational results were matched to published experimental data. The new approach was incorporated into a previously published eye-specific model to test the method; results were then interpreted in relation to the collagen fibers' (cable elements) role in the resultant ONH deformations, stresses, and strains. RESULTS Results show that the cable-in-solid approach can mimic the full range of scleral mechanical behavior measured experimentally. Disregarding the collagen fibers/cable elements in the posterior eye model resulted in ∼20-60% greater tensile and shear stresses and strains, and ∼30% larger posterior deformations in the lamina cribrosa and peripapillary sclera. CONCLUSIONS The cable-in-solid approach can easily be implemented into commercial FE packages to simulate the heterogeneous and anisotropic mechanical properties of collagenous biological tissues.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
| | | | - Reza Razaghi
- Research Department, Heel of Scene Ltd., Tokyo, Japan
| | - Christopher A Girkin
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - J Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
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29
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Liu C, Li Y, Wang M, Li J, Wang N, Zhang F. Changes in intraocular pressure and ocular pulse amplitude of rhesus macaques after blue light scleral cross-linking. BMC Ophthalmol 2022; 22:87. [PMID: 35193527 PMCID: PMC8864789 DOI: 10.1186/s12886-022-02306-0] [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: 03/21/2020] [Accepted: 02/08/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Scleral cross-linking can enhance the biomechanical strength of the sclera and is expected to be a new operative method for the prevention of myopia. However, studies investigating the changes in intraocular pressure (IOP) and ocular pulse amplitude (OPA) after blue light-riboflavin induced scleral collagen cross-linking (SXL) in rhesus monkeys are limited. This study aimed to investigate the changes in IOP and OPA in three-year-old rhesus macaques 1 week, 1 month, and 3 months after blue light-riboflavin SXL. METHODS Seven three-year-old rhesus macaques (14 eyes) were randomly divided into two groups, with 4 monkeys in group A (8 eyes) and 3 monkeys in group B (6 eyes). The right eye of each rhesus macaque was used as the experimental eye, whereas the left eye was used as the control. In group A, one quadrant of each right eye was irradiated. In group B, two quadrants of each right eye and one quadrant of each left eye were irradiated. The IOP and OPA of both eyes were measured in all seven rhesus macaques before SXL and 1 week, 1 month, and 3 months postoperatively, and differences in the IOP and OPA between the experimental and control eyes were evaluated via the paired t test. RESULTS In groups A and B, there were no significant differences between the experimental and control eyes in the IOP or OPA before SXL or 1 week, 1 month, or 3 months postoperatively (P > 0.05). CONCLUSIONS The IOP and OPA are not significantly affected in 1 vs 0 or in 1 vs 2 quadrants of blue light SXL.
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Affiliation(s)
- Chong Liu
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Yu Li
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Mengmeng Wang
- Hebei Ophthalmology Key Lab, Hebei Provincial Eye Hospital, Xingtai, Hebei Province China
| | - Jing Li
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Ningli Wang
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Fengju Zhang
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
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30
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Baumann B, Merkle CW, Augustin M, Glösmann M, Garhöfer G. Pulsatile tissue deformation dynamics of the murine retina and choroid mapped by 4D optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2022; 13:647-661. [PMID: 35284183 PMCID: PMC8884196 DOI: 10.1364/boe.445093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/20/2021] [Accepted: 12/28/2021] [Indexed: 05/11/2023]
Abstract
Irregular ocular pulsatility and altered mechanical tissue properties are associated with some of the most sight-threatening eye diseases. Here we present 4D optical coherence tomography (OCT) for the quantitative assessment and depth-resolved mapping of pulsatile dynamics in the murine retina and choroid. Through a pixel-wise analysis of phase changes of the complex OCT signal, we reveal spatiotemporal displacement characteristics across repeated frame acquisitions. We demonstrate in vivo fundus elastography (FUEL) imaging in wildtype mouse retinas and in a mouse model of retinal neovascularization and uncover subtle structural deformations related to ocular pulsation. Our data in mouse eyes hold promise for a powerful retinal elastography technique that may enable a new paradigm of OCT-based measurements and image contrast.
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Affiliation(s)
- Bernhard Baumann
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna,
Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Conrad W. Merkle
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna,
Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Marco Augustin
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna,
Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Martin Glösmann
- Core Facility for Research and Technology,
University of Veterinary Medicine Vienna,
Veterinärplatz 1, 1210 Vienna, Austria
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology,
Medical University of Vienna, Währinger
Gürtel 18-20, 1090 Vienna, Austria
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31
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Shalaby WS, Ahmed OM, Waisbourd M, Katz LJ. A Review of Potential Novel Glaucoma Therapeutic Options Independent of Intraocular Pressure. Surv Ophthalmol 2021; 67:1062-1080. [PMID: 34890600 DOI: 10.1016/j.survophthal.2021.12.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 12/01/2021] [Accepted: 12/06/2021] [Indexed: 02/06/2023]
Abstract
Glaucoma, a progressive optic neuropathy characterized by retinal ganglion cell degeneration and visual field loss, is the leading cause of irreversible blindness worldwide. Intraocular pressure (IOP) is presently the only modifiable risk factor demonstrated to slow or halt disease progression; however, glaucomatous damage persists in almost 50% of patients despite significant IOP reduction. Many studies have investigated the non-IOP-related risk factors that contribute to glaucoma progression as well as interventions that can prevent or delay glaucomatous neurodegeneration and preserve vision throughout life, independently of IOP. A vast number of experimental studies have reported effective neuroprotection in glaucoma, and clinical studies are ongoing attempting to provide strong evidence of effectiveness of these interventions. In this review, we look into the current understanding of the pathophysiology of glaucoma and explore the recent advances in non-IOP related strategies for neuroprotection and neuroregeneration in glaucoma.
