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Aung MH, Aleman TS, Garcia AS, McGeehan B, Ying GS, Avery RA. Stimulus type and duration affect magnitude and evolution of flicker-induced hyperemia measured by laser speckle flowgraphy at the optic disc and peripapillary vessels. Sci Rep 2024; 14:6659. [PMID: 38509194 PMCID: PMC10954713 DOI: 10.1038/s41598-024-57263-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 03/15/2024] [Indexed: 03/22/2024] Open
Abstract
Neurovascular coupling is a vital mechanism employed by the cerebrovascular system, including the eye, to regulate blood flow in periods of neuronal activation. This study aims to investigate if laser speckle flowgraphy (LSFG) can detect coupling response elicited by flickering light stimuli and how variations in stimulus type and duration can affect the magnitude and evolution of blood flow in the optic nerve head (ONH) and peripapillary vessels. Healthy adults were exposed to two types of 10-Hz flicker stimuli: a photopic negative response-like stimulus (PhNR-S) or a visual evoked potential-like stimulus (VEP-S)-each presented in separate 10- and 60-s epochs. Both PhNR-S and VEP-S significantly increased ONH blood flow (p < 0.001) immediately after flicker cessation, with a trend of 60-s stimuli (PhNR-S = 11.6%; VEP-S = 10.4%) producing a larger response than 10-s stimuli (PhNR-S = 7.5%; VEP-S = 6.2%). Moreover, exposure to 60-s stimuli elicited a significantly prolonged ONH hyperemic response, especially with PhNR-S. Lastly, stimulation with either 60-s stimuli elicited a robust increase in blood flow within the peripapillary arterioles (p < 0.01) and venules (p < 0.01) as well. Flicker stimulation with common visual electrophysiology stimuli (PhNR-S and VEP-S) induced a demonstrable increase in ONH and peripapillary vessel blood flow, which varied with flicker duration. Our results validate that LSFG is a robust method to quantify flicker-induced hyperemic responses and to study neurovascular coupling in humans.
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Affiliation(s)
- Moe H Aung
- Departments of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
- Department of Ophthalmology, Dell Medical School at The University of Texas at Austin, Austin, TX, USA.
| | - Tomas S Aleman
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Arielle S Garcia
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Brendan McGeehan
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Gui-Shuang Ying
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Robert A Avery
- Departments of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Department of Ophthalmology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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2
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Liu B, Postnov D, Boas DA, Cheng X. Dynamic light scattering and laser speckle contrast imaging of the brain: theory of the spatial and temporal statistics of speckle pattern evolution. BIOMEDICAL OPTICS EXPRESS 2024; 15:579-593. [PMID: 38404305 PMCID: PMC10890898 DOI: 10.1364/boe.510333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/13/2023] [Accepted: 12/20/2023] [Indexed: 02/27/2024]
Abstract
Dynamic light scattering (DLS) and laser speckle contrast imaging (LSCI) are closely related techniques that exploit the statistics of speckle patterns, which can be utilized to measure cerebral blood flow (CBF). Conventionally, the temporal speckle intensity auto-correlation function g 2 t ( τ ) is calculated in DLS, while the spatial speckle contrast Ks is calculated in LSCI measurements. Due to the rapid development of CMOS detection technology with increased camera frame rates while still maintaining a large number of pixels, the ensemble or spatial average of g 2 s ( τ ) as well as the temporal contrast Kt can be easily calculated and utilized to quantify CBF. Although many models have been established, a proper summary is still lacking to fully characterize DLS and LSCI measurements for spatial and temporal statistics, laser coherence properties, various motion types, etc. As a result, there are many instances where theoretical models are misused. For instance, mathematical formulas derived in the diffusive regime or for ergodic systems are sometimes applied to small animal brain measurements, e.g., mice brains, where the assumptions are not valid. Therefore, we aim to provide a review of the speckle theory for both DLS and LSCI measurements with detailed derivations from first principles, taking into account non-ergodicity, spatial and temporal statistics of speckles, scatterer motion types, and laser coherence properties. From these calculations, we elaborate on the differences between spatial and temporal averaging for DLS and LSCI measurements that are typically ignored but can result in inaccurate measurements of blood flow, particularly the spatially varying nature of the static component in g 2 t ( τ ) and Kt. We also obtained g 2 s ( τ ) maps in in vivo mouse brain measurements using high frame rate CMOS cameras which have not been demonstrated before, and compared with g 2 t ( τ ) and Ks,t. This work provides a useful guide for choosing the correct model to analyze spatial and temporal speckle statistics in in-vivo DLS and LSCI measurements.