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Key Words
- AMD, Age-related macular degeneration
- BDNF, Brain derived neurotrophic factor
- CNTF, Ciliary neurotrophic factor
- GDNF, Glial‐derived neurotrophic factor
- Glaucoma
- IOP, Intraocular pressure
- LoGTS, Low-Pressure Glaucoma Treatment Study
- MRI, Magnetic resonance imaging
- MSCs, Mesenchymal stem cells
- NGF, Nerve growth factor
- NTG, Normal tension glaucoma
- OCTA, Optical coherence tomography angiography
- PBM, hotobiomodulation
- PDGF, Platelet derived growth factor
- POAG, Primary open angle glaucoma
- RGCs, Retinal ganglion cells
- TNF-α, Tumor necrosis factor- α
- bFGF, Basic fibroblast growth factor
- gene therapy
- intracranial pressure
- intraocular pressure
- neuroprotection
- ocular blood flow
- oxidative stress
- retinal ganglion cells
- stem cell therapy
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Affiliation(s)
- Wesam Shamseldin Shalaby
- Glaucoma Research Center, Wills Eye Hospital, Philadelphia, PA, USA; Department of Ophthalmology, Tanta Medical School, Tanta University, Tanta, Gharbia, Egypt
| | - Osama M Ahmed
- Glaucoma Research Center, Wills Eye Hospital, Philadelphia, PA, USA; Yale University School of Medicine, New Haven, CT, USA
| | - Michael Waisbourd
- Glaucoma Research Center, Wills Eye Hospital, Philadelphia, PA, USA; Department of Ophthalmology, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - L Jay Katz
- Glaucoma Research Center, Wills Eye Hospital, Philadelphia, PA, USA.
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32
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Hu D, Jiang J, Ding B, Xue K, Sun X, Qian S. Mechanical Strain Regulates Myofibroblast Differentiation of Human Scleral Fibroblasts by YAP. Front Physiol 2021; 12:712509. [PMID: 34658907 PMCID: PMC8514697 DOI: 10.3389/fphys.2021.712509] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/30/2021] [Indexed: 12/14/2022] Open
Abstract
Scleral extracellular matrix (ECM) remodeling is thought to play a critical role in the pathogenesis of glaucoma. Mechanical strain induced by elevated intraocular pressure can promote myofibroblast differentiation of fibroblasts and result in scleral ECM remodeling; however, the underlying mechanism remains poorly understood. Yes-associated protein (YAP) is a mechanosensory protein and the key downstream transcriptional effector of the Hippo signaling pathway. Here, we investigated the role of YAP in mechanical strain-induced myofibroblast transformation during glaucoma scleral ECM remodeling. Integrative bioinformatics analyses were performed to identify the key pathways for the ECM remodeling of the sclera in glaucoma. Sprague–Dawley rats were used to establish a chronic ocular hypertension model, and the expression of collagen type I (COL1) and YAP in the sclera was analyzed by immunohistochemical analysis and Western blotting. Furthermore, human scleral fibroblasts (HSFs) were cultured and subjected to mechanical strain. In groups with or without the YAP siRNA or YAP inhibitor, cell proliferation, migration capacity, and the expression levels of YAP, COL1, and α-smooth muscle actin (α-SMA) were evaluated by Cell Counting Kit-8 assay, scratch assay, and Western blotting. The interactions between YAP and Smad3 were demonstrated by coimmunoprecipitation, and the expression levels of COL1 and α-SMA were evaluated in groups treated with or without the Smad3 inhibitor. We first revealed that the Hippo signaling pathway may be involved in mechanical strain-induced scleral ECM remodeling through bioinformatics analysis. Furthermore, the in vivo study showed upregulated YAP, COL1, and α-SMA expression in the hypertensive sclera of rats. In vitro, mechanical strain increased YAP and COL1 expression in HSFs and promoted myofibroblast differentiation. After YAP knockdown or inhibition with verteporfin, mechanical strain-induced fibrotic changes in HSFs were markedly suppressed. Additionally, YAP showed a protein interaction with Smad3, and the upregulation of a-SMA and COL1 in response to mechanical strain was also significantly downregulated following the inhibition of Smad3. In conclusion, mechanical strain activated scleral myofibroblast differentiation via YAP. The YAP pathway may play an important role in regulating scleral myofibroblast differentiation and ECM remodeling of the sclera in glaucoma.
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Affiliation(s)
- Di Hu
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China.,Department of Ophthalmology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Junhong Jiang
- The Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Baiyang Ding
- Spine Research Center of Wannan Medical College, Wuhu, China
| | - Kang Xue
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China.,State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Shaohong Qian
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
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33
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Kazemi A, Zhou B, Zhang X, Sit AJ. Comparison of Corneal Wave Speed and Ocular Rigidity in Normal and Glaucomatous Eyes. J Glaucoma 2021; 30:932-940. [PMID: 34127628 PMCID: PMC8484019 DOI: 10.1097/ijg.0000000000001901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/06/2021] [Indexed: 11/26/2022]
Abstract
PRECIS Ocular biomechanics were compared between treated glaucoma patients and healthy subjects matched for age, intraocular pressure (IOP), and axial length. There was no difference in corneal wave propagation speed, but ocular rigidity was lower in glaucomatous eyes. PURPOSE Ocular biomechanical properties are important in understanding glaucoma pathogenesis but the affected tissues are unclear. In this study, we compared corneal wave speed (a measure of corneal elasticity) and ocular rigidity coefficient between glaucomatous and normal eyes. MATERIALS AND METHODS Twenty glaucomatous eyes from 10 patients and 20 normal eyes from 13 controls, matched for age, IOP, and axial length were included. Ocular rigidity was calculated based on the difference in supine IOP by pneumatonometry with and without a 10-g weight. Corneal wave speed was determined by ultrasound surface wave elastography. A small, 0.1-second harmonic vibration at 100 Hz was generated through the closed eyelids. Wave propagation was captured by an ultrasound transducer, and wave speed was determined from the phase change with distance. Comparisons were performed using generalized estimating equation models. RESULTS There were no significant differences in corneal wave speed between glaucomatous and normal eyes (2.16±0.25 vs. 2.07±0.16 m/s, P=0.17). However, ocular rigidity was significantly lower in glaucomatous eyes (0.0218±0.0033 vs. 0.0252±0.0050/μL, P=0.01). Corneal wave speed was not correlated with age and IOP in either group (P≥0.23) but was correlated with ocular rigidity (R=0.48, P=0.02) and inversely correlated with axial length (R=-0.53, P=0.01) in glaucomatous eyes. CONCLUSION Glaucomatous eyes tend to have lower ocular rigidity than healthy eyes with similar age, IOP, and axial length. However, the lack of a difference in corneal wave speed suggests that corneal tissue may not be significantly affected, and scleral changes likely play a more important role in glaucoma.
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Affiliation(s)
- Arash Kazemi
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
| | - Boran Zhou
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Xiaoming Zhang
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Arthur J. Sit
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
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34
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Yahalomi T, Kovalyuk N, Arnon R, Hen B, Pikkel J. The effect of central corneal thickness on Goldmann tonometry: a retrospective study. Int Ophthalmol 2021; 42:253-259. [PMID: 34554360 DOI: 10.1007/s10792-021-02021-7] [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: 07/15/2021] [Accepted: 09/11/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE To determine the relation between central corneal thickness and intraocular pressure. PATIENTS AND METHODS This retrospective study investigated 112 eyes from 56 individuals who underwent photorefractive keratectomy in a single private medical center between May 2018 and September 2019. Intraocular pressure readings were obtained with Goldmann applanation tonometry, and central corneal thickness measurements were evaluated preoperatively. All the examinations were repeated at 3 and 6 months postoperative. RESULTS At 3 and 6 months postoperative, the mean intraocular pressure was only slightly reduced from baseline (mean reduction of 0.6 ± 2.0 mmHg, P < 0.001 and 0.73 ± 2.14 mmHg, P < 0.001, respectively). The change in intraocular pressure following photorefractive keratectomy was not clinically significant, and this change was not correlated with postoperative central corneal thickness at 3 months (p = 0.620, r = 0.047). CONCLUSION This study showed that the change in intraocular pressure following photorefractive keratectomy was not clinically significant, and ruled out a correlation in this context between the change in central corneal thickness and the delta intraocular pressure. Our results might question the axiom between central corneal thickness and intraocular pressure and may thus challenge the current clinical setting for evaluating glaucoma.
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Affiliation(s)
- Tal Yahalomi
- Department of Ophthalmology, Faculty of Health Sciences, Samson Assuta Ashdod Hospital, Ben-Gurion University of the Negev, Beersheba, Israel.
| | - Natalya Kovalyuk
- Department of Ophthalmology, Faculty of Health Sciences, Samson Assuta Ashdod Hospital, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Roee Arnon
- Department of Ophthalmology, Faculty of Health Sciences, Samson Assuta Ashdod Hospital, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Barak Hen
- Department of Ophthalmology, Faculty of Health Sciences, Samson Assuta Ashdod Hospital, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Joseph Pikkel
- Department of Ophthalmology, Faculty of Health Sciences, Samson Assuta Ashdod Hospital, Ben-Gurion University of the Negev, Beersheba, Israel
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35
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Park SA, Komáromy AM. Biomechanics of the optic nerve head and sclera in canine glaucoma: A brief review. Vet Ophthalmol 2021; 24:316-325. [PMID: 34402566 DOI: 10.1111/vop.12923] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 06/04/2021] [Accepted: 07/25/2021] [Indexed: 01/17/2023]
Abstract
Glaucoma is a leading cause of irreversible blindness, a progressive optic neuropathy with retinal ganglion cell (RGC) death beginning in the optic nerve head (ONH). A primary risk factor for developing glaucoma is elevated intraocular pressure (IOP). Reducing IOP is the only treatment proven to be effective at delaying disease progression. Nevertheless, even when patients have their IOP reduced, the majority of them continue to lose vision. There are, in both humans and dogs, significant interindividual variabilities in susceptibilities to IOP-induced optic nerve damage. Vision loss progresses much more slowly in Beagles with open-angle glaucoma (OAG) caused by ADAMTS10 mutation. This can be attributed to the mutation-related altered ocular biomechanical properties. The principal site of optic nerve (ON) damage in glaucoma is the ONH. It is suggested that the biomechanical properties of the ONH and the surrounding peripapillary sclera (PPS) contribute to glaucoma development and progression. As far as the beneficial biomechanical properties of the ONH and PPS for a decreased susceptibility and slow progression of glaucoma, data are inconsistent and conflicting. Recent biomechanical studies on beagles with ADAMTS10 mutation demonstrated that the mutant dogs have mechanically weak posterior sclera. This weakness was associated with a reduced collagen density and a lower proportion of insoluble collagen. These changes, observed before glaucoma development, were considered intrinsic characteristics caused by the mutation rather than a secondary effect of IOP elevation. Further studies of ADAMTS10-OAG may elucidate the effects of altered biomechanical properties of ONH and PPS in determining the glaucoma progression.
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Affiliation(s)
- Shin Ae Park
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, USA
| | - András M Komáromy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
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36
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Hatami-Marbini H, Pachenari M. Tensile Viscoelastic Properties of the Sclera after Glycosaminoglycan Depletion. Curr Eye Res 2021; 46:1299-1308. [PMID: 34325593 DOI: 10.1080/02713683.2021.1874026] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE Fibrillar collagen network and glycosaminoglycans (GAGs) are the primary components of extracellular matrix (ECM) of the sclera. The main goal of this study was to investigate the possible structural roles of GAGs in the scleral tensile properties as a function of preconditioning and displacement rate. METHODS Four-step uniaxial stress-relaxation tests were used for characterizing the viscoelastic tensile response of the posterior porcine sclera with and without enzymatic GAG removal. The scleral strips were divided into different groups based on the displacement rate and the presence or absence of a preconditioning step in the loading protocol. The groups were (1) displacement rate of 0.2 mm/min without preconditioning, (2) displacement rate of 1 mm/min without preconditioning, (3) displacement rate of 0.2 mm/min with preconditioning, and (4) displacement rate of 1 mm/min with preconditioning. The peak stress, equilibrium stress, and the equilibrium elastic modulus were calculated for all specimens and compared against each other. RESULTS Increasing the displacement rate from 0.2 mm/min to 1.0 mm/min was found to cause an insignificant change in the equilibrium stress and equilibrium elastic modulus of porcine scleral strips. Removal of GAGs resulted in an overall stiffer tensile behavior independent of the displacement rate in samples that were not preconditioned (P < .05). The behavior of preconditioned samples with and without GAG removal was not significantly different from each other. CONCLUSIONS The experimental measurements of the present study showed that GAGs play an important role in the mechanical properties of the posterior porcine sclera. Furthermore, using a preconditioning step in the uniaxial testing protocol resulted in not being able to identify any significant difference in the tensile behavior of GAG depleted and normal scleral strips.