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Affiliation(s)
- Bingxue Liu
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Dmitry Postnov
- Aarhus University, CFIN Department of Clinical Medicine, Aarhus, 1710, Denmark
| | - David A. Boas
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Xiaojun Cheng
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
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3
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González Olmos A, Zilpelwar S, Sunil S, Boas DA, Postnov DD. Optimizing the precision of laser speckle contrast imaging. Sci Rep 2023; 13:17970. [PMID: 37864006 PMCID: PMC10589309 DOI: 10.1038/s41598-023-45303-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/18/2023] [Indexed: 10/22/2023] Open
Abstract
Laser speckle contrast imaging (LSCI) is a rapidly developing technology broadly applied for the full-field characterization of tissue perfusion. Over the recent years, significant advancements have been made in interpreting LSCI measurements and improving the technique's accuracy. On the other hand, the method's precision has yet to be studied in detail, despite being as important as accuracy for many biomedical applications. Here we combine simulation, theory and animal experiments to systematically evaluate and re-analyze the role of key factors defining LSCI precision-speckle-to-pixel size ratio, polarisation, exposure time and camera-related noise. We show that contrary to the established assumptions, smaller speckle size and shorter exposure time can improve the precision, while the camera choice is less critical and does not affect the signal-to-noise ratio significantly.
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Affiliation(s)
| | - Sharvari Zilpelwar
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Smrithi Sunil
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - David A Boas
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Dmitry D Postnov
- Department of Clinical Medicine, Aarhus University, 8200, Aarhus, Denmark.
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Andrade DDM, Oliveira JBV, Lacordia MHFA, Laterza MC, Martinez DG. Low Ocular Perfusion Pressure Values at Rest and during Resistance Exercise in Offspring of Glaucoma Patients. J Curr Ophthalmol 2023; 35:320-325. [PMID: 39281407 PMCID: PMC11392303 DOI: 10.4103/joco.joco_207_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/24/2023] [Accepted: 11/25/2023] [Indexed: 09/18/2024] Open
Abstract
Purpose To compare the ocular perfusion pressure (OPP) response during physical exercise in individuals with and without a family history (FH+, FH-) of glaucoma. Methods Thirty-four subjects, divided into FH+ and FH- groups, realized 3 min at rest, 3 min of isometric handgrip exercise at 30% of maximal voluntary contraction, followed by 3 min of recovery. Blood pressure (Dixtal® automatic device) and intraocular pressure (Goldmann applanation tonometer) were measured during rest, exercise, and recovery. The mean OPP (mOPP) was calculated. Results In the FH+ group (17 subjects), baseline mOPP values were significantly lower than in the FH- group (17 subjects) (right eye: P < 0.001, left eye: P < 0.001, respectively). During exercise, both the FH+ and FH- groups showed a similar increase in mOPP in both eyes (right eye: FH+: 38 ± 4 mmHg vs. 51 ± 7 mmHg, FH-: 48 ± 5 mmHg vs. 57 ± 9 mmHg, P < 0.001; left eye: FH+: 39 ± 3 mmHg vs. 51 ± 7 mmHg; FH-: 46 ± 5 mmHg vs. 58 ± 8 mmHg, P < 0.001, respectively). However, the FH+ group maintained significantly lower mOPP values compared to the FH- group in the right and left eyes (group effect: P = 0.002, P = 0.002, respectively). The percentage of increase in mOPP in the FH+ group was greater compared to the FH- group during exercise (right eye: 34.1% ± 15.9% vs. 22.1% ± 13.2%, respectively; P = 0.025; left eye: 33.2% ± 17.7% vs. 22.4% ± 13.7%, respectively, P = 0.056). Conclusions mOPP increased during physical exercise in both groups, but the FH+ group had lower absolute values. In addition, the FH+ group appears to demonstrate a higher percentage increase in mOPP compared to the FH- group.