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Affiliation(s)
- Hamed Hatami-Marbini
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA
| | - Mohammad Pachenari
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA
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37
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Corneal Biomechanical Changes Caused by Acute Elevation of IOP in Eyes with and without Glaucoma. Optom Vis Sci 2021; 98:367-373. [PMID: 33828042 DOI: 10.1097/opx.0000000000001668] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SIGNIFICANCE Although corneal biomechanical parameters are well linked with glaucoma, their clinical utility has not yet been fully elucidated. This study was designed to provide unique evidence about the dynamic nature of corneal biomechanical parameters and their potential prognostic ability for glaucoma. PURPOSE This study aimed to evaluate the effect of acute intraocular pressure (IOP) elevation on corneal hysteresis (CH) and corneal resistance factor (CRF) and the associations of these biomechanical parameters with glaucomatous disease. METHODS Subjects participating in a prospective, longitudinal glaucoma research study had CH and CRF measured before and during ophthalmodynamometry during visits in the years 2011 to 2012. All participants were diagnosed with primary open-angle glaucoma, ocular hypertension, glaucoma suspect, or normal eyes and had a minimum of 3 years of study participation with at least five reliable visual field (VF) tests. Changes in CH, CRF, and IOP induced by ophthalmodynamometry were compared between diagnostic groups and evaluated for relationships with existing and future glaucomatous VF loss. RESULTS In 248 eyes of 248 subjects followed up for 7.7 ± 2.3 years, ophthalmodynamometry induced a mean IOP increase from 15.1 to 29.9 mmHg, causing a mean 34 ± 28% increase in CRF and 21 ± 25% decrease in CH. Magnitude of CH change did not differ between diagnostic groups or between eyes that did (n = 20) and did not (n = 95) develop new VF loss during the study period, nor was it related to rate of future VF progression. CONCLUSIONS Ophthalmodynamometry-induced IOP elevation resulted in significant acute changes in CH and CRF in this study; this suggests accounting for IOP may be important in clinical interpretation of these parameters. However, because the degree of CH change was not related to glaucoma or its progression, acute changes in CH and CRF do not seem to have a prognostic value for glaucoma.
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38
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Ma Y, Moroi SE, Roberts CJ. Non-invasive Clinical Measurement of Ocular Rigidity and Comparison to Biomechanical and Morphological Parameters in Glaucomatous and Healthy Subjects. Front Med (Lausanne) 2021; 8:701997. [PMID: 34291068 PMCID: PMC8287026 DOI: 10.3389/fmed.2021.701997] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/07/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To assess ocular rigidity using dynamic optical coherence tomography (OCT) videos in glaucomatous and healthy subjects, and to evaluate how ocular rigidity correlates with biomechanical and morphological characteristics of the human eye. Methods: Ocular rigidity was calculated using Friedenwald's empirical equation which estimates the change in intraocular pressure (IOP) produced by volumetric changes of the eye due to choroidal pulsations with each heartbeat. High-speed OCT video was utilized to non-invasively measure changes in choroidal volume through time-series analysis. A control-case study design was based on 23 healthy controls and 6 glaucoma cases. Multiple diagnostic modalities were performed during the same visit including Spectralis OCT for nerve head video, Pascal Dynamic Contour Tonometry for IOP and ocular pulse amplitude (OPA) measurement, Corvis ST for measuring dynamic biomechanical response, and Pentacam for morphological characterization. Results: Combining glaucoma and healthy cohorts (n = 29), there were negative correlations between ocular rigidity and axial length (Pearson R = −0.53, p = 0.003), and between ocular rigidity and anterior chamber volume (R = −0.64, p = 0.0002). There was a stronger positive correlation of ocular rigidity and scleral stiffness (i.e., stiffness parameter at the highest concavity [SP-HC]) (R = 0.62, p = 0.0005) compared to ocular rigidity and corneal stiffness (i.e., stiffness parameter at the first applanation [SP-A1]) (R = 0.41, p = 0.033). In addition, there was a positive correlation between ocular rigidity and the static pressure-volume ratio (P/V ratio) (R = 0.72, p < 0.0001). Conclusions: Ocular rigidity was non-invasively assessed using OCT video and OPA in a clinic setting. The significant correlation of ocular rigidity with biomechanical parameters, SP-HC and P/V ratio, demonstrated the validity of the ocular rigidity measurement. Ocular rigidity is driven to a greater extent by scleral stiffness than corneal stiffness. These in vivo methods offer an important approach to investigate the role of ocular biomechanics in glaucoma.
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Affiliation(s)
- Yanhui Ma
- Department of Ophthalmology and Visual Sciences, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Sayoko E Moroi
- Department of Ophthalmology and Visual Sciences, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Cynthia J Roberts
- Department of Ophthalmology and Visual Sciences, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
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39
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Sayah DN, Mazzaferri J, Descovich D, Costantino S, Lesk MR. The Association Between Ocular Rigidity and Neuroretinal Damage in Glaucoma. Invest Ophthalmol Vis Sci 2021; 61:11. [PMID: 33151280 PMCID: PMC7671866 DOI: 10.1167/iovs.61.13.11] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Ocular rigidity (OR) is an important biomechanical property, thought to be relevant in the pathophysiology of open-angle glaucoma (OAG). This study aims to evaluate the relationship between OR and neuroretinal damage caused by glaucoma. Methods One hundred eight subjects (22 with healthy eyes, 23 with suspect discs, and 63 with OAG) were included in this study. OR was measured using a noninvasive optical coherence tomography (OCT)-based method developed by our group. We also measured central corneal thickness (CCT), corneal hysteresis (CH), and corneal resistance factor (CRF). Pearson and partial correlations were performed to evaluate the relationship between OR and glaucomatous damage represented by ganglion cell complex (GCC), retinal nerve fiber layer (RNFL) thicknesses, and neuroretinal rim area. Results Significant positive correlations were found between OR and minimum GCC thickness (r = 0.325, P = 0.001), average GCC thickness (r = 0.320, P = 0.002), rim area (r = 0.344, P < 0.001), and RNFL thickness in the superior (r = 0.225, P = 0.023), and inferior (r = 0.281, P = 0.004) quadrants. These correlations were generally greater than those found for CCT, CH, and CRF. Furthermore, no correlation was found between OR and corneal biomechanical parameters. After adjusting for age, sex, and ethnicity, significant correlations were found between OR and minimum and average GCC thickness (r = 0.357, P = 0.001 and r = 0.344, P = 0.001, respectively), rim area (r = 0.327, P = 0.001), average RNFL thickness (r = 0.331, P = 0.001), and RNFL thickness in the superior (r = 0.296, P = 0.003) and inferior (r = 0.317, P = 0.001) quadrants. Conclusions In this study, we found a positive correlation between structural OCT-based parameters and OR, indicating more neuroretinal damage in eyes with lower OR. These findings could provide insight into the pathophysiology of OAG.
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Affiliation(s)
- Diane N Sayah
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Javier Mazzaferri
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | - Denise Descovich
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | - Santiago Costantino
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.,Centre Universitaire d'ophtalmologie de l'Université de Montréal de l'Hôpital Maisonneuve-Rosemont, CIUSSS-E, Montreal, Quebec, Canada
| | - Mark R Lesk
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.,Centre Universitaire d'ophtalmologie de l'Université de Montréal de l'Hôpital Maisonneuve-Rosemont, CIUSSS-E, Montreal, Quebec, Canada
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40
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Baptista PM, Ambrosio R, Oliveira L, Meneres P, Beirao JM. Corneal Biomechanical Assessment with Ultra-High-Speed Scheimpflug Imaging During Non-Contact Tonometry: A Prospective Review. Clin Ophthalmol 2021; 15:1409-1423. [PMID: 33854295 PMCID: PMC8039844 DOI: 10.2147/opth.s301179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/05/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In recent years, increasing interest has arisen in the application of data from corneal biomechanics in many areas of ophthalmology, particularly to assist in the detection of early corneal ectasia or ectasia susceptibility, to predict corneal response to surgical or therapeutic interventions and in glaucoma management. Technology has evolved and, recently, the Scheimpflug principle was associated with a non-contact air-puff tonometer, allowing a thorough analysis of corneal biomechanics and a biomechanically corrected intraocular pressure assessment, opening up new perspectives both in ophthalmology and in other medical areas. Data from corneal biomechanics assessment are being integrated in artificial intelligence models in order to increase its value in clinical practice. OBJECTIVE To review the state of the art in the field of corneal biomechanics assessment with special emphasis to the technology based on ultra-high-speed Scheimpflug imaging during non-contact tonometry. SUMMARY A meticulous literature review was performed until the present day. We used 136 published manuscripts as our references. Both information from healthy individuals and descriptions of possible associations with systemic diseases are described. Additionally, it exposed information regarding several fields of ocular pathology, from cornea and ocular surface through areas of refractive surgery and glaucoma until vascular and structural diseases of the chorioretinal unit.
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Affiliation(s)
- Pedro Manuel Baptista
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Porto, Portugal
| | - Renato Ambrosio
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, RJ, Brazil
- Department of Cornea and Refractive Surgery, Instituto de Olhos Renato Ambrósio, Rio de Janeiro, Brazil
- Department of Opthalmology, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
- Federal University of São Paulo (UNIFESP), São Paulo, Brazil
- Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil
| | - Luis Oliveira
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Pedro Meneres
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Porto, Portugal
| | - Joao Melo Beirao
- Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Porto, Portugal
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Girkin CA, Belghith A, Bowd C, Medeiros FA, Weinreb RN, Liebmann JM, Proudfoot JA, Zangwill LM, Fazio MA. Racial Differences in the Rate of Change in Anterior Lamina Cribrosa Surface Depth in the African Descent and Glaucoma Evaluation Study. Invest Ophthalmol Vis Sci 2021; 62:12. [PMID: 33844828 PMCID: PMC8039570 DOI: 10.1167/iovs.62.4.12] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to determine if the rate of change in the depth of the surface of the lamina cribrosa due to glaucomatous remodeling differs between glaucoma patients of African descent (AD) and European descent (ED). Methods There were 1122 images taken longitudinally over an average of 3 years (range = 0.9-4.1 years) from 122 patients with glaucoma followed in the African Descent and Glaucoma Evaluation Study (ADAGES) and Diagnostic Intervention and Glaucoma Study (DIGS) were automatically segmented to compute anterior lamina cribrosa surface depth (ALCSD). The rate of ALCSD change was compared across racial groups after adjusting for baseline characteristics known to be associated with ALCSD or disease progression (visual field, ALCSD, corneal thickness, optic disk size, and age). Results After adjusting for all other covariates, the ED group had significantly greater ALCSD posterior migration (deepening) than the AD group (difference = 2.57 µm/year, P = 0.035). There was a wider range of ALCSD change in the ED compared with the AD group, and more individuals had greater magnitude of both deepening and shallowing. No other covariates measured at baseline had independent effects on the longitudinal changes in ALCSD (baseline visual field severity, baseline ALCSD, corneal thickness, Bruch's membrane opening [BMO] area, or age). Conclusions Glaucomatous remodeling of the lamina cribrosa differs between AD and ED patients with glaucoma. Unlike the cross-sectional associations seen with aging, in which a deeper ALCSD was seen with age in the ED group, glaucomatous remodeling in this longitudinal study resulted in more posterior migration of ALCSD in ED compared to AD patients.
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Affiliation(s)
- Christopher A Girkin
- Department of Ophthalmology and Visual Science, School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Akram Belghith
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California, United States
| | - Christopher Bowd
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California, United States
| | - Felipe A Medeiros
- Duke Eye Center and Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California, United States
| | - Jeffrey M Liebmann
- Bernard and Shirlee Brown Glaucoma Research Laboratory, Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, New York, United States
| | - James A Proudfoot
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California, United States
| | - Linda M Zangwill
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California, United States
| | - Massimo A Fazio
- Department of Ophthalmology and Visual Science, School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States.,Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, California, United States.,Department of Biomedical Engineering, School of Engineering, The University of Alabama at Birmingham, Birmingham, Alabama, United States
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Pachenari M, Hatami-Marbini H. Regional Differences in the Glycosaminoglycan Role in Porcine Scleral Hydration and Mechanical Behavior. Invest Ophthalmol Vis Sci 2021; 62:28. [PMID: 33749719 PMCID: PMC7991977 DOI: 10.1167/iovs.62.3.28] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose This study characterized the role of glycosaminoglycans (GAGs) in the hydration, thickness, and biomechanical properties of posterior and anterior porcine sclera. Methods The scleral discs and strips were obtained from the anterior and posterior parts of porcine eyes, and their initial hydration and thickness were measured. The anterior and posterior scleral discs were used to show the efficacy of the GAG removal protocol by quantifying their GAG content. The strips were divided into three groups of PBS treatment, buffer treatment, and enzyme treatment in order to assess the effects of different treatment procedures on the thickness, hydration, and viscoelastic properties of the samples. The mechanical properties of the strips were determined by performing uniaxial tensile stress relaxation experiments. Results It was found that the control and buffer groups had insignificant differences in all measured quantities. The samples from the posterior region had a significantly larger GAG content and thickness in comparison with those from anterior region; however, there was an insignificant difference in their hydration. The GAG depletion process decreased the hydration of both anterior and posterior samples significantly (P < 0.05). Furthermore, the mechanical tests showed that the removal of GAGs resulted in stiffer mechanical behavior in both anterior and posterior samples (P < 0.05). In particular, the peak stress and equilibrium stress were significantly larger for the strips in the enzyme treatment group. Conclusions GAGs and their interaction with the collagen network are important in defining the hydration and mechanical properties of both posterior and anterior sclera.