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Affiliation(s)
- Diana de Medeiros Andrade
- Cardiovascular Research Unit and Exercise Physiology, Federal University of Juiz de Fora, Minas Gerais, Brazil
| | | | | | - Mateus Camaroti Laterza
- Cardiovascular Research Unit and Exercise Physiology, Federal University of Juiz de Fora, Minas Gerais, Brazil
| | - Daniel Godoy Martinez
- Cardiovascular Research Unit and Exercise Physiology, Federal University of Juiz de Fora, Minas Gerais, Brazil
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Liu B, Shah S, Küreli G, Devor A, Boas DA, Cheng X. Measurements of slow tissue dynamics with short-separation speckle contrast optical spectroscopy. BIOMEDICAL OPTICS EXPRESS 2023; 14:4790-4799. [PMID: 37791271 PMCID: PMC10545176 DOI: 10.1364/boe.497604] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 10/05/2023]
Abstract
Laser speckle contrast imaging (LSCI) measures 2D maps of cerebral blood flow (CBF) in small animal brains such as mice. The contrast measured in LSCI also includes the static and slow-varying components that contain information about brain tissue dynamics. But these components are less studied as compared to the fast dynamics of CBF. In traditional wide-field LSCI, the contrast measured in the tissue is largely contaminated by neighboring blood vessels, which reduces the sensitivity to these static and slow components. Our goal is to enhance the sensitivity of the contrast to static and slow tissue dynamics and test models to quantify the characteristics of these components. To achieve this, we have developed a short-separation speckle contrast optical spectroscopy (ss-SCOS) system by implementing point illumination and point detection using multi-mode fiber arrays to enhance the static and slow components in speckle contrast measurements as compared to traditional wide-field LSCI (WF-LSCI). We observed larger fractions of the static and slow components when measured in the tissue using ss-SCOS than in traditional LSCI for the same animal and region of interest. We have also established models to obtain the fractions of the static and slow components and quantify the decorrelation time constants of the intensity auto-correlation function for both fast blood flow and slower tissue dynamics. Using ss-SCOS, we demonstrate the variations of fast and slow brain dynamics in animals before and post-stroke, as well as within an hour post-euthanasia. This technique establishes the foundation to measure brain tissue dynamics other than CBF, such as intracellular motility.
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Affiliation(s)
- Bingxue Liu
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Shashwat Shah
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Gülce Küreli
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
| | - Anna Devor
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - David A. Boas
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Xiaojun Cheng
- Neurophotonics Center, Boston University, Boston, Massachusetts 02215, USA
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA
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Bajka A, Foa N, Sidhu S, Rejdak M, Said S, Wiest MRJ, Hamann T, Blaser F, Zweifel SA. Analysis of Blood Flow in the Macula and Optic Nerve Head in Healthy Young Volunteers Using Laser Speckle Flowgraphy. Klin Monbl Augenheilkd 2023; 240:608-612. [PMID: 37164413 DOI: 10.1055/a-2026-0924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
PURPOSE To assess optic nerve head (ONH) and macular blood flow in young healthy volunteers using laser speckle flowgraphy (LSFG). METHODS This is a prospective single-center study conducted at the Department of Ophthalmology, University Hospital Zurich from May to November 2021. Young, healthy men aged ≥ 18 years without ocular or systemic diseases were included. A corrected visual acuity (VA) of 0.0 logMAR or better in both eyes and an intraocular pressure (IOP) of 21 mmHg or lower were required for inclusion. Subjects exceeding a spherical equivalent (SE) of ± 6 diopters (dpt) were excluded. Blood flow in the macula and the ONH was recorded using the Nidek LSFG RetFlow device (Nidek Company, Ltd., Hirioshi-cho, Japan). Laser power was set to 0.5 Millivolts (mV). Mean blur rate (MBR) was recorded as a parameter for blood flow. MBR is a calculated parameter that represents relative blood flow velocity correlated with the real anatomical blood flow rate. Colored heat maps of the recorded retinal area were generated automatically by the RetFlow device. RESULTS Final analyses included 83 eyes of 43 male volunteers. Mean age was 21.9 years (SD ± 1.5, range: 20 to 29). Mean corrected VA was - 0.1 logMAR (SD ± 0.05, range: - 0.2 to 0.0), mean IOP was 15.4 mmHg (SD ± 2.5, range: 8.5 to 18.5), and mean SE was - 0.3 dpt (SD ± 1.2, range: - 5.0 to 1.2). Mean ONH MBR was 37.44 (SD ± 7.9, range: 22.5 to 53.5) and mean macular MBR was 27.8 (SD ± 9.7, range: 6.4 to 57.7). Pearson's Test showed a strong correlation between macular and papillary blood flow (p < 0.05, coefficient: 0.647). CONCLUSION This study provides both ONH and macular blood flow data in a healthy young male population, showing a strong correlation between ONH and macular blood flow in the examined eyes. Further investigations are required to assess the validity of MBR as a parameter for the combined evaluation of retinal blood flow at the macula and ONH in healthy volunteers and patients with various diseases.