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Affiliation(s)
- Mohammad Pachenari
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Hamed Hatami-Marbini
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, Illinois, United States
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Calkins DJ. Adaptive responses to neurodegenerative stress in glaucoma. Prog Retin Eye Res 2021; 84:100953. [PMID: 33640464 DOI: 10.1016/j.preteyeres.2021.100953] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/08/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Glaucoma causes loss of vision through degeneration of the retinal ganglion cell (RGC) projection to the brain. The disease is characterized by sensitivity to intraocular pressure (IOP) conveyed at the optic nerve head, through which RGC axons pass unmyelinated to form the optic nerve. From this point, a pathogenic triumvirate comprising inflammatory, oxidative, and metabolic stress influence both proximal structures in the retina and distal structures in the optic projection. This review focuses on metabolic stress and how the optic projection may compensate through novel adaptive mechanisms to protect excitatory signaling to the brain. In the retina and proximal nerve head, the unmyelinated RGC axon segment is energy-inefficient, which leads to increased demand for adenosine-5'-triphosphate (ATP) at the risk of vulnerability to Ca2+-related metabolic and oxidative pressure. This vulnerability may underlie the bidirectional nature of progression. However, recent evidence highlights that the optic projection in glaucoma is not passive but rather demonstrates adaptive processes that may push back against neurodegeneration. In the retina, even as synaptic and dendritic pruning ensues, early progression involves enhanced excitability of RGCs. Enhancement involves depolarization of the resting membrane potential and increased response to light, independent of RGC morphological type. This response is axogenic, arising from increased levels and translocation of voltage-gated sodium channels (NaV) in the unmyelinated segment. During this same early period, large-scale networks of gap-junction coupled astrocytes redistribute metabolic resources to the optic projection stressed by elevated IOP to slow loss of axon function. This redistribution may reflect more local remodeling, as astrocyte processes respond to focal metabolic duress by boosting glycogen turnover in response to axonal activity in an effort to promote survival of the healthiest axons. Both enhanced excitability and metabolic redistribution are transient, indicating that the same adaptive mechanisms that apparently serve to slow progression ultimately may be too expensive for the system to sustain over longer periods.
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Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute, Nashville, TN, USA; Vanderbilt Vision Research Center, Vanderbilt University Medical Center, 1161 21st Ave S, AA7100 Medical Center North Nashville, Tennessee, 37232, USA.
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Changes in Corneal Biomechanics and Glaucomatous Visual Field Loss. J Glaucoma 2021; 30:e246-e251. [PMID: 33596020 DOI: 10.1097/ijg.0000000000001819] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 01/25/2021] [Indexed: 11/25/2022]
Abstract
PRECIS A lower baseline corneal hysteresis and a decrease in corneal resistance factor (CRF) over time are associated with higher risk of visual field progression in glaucomatous and glaucoma suspect eyes. PURPOSE The aim was to investigate the longitudinal change in CRF and cornea hysteresis (CH) as risk factors for visual field progression. MATERIALS AND METHODS In this prospective observational cohort study, 72 eyes of 48 glaucoma or glaucoma suspect patients were followed for an average of 4.5 years. Baseline and follow-up CH and CRF measurements were performed with the Ocular Response Analyzer (Reichert Ophthalmic Instruments Inc., Depew, N.Y.). Evaluation of rates of visual field change during follow-up was performed using visual field mean deviation. Univariable and multivariable linear mixed models assessed the relationship of visual field progression with baseline CRF and CH as well as with changes in CRF and CH. RESULTS The mean baseline CH was 9.0 (95% confidence interval: 8.6-9.4) mm Hg and the mean baseline CRF was 9.3 (95% confidence interval: 8.8-9.9) mm Hg. There was no statistically significant difference in average CH and CRF measurements over time. In multivariable modeling adjusting for age, race, and mean intraocular pressure during follow-up, each 1 mm Hg lower in baseline CH and 1 mm Hg decrease in CRF over time were associated with a 0.12 (P=0.042) and 0.14 dB/year (P=0.007) faster rate of visual field mean deviation loss, respectively. Similar findings were found in glaucoma eyes but not found in glaucoma suspect eyes. CONCLUSION Visual field progression was associated with a lower baseline CH and a decrease in CRF over time. Assessment of corneal resistance and elasticity at baseline and during follow-up examinations should be considered to identify those eyes at highest risk of visual field progression.
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Kim YC, Koo YH, Bin Hwang H, Kang KD. The Shape of Posterior Sclera as a Biometric Signature in Open-angle Glaucoma: An Intereye Comparison Study. J Glaucoma 2021; 29:890-898. [PMID: 32555059 PMCID: PMC7647446 DOI: 10.1097/ijg.0000000000001573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Supplemental Digital Content is available in the text. Purpose: To characterize intereye differences in posterior segment parameters and determine their significance in open-angle glaucoma patients with unilateral damage. Methods: Both eyes from 65 subjects without any nerve damage and 43 patients undergoing treatment for unilateral open-angle glaucoma were included in this study. A 12.0×9.0×2.6 mm volume of the posterior segment in each eye was scanned with swept-source optical coherence tomography. Coronally reconstructed optical coherence tomography images were analyzed to determine the deepest point of the eye (DPE), which we then calculated the distance (Disc-DPE distance), depth (Disc-DPE depth), angle (Disc-DPE angle) from the optic disc center to the DPE. Posterior pole shape was analyzed measuring the posterior pole-cross-sectional area, posterior pole-horizontal width (PP-HW), and posterior pole-vertical width) of the posterior pole. These measurements and their intereye absolute difference (IAD; absolute difference in measurements between the right and left eyes) values were compared between the healthy and unilateral glaucomatous patients. Results: The posterior sclera measurements, including the Disc-DPE distance, Disc-DPE depth, and posterior pole-cross-sectional area, were significantly different between the unilateral glaucoma eyes and contralateral healthy eyes (P=0.043, P=0.035, and P=0.049, respectively). By contrast, none of the intereye differences in optic nerve head parameters were significant in the unilateral glaucoma patients. In comparison with the IAD values, the baseline intraocular pressure and PP-HW of the posterior segment showed significant differences between the healthy and the unilateral glaucoma patients (P=0.019 and P=0.036, respectively). A multivariate analysis showed that a larger baseline intraocular pressure IAD [odds ratio (OR), 1.381; P=0.009)] and larger PP-HW IAD (OR, 1.324; P=0.032) were significantly associated with the presence of glaucoma. Conclusions: Compared with the fellow healthy eyes, glaucomatous eyes had larger and more steeply curved posterior poles, which represent a structural variation of the posterior sclera that might be associated with glaucomatous optic neuropathy.