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Affiliation(s)
- Anahita Bajka
- Department of Ophthalmology, University Hospital of Zurich, University of Zurich, Switzerland
| | - Nastasia Foa
- Department of Ophthalmology, University Hospital of Zurich, University of Zurich, Switzerland
| | - Sophia Sidhu
- Faculty of Medicine, University of San Diego, San Diego, California, United States
| | - Magdalena Rejdak
- Department of Ophthalmology, University Hospital of Zurich, University of Zurich, Switzerland
| | - Sadiq Said
- Department of Ophthalmology, University Hospital of Zurich, University of Zurich, Switzerland
| | | | - Timothy Hamann
- Department of Ophthalmology, University Hospital of Zurich, University of Zurich, Switzerland
| | - Frank Blaser
- Department of Ophthalmology, University Hospital of Zurich, University of Zurich, Switzerland
| | - Sandrine Anne Zweifel
- Department of Ophthalmology, University Hospital of Zurich, University of Zurich, Switzerland
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7
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Sampietro T, Pino BD, Bigazzi F, Sbrana F, Ripoli A, Fontanelli E, Pianelli M, Luciani R, Lepri A, Calzetti G. Acute Increase in Ocular Microcirculation Blood Flow Upon Cholesterol Removal. The Eyes Are the Window of the Heart. Am J Med 2023; 136:108-114. [PMID: 36152804 DOI: 10.1016/j.amjmed.2022.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 03/08/2022] [Accepted: 08/06/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND Lipoprotein apheresis acutely increases coronary microvascular blood flow. However, measurement techniques are time-consuming, costly, and invasive. The ocular vasculature may be an appropriate surrogate and an easily accessible window to investigate the microcirculation. Recent advances in ocular imaging techniques enable quick, noninvasive quantification of ocular microcirculation blood flow. The insights from these techniques represent a significant opportunity to study the short-term changes in optic disk blood flow after lipoprotein apheresis for inherited hypercholesterolemia. METHODS This study was performed at the Italian Reference Center for Inherited Dyslipidemias in Tuscany. The study sample was comprised of 22 patients with inherited hypercholesterolemia who were previously studied for coronary microcirculation. Laser speckle flowgraphy (LSFG) was used to measure optic disk blood flow before and after lipoprotein apheresis. The main outcomes measures were average tissue blood flow (referred to as mean tissue) and arteriolar/venular average blood flow (referred to as mean vessel). Eyes were divided into 2 groups based on pre-lipoprotein apheresis optic disk blood flow values. P < .05 was considered statistically significant. RESULTS After each lipoprotein apheresis treatment resulting in the reduction of plasma lipids, there was a concurrent increase in all optic disk microcirculatory parameters. The increase was statistically significant in eyes with lower pre-apheresis optic disk blood flow values (mean tissue +7.0%, P < .005; mean vessel +7.2%, P < .05). CONCLUSIONS A single lipoprotein apheresis session resulted in a statistically significant short-term increase in optic disk blood flow. These findings together with previous coronary microcirculation data suggest a similar ocular and coronary blood flow response to lipoprotein apheresis. Ocular microcirculation may represent a versatile biomarker for evaluating systemic microcirculatory health, including coronary microcirculation. Hence, it is plausible that plasma lipoprotein levels may influence optic disk blood flow.
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Affiliation(s)
- Tiziana Sampietro
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa Italy.
| | - Beatrice Dal Pino
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa Italy
| | - Federico Bigazzi
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa Italy
| | - Francesco Sbrana
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa Italy
| | - Andrea Ripoli
- Bioengineering Department, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | | | - Mascia Pianelli
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa Italy
| | - Roberta Luciani
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa Italy
| | - Antonio Lepri
- Institute of Ophthalmology, University of Pisa, Italy
| | - Giacomo Calzetti
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Ophthalmology Unit, University Hospital of Parma, Parma, Italy
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Feng X, Jin Z, Zhou Z, Gao M, Jiang C, Hu Y, Lu Y, Li J, Ren Q, Zhou C. Retinal oxygen kinetics imaging and analysis (ROKIA) based on the integration and fusion of structural-functional imaging. BIOMEDICAL OPTICS EXPRESS 2022; 13:5400-5417. [PMID: 36425629 PMCID: PMC9664891 DOI: 10.1364/boe.465991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/27/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
The retina is one of the most metabolically active tissues in the body. The dysfunction of oxygen kinetics in the retina is closely related to the disease and has important clinical value. Dynamic imaging and comprehensive analyses of oxygen kinetics in the retina depend on the fusion of structural and functional imaging and high spatiotemporal resolution. But it's currently not clinically available, particularly via a single imaging device. Therefore, this work aims to develop a retinal oxygen kinetics imaging and analysis (ROKIA) technology by integrating dual-wavelength imaging with laser speckle contrast imaging modalities, which achieves structural and functional analysis with high spatial resolution and dynamic measurement, taking both external and lumen vessel diameters into account. The ROKIA systematically evaluated eight vascular metrics, four blood flow metrics, and fifteen oxygenation metrics. The single device scheme overcomes the incompatibility of optical design, harmonizes the field of view and resolution of different modalities, and reduces the difficulty of registration and image processing algorithms. More importantly, many of the metrics (such as oxygen delivery, oxygen metabolism, vessel wall thickness, etc.) derived from the fusion of structural and functional information, are unique to ROKIA. The oxygen kinetic analysis technology proposed in this paper, to our knowledge, is the first demonstration of the vascular metrics, blood flow metrics, and oxygenation metrics via a single system, which will potentially become a powerful tool for disease diagnosis and clinical research.
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Affiliation(s)
- Ximeng Feng
- Department of Biomedical Engineering,
College of Future Technology, Peking
University, Beijing 100871, China
- Institute of Biomedical
Engineering, Shenzhen Bay Laboratory, Shenzhen 5181071,
China
- Institute of Biomedical
Engineering, Peking University Shenzhen Graduate School,
Shenzhen 518055, China
- Institute of Medical
Technology, Peking University Health Science Center, Peking
University, Beijing 100191, China
| | - Zi Jin
- Institute of Biomedical
Engineering, Shenzhen Bay Laboratory, Shenzhen 5181071,
China
- Institute of Biomedical
Engineering, Peking University Shenzhen Graduate School,
Shenzhen 518055, China
| | - Zixia Zhou
- Department of Ophthalmology,
Peking University Shenzhen Hospital,
Shenzhen 518034, China
| | - Mengdi Gao
- Department of Biomedical Engineering,
College of Future Technology, Peking
University, Beijing 100871, China
- Institute of Biomedical
Engineering, Shenzhen Bay Laboratory, Shenzhen 5181071,
China
- Institute of Biomedical
Engineering, Peking University Shenzhen Graduate School,
Shenzhen 518055, China
- Institute of Medical
Technology, Peking University Health Science Center, Peking
University, Beijing 100191, China
| | - Chunxia Jiang
- Department of Ophthalmology,
Peking University Shenzhen Hospital,
Shenzhen 518034, China
| | - Yicheng Hu
- Department of Biomedical Engineering,
College of Future Technology, Peking
University, Beijing 100871, China
- Institute of Biomedical
Engineering, Shenzhen Bay Laboratory, Shenzhen 5181071,
China
- Institute of Biomedical
Engineering, Peking University Shenzhen Graduate School,
Shenzhen 518055, China
- Institute of Medical
Technology, Peking University Health Science Center, Peking
University, Beijing 100191, China
| | - Yanye Lu
- Institute of Biomedical
Engineering, Peking University Shenzhen Graduate School,