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Affiliation(s)
- Yong Chan Kim
- Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Incheon St. Mary's Hospital, Incheon
| | - Yong Ho Koo
- Department of Ophthalmology, College of medicine, Chuncheon Sacred Heart Hospital, Hallym University, Chuncheon-si, Gangwon-do, Republic of Korea
| | - Hyung Bin Hwang
- Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Incheon St. Mary's Hospital, Incheon
| | - Kui Dong Kang
- Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Incheon St. Mary's Hospital, Incheon
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Szeto J, Chow A, McCrea L, Mozzer A, Nguyen TD, Quigley HA, Pitha I. Regional Differences and Physiologic Behaviors in Peripapillary Scleral Fibroblasts. Invest Ophthalmol Vis Sci 2021; 62:27. [PMID: 33502460 PMCID: PMC7846956 DOI: 10.1167/iovs.62.1.27] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose The purpose of this study was to describe the cellular architecture of normal human peripapillary sclera (PPS) and evaluate surface topography's role in fibroblast behavior. Methods PPS cryosections from nonglaucomatous eyes were labelled for nuclei, fibrillar actin (FA), and alpha smooth muscle actin (αSMA) and imaged. Collagen fibrils were imaged using second harmonic generation. Nuclear density and aspect ratio of the internal PPS (iPPS), outer PPS (oPPS), and peripheral sclera were determined. FA and αSMA fibril alignment with collagen extracellular matrix (ECM) was determined. PPS fibroblasts were cultured on smooth or patterned membranes under mechanical strain and in the presence of TGFβ1 and 2. Results The iPPS (7.1 ± 2.0 × 10−4, P < 0.0001) and oPPS (5.3 ± 1.4 × 10−4, P = 0.0013) had greater nuclei density (nuclei/µm2) than peripheral sclera (2.5 ± 0.8 × 10−4). The iPPS (2.0 ± 0.3, P = 0.002) but not oPPS (2.4 ± 0.4, P = 0.45) nuclei had smaller aspect ratios than peripheral (2.7 ± 0.5) nuclei. FA was present throughout the scleral stroma and was more aligned with oPPS collagen (9.6 ± 1.9 degrees) than in the peripheral sclera (15.9 ± 3.9 degrees, P =0.002). The αSMA fibers in the peripheral sclera were less aligned with collagen fibrils (26.4 ± 4.8 degrees) than were FA (15.9 ± 3.9 degrees, P = 0.0002). PPS fibroblasts cultured on smooth membranes shifted to an orientation perpendicular to the direction of cyclic uniaxial strain (1 Hz, 5% strain, 42.2 ± 7.1 degrees versus 62.0 ± 8.5 degrees, P < 0.0001), whereas aligned fibroblasts on patterned membranes were resistant to strain-induced reorientation (5.9 ± 1.4 degrees versus 10 ± 3.3 degrees, P = 0.21). Resistance to re-orientation was reduced by TGFβ treatment (10 ± 3.3 degrees without TGFβ1 compared to 23.1 ± 4.5 degrees with TGFβ1, P < 0.0001). Conclusions Regions of the posterior sclera differ in cellular density and nuclear morphology. Topography alters the cellular response to mechanical strain.
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Affiliation(s)
- Julia Szeto
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Amanda Chow
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Liam McCrea
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Ann Mozzer
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Thao D Nguyen
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States.,Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland, United States
| | - Harry A Quigley
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States.,Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Ian Pitha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States.,Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States.,Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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47
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Özkan Aksoy N, Çakır B, Aksoy YE, Demir Boncukçu K, Özmen S, Çelik E, Alagöz G. Effects of glaucoma and central corneal thickness on optic nerve head biomechanics. Int Ophthalmol 2021; 41:1283-1289. [PMID: 33387111 DOI: 10.1007/s10792-020-01686-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 12/19/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate effects of glaucoma and central corneal thickness (CCT) on optic nerve head biomechanics. METHODS Four groups were formed according to CCT measurements and the presence of glaucoma. Glaucomatous patients with thin (< 510 µ) and thick (> 570 µ) corneas composed groups 1 and 3, respectively. Nonglaucomatous patients with thin and thick corneas composed groups 2 and 4, respectively. Real-time elastography (RTE) was performed on all groups, and optic nerve strain rate (ONSR), orbital fat strain rate (OFSR), and strain ratio of orbital fat to the optic nerve and medial and lateral parts of the optic nerve (SROFON, SROFMON, SROFLON, respectively) were obtained and compared between groups. The correlations between CCT and these parameters were also investigated. RESULTS Statistically significant difference was not found between groups in terms of strain rate of optic nerve and orbital fat, SRFON, SROFMON and SROFLON. There was a positive correlation between ONSR and OFSR and mean CCT in patients with CCT thinner than 510 µ (p: 0.03 r: 0.26, p: 0.01 r: 0.32 respectively). CONCLUSION SROFON, SROFLON and SROFMON values did not differ between glaucomatous and nonglaucomatous patients with thin or thick CCTs. The correlations between CCT and OFSR and ONSR were found to be statistically significant in patients with thin CCT.
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Affiliation(s)
- Nilgün Özkan Aksoy
- Department of Ophthalmology, Sakarya University Medical Education and Research Hospital, Sakarya, Turkey.