Shenzhen 518055, China
- Institute of Medical
Technology, Peking University Health Science Center, Peking
University, Beijing 100191, China
| | - Jinying Li
- Department of Ophthalmology,
Peking University Shenzhen Hospital,
Shenzhen 518034, China
| | - Qiushi Ren
- Department of Biomedical Engineering,
College of Future Technology, Peking
University, Beijing 100871, China
- Institute of Biomedical
Engineering, Shenzhen Bay Laboratory, Shenzhen 5181071,
China
- Institute of Biomedical
Engineering, Peking University Shenzhen Graduate School,
Shenzhen 518055, China
- Institute of Medical
Technology, Peking University Health Science Center, Peking
University, Beijing 100191, China
| | - Chuanqing Zhou
- College of Medical Instrument, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China
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9
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Waveform changes of laser speckle flowgraphy in the temporal optic nerve head and peripapillary atrophy after trabeculectomy in open-angle glaucoma. Sci Rep 2022; 12:9802. [PMID: 35697840 PMCID: PMC9192707 DOI: 10.1038/s41598-022-13989-2] [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] [Received: 04/05/2022] [Accepted: 05/31/2022] [Indexed: 11/17/2022] Open
Abstract
A prospective study was conducted on 33 eyes of 33 patients with open-angle glaucoma who underwent trabeculectomy to investigate hemodynamic changes in the temporal optic nerve head (ONH) and peripapillary atrophy (PPA) after trabeculectomy. Laser speckle flowgraphy of ONH and PPA was performed at baseline and at 1, 3, and 6 months postoperatively. The waveforms of the mean blur rate in the tissue area (MT) in the temporal ONH, βPPA (with Bruch’s membrane), and γPPA (without Bruch’s membrane) were evaluated. Mean intra-ocular pressure (IOP) decreased from 19.1 ± 0.8 to 8.5–9.6 ± 0.7 mmHg at postoperative visits. The average MT in the βPPA region increased significantly at all postoperative time points, whereas those in the ONH and γPPA regions remained unchanged. The blowout score (BOS) increased significantly, and the resistivity index decreased significantly at all time points in all regions, which was associated with decreased IOP. The current study showed two novel findings: MT increased after trabeculectomy only in βPPA, where the choroid was present. IOP decrease-associated BOS increase occurred postoperatively in all regions, which indicates that IOP reduction may decrease vascular transmural pressure and contribute to stable blood flow uniformly, despite structural differences between the regions.
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10
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Lu Y, Zhou H, Zhou X, Chen Y, Wang RK. Correlation Between Laser Speckle Flowgraphy and OCT-Derived Retinal and Choroidal Metrics in Healthy Human Eye. Transl Vis Sci Technol 2022; 11:15. [PMID: 35704328 PMCID: PMC9206497 DOI: 10.1167/tvst.11.6.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 05/17/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose To investigate the correlation between laser speckle flowgraphy (LSFG) signals and the quantitative metrics derived from optical coherence tomography (OCT) in normal eyes. Methods LSFG, OCT, and OCT angiography (OCTA) imaging were performed on normal participants using a custom-designed LSFG system and a commercial swept-source OCT system. Mean (PWM) and amplitude (PWA) of the LSFG pulse waveform were selected to quantify the LSFG signals. Retinal and choroidal maps were obtained using the standard 6 × 6 mm OCT and OCTA scans. Structural and vascular metrics maps, including thickness, vessel area density, vessel skeleton density, and vessel diameter index of the retina, and choroidal thickness (CT), choroidal vessel volume (CVV) and choroidal vessel index (CVI), were employed to quantify the retinal and choroidal properties. Correlation analysis was then performed between the LSFG, retinal, and choroidal metrics maps. Results Twelve healthy participants aged 23 to 36 years were enrolled in this study. The spatial distribution of the PWM and PWA values was highly correlated with that of the CT and CVV metrics. On average, Spearman correlation coefficients (ρ) were 0.80 and 0.78 (all P < 0.001) for the correlations between PWM and CT and CVV, respectively, and were 0.61 and 0.63 (all P < 0.05) for the correlations between PWA and CT and CVV, respectively. In comparison, both PWM and PWA were generally weak or not correlated with all the retinal metrics and CVI. Conclusions LSFG signals were positively correlated with the choroidal thickness and vessel volume, suggesting choroidal blood flows dominate the LSFG signals at the area absent of large retinal vessels. Translational Relevance This study illustrates the dominant source of the LSFG signals in the eye.