| | - Burçin Çakır
- Department of Ophthalmology, Sakarya University Medical Education and Research Hospital, Sakarya, Turkey
| | - Yakup Ersel Aksoy
- Department of Ophthalmology, Sakarya University Medical Education and Research Hospital, Sakarya, Turkey
| | - Kadriye Demir Boncukçu
- Department of Ophthalmology, Sakarya University Medical Education and Research Hospital, Sakarya, Turkey
| | - Sedat Özmen
- Department of Ophthalmology, Sakarya University Medical Education and Research Hospital, Sakarya, Turkey
| | - Erkan Çelik
- Department of Ophthalmology, Sakarya University Medical Education and Research Hospital, Sakarya, Turkey
| | - Gürsoy Alagöz
- Department of Ophthalmology, Sakarya University Medical Education and Research Hospital, Sakarya, Turkey
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Caride SG, González LP, Francés FS, Feijoo JG. Study of corneal biomechanical properties in patients with childhood glaucoma. Int J Ophthalmol 2020; 13:1922-1927. [PMID: 33344191 DOI: 10.18240/ijo.2020.12.12] [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: 12/03/2019] [Accepted: 07/15/2020] [Indexed: 11/23/2022] Open
Abstract
AIM To study of corneal biomechanical properties and intraocular pressure (IOP) measured with Corvis Scheimpflug Technology (ST) in patients with childhood glaucoma (CG). METHODS Cross-sectional study in which 89 eyes were included 56 of them with CG. Only one eye per patient was included. The following variables were obtained from the clinical history and the ophthalmological examination: age, sex, IOP, number of surgeries, and the cup/disc ratio (CDR). The following parameters were recorded using Corvis ST: corrected by biomechanics IOP (bIOP), not corrected IOP (nctIOP), central corneal thickness (CCT), maximum concavity [radius, peak distance (PD) and deformation amplitude], applanation 1 and 2 (length and velocity). The mean age was 23±14.55 and 33±19.5 years old for the control group and CG group, respectively. Totally 36 were males and 53 were females. In the CG group, 7 patients were controlled only with medical treatment. Sixteen had at least one previous goniotomy, 19 had at least one trabeculectomy, and 11 had an Ahmed implant. RESULTS A significant and positive intraclass correlation coefficient was found between Goldman IOP and the IOP measured by Corvis in both groups. No differences were found between the IOP measured with Corvis and Goldman using a student t-test. Regarding biomechanical parameters, there were differences in the applanation length 2 (A-L2), in the applanation velocity 2 (A-V2) and in the PD. By sex, only the applanation length 1 (A-L1) was found to be different in control group. A positive and significant Pearson correlation was found between CDR and the A-L1. CONCLUSION Corneal biomechanical properties have shown differences between CG and healthy subjects and also between men and women.
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Affiliation(s)
- Sara Garcia Caride
- Ophthalmology, Clinico San Carlos Hospital, Profesor Martín Lagos Street, Madrid, ES 28040, Spain
| | - Lucia Perucho González
- Ophthalmology, Clinico San Carlos Hospital, Profesor Martín Lagos Street, Madrid, ES 28040, Spain
| | - Federico Sáenz Francés
- Ophthalmology, Clinico San Carlos Hospital, Profesor Martín Lagos Street, Madrid, ES 28040, Spain
| | - Julián García Feijoo
- Ophthalmology, Clinico San Carlos Hospital, Profesor Martín Lagos Street, Madrid, ES 28040, Spain
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Sun Y, Guo Y, Cao K, Zhang Y, Xie Y, Pang R, Shi Y, Wang H, Wang N. Relationship between corneal stiffness parameters and lamina cribrosa curvature in normal tension glaucoma. Eur J Ophthalmol 2020; 31:3049-3056. [PMID: 33334173 DOI: 10.1177/1120672120982521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To evaluate the relationship between corneal biomechanical parameters and lamina cribrosa (LC) curvature in normal tension glaucoma (NTG). METHODS 95 eyes of 56 NTG patients were enrolled in this prospective, observational study. Corneal biomechanical parameters, including stiffness parameters at applanation 1 (SP-A1), deformation amplitude ratio (DA ratio), inverse concave radius and biomechanically corrected intraocular pressure estimate (bIOP), were captured using the Corneal Visualization Scheimpflug Technology instrument (Corvis-ST). LC curvature was evaluated by mean adjusted LC curvature index (maLCCI) averaged by the measurements on 12 radial B-scan images obtained using swept-source optical coherence tomography (SS-OCT). Linear mixed models were constructed to assess the relationship between corneal biomechanical parameters and LC curvature. RESULTS The mean age of participants was 51.04 ± 13.74 years (range, 24-82 years). The SP-A1 and maLCCI were 93.50 ± 13.82 mm Hg/mm and 7.57 ± 1.58, respectively. In univariate and multivariate analysis, SP-A1 (p < 0.001 and p = 0.001) and age (p = 0.010 and p = 0.024) were both significantly associated with maLCCI. The LC curvature increased with softer cornea demonstrated by lower SP-A1 and younger eyes. There was no statistical significance interaction between SP-A1 and age (p = 0.194). CONCLUSIONS The greater posterior LC curvature was associated with lower corneal stiffness parameters and younger eyes in NTG patients. CLINICAL TRIAL REGISTRATION Chinese Clinical Trial Registry, ChiCTR1900021465.
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Affiliation(s)
- Yunxiao Sun
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
| | - Yiqin Guo
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
| | - Kai Cao
- Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
| | - Yue Zhang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
| | - Yuan Xie
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ruiqi Pang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
| | - Yan Shi
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Huaizhou Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ningli Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
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50
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Korneva A, Kimball EC, Jefferys JL, Quigley HA, Nguyen TD. Biomechanics of the optic nerve head and peripapillary sclera in a mouse model of glaucoma. J R Soc Interface 2020; 17:20200708. [PMID: 33323053 PMCID: PMC7811579 DOI: 10.1098/rsif.2020.0708] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/17/2020] [Indexed: 01/09/2023] Open
Abstract
The deformation of the mouse astrocytic lamina (AL) and adjacent peripapillary sclera (PPS) was measured in response to elevated intraocular pressure. We subjected explanted mouse eyes to inflation testing, comparing control eyes to those 3 days and 6 weeks after induction of ocular hypertension (OHT) via ocular microbead injection. Laser scanning microscopy was used with second harmonic generation to image the collagenous PPS and two-photon fluorescence to image transgenic fluorescent astrocytes in the AL. Digital volume correlation was applied to calculate strains in the PPS and AL. The specimen-averaged strains were biaxial in the AL and PPS, with greater strain overall in the x- than y-direction in the AL and greater strain in the θ- than the r-direction in the PPS. Strains increased after 3-day OHT, with greater strain overall in the 3-day AL than control AL, and greater circumferential strain in the 3-day PPS than control PPS. In the 6-week OHT eyes, AL and PPS strains were similar overall to controls. This experimental glaucoma model demonstrated a dynamic change in the mechanical behaviour of the AL and PPS over time at the site of neuronal injury and remodelling in glaucoma.
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Affiliation(s)
- Arina Korneva
- Glaucoma Center of Excellence, Wilmer Eye Institute, John Hopkins University, Baltimore, MD, USA
| | - Elizabeth C. Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, John Hopkins University, Baltimore, MD, USA
| | - Joan L. Jefferys
- Glaucoma Center of Excellence, Wilmer Eye Institute, John Hopkins University, Baltimore, MD, USA
| | - Harry A. Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, John Hopkins University, Baltimore, MD, USA
| | - Thao D. Nguyen
- Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Ophthalmology, The Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Materials Science, The Johns Hopkins University, Baltimore, MD 21218, USA
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