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Affiliation(s)
- Yiming Lu
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Xiao Zhou
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Yuxuan Chen
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Karalis Johnson Retina Center, Department of Ophthalmology, University of Washington, Seattle, WA, USA
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11
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Calzetti G, Mursch‐Edlmayr AS, Bata AM, Ungaro N, Mora P, Chua J, Schmidl D, Bolz M, Garhöfer G, Gandolfi S, Schmetterer L, Wong D. Measuring optic nerve head perfusion to monitor glaucoma: a study on structure-function relationships using laser speckle flowgraphy. Acta Ophthalmol 2022; 100:e181-e191. [PMID: 33880888 DOI: 10.1111/aos.14862] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 02/21/2021] [Accepted: 03/16/2021] [Indexed: 12/31/2022]
Abstract
PURPOSE We aimed to describe the global and localized correlations among visual field (VF) sensitivity, optic nerve head (ONH) perfusion measured by laser speckle flowgraphy (LSFG) and neural structure measured by optical coherence tomography (OCT) in open-angle glaucoma (OAG) and to compare the floor effect for LSFG and OCT. METHODS Cross-sectional, multicenter study including one eye each from fifty OAG patients (mean age 69.3 years; average VF mean deviation, MD, -8.5 dB, range -25.17 to 0.85 dB) and fifty-one controls. Patients underwent SITA standard 24-2 automated perimetry and measurement of ONH perfusion, peripapillary retinal nerve fibre layer thickness (RNFLT) and macular ganglion cell-inner plexiform layer thickness (GCIPLT). We tested the presence of a significant change (breakpoint) in the correlation slope with VF sensitivity to assess floor effect. RESULTS The correlation between the LSFG parameter Mean All (MA) of the global disc area and MD (r = 0.56, p < 0.001) did not show a breakpoint, in contrast to the correlations between MD and OCT global parameters, which showed breakpoints at -8.53 and -4.05 dB for RNFLT and GCIPLT, respectively. Global and localized correlations with VF sensitivity were stronger for LSFG compared to OCT. In particular, LSFG outperformed OCT in the correlation with the central VF sector (r = 0.50, p < 0.001 and r = 0.06, p = 0.67 for MA and RNFLT, respectively). CONCLUSION The global and sectoral correlations with VF sensitivity and the favourable floor effect compared to OCT indicate LSFG as a promising tool to monitor progression particularly in late-stage glaucoma. Further longitudinal studies are warranted.
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Affiliation(s)
- Giacomo Calzetti
- Department of Ophthalmology University Hospital of Parma Parma Italy
- Institute of Molecular and Clinical Ophthalmology Basel Basel Switzerland
| | | | - Ahmed M. Bata
- Department of Clinical Pharmacology Medical University of Vienna Vienna Austria
- Vienna Health Association Kaiser Franz Josef (Favoriten) Hospital Vienna Austria
| | - Nicola Ungaro
- Department of Ophthalmology University Hospital of Parma Parma Italy
| | - Paolo Mora
- Department of Ophthalmology University Hospital of Parma Parma Italy
| | - Jacqueline Chua
- Singapore Eye Research Institute Singapore National Eye Centre Singapore Singapore
- Academic Clinical Program Duke‐NUS Medical School Singapore Singapore
| | - Doreen Schmidl
- Department of Clinical Pharmacology Medical University of Vienna Vienna Austria
| | - Matthias Bolz
- Department of Ophthalmology Kepler University Clinic Johannes Kepler University Linz Austria
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology Medical University of Vienna Vienna Austria
| | - Stefano Gandolfi
- Department of Ophthalmology University Hospital of Parma Parma Italy
| | - Leopold Schmetterer
- Institute of Molecular and Clinical Ophthalmology Basel Basel Switzerland
- Department of Clinical Pharmacology Medical University of Vienna Vienna Austria
- Singapore Eye Research Institute Singapore National Eye Centre Singapore Singapore
- Academic Clinical Program Duke‐NUS Medical School Singapore Singapore
- School of Chemical and Biomedical Engineering Nanyang Technological University Singapore Singapore
| | - Damon Wong
- Singapore Eye Research Institute Singapore National Eye Centre Singapore Singapore
- SERI‐NTU Advanced Ocular Engineering (STANCE) Singapore Singapore
- NTU Institute of Health Technologies Singapore Singapore
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12
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Samaha D, Diaconu V, Bouchard JF, Desalliers C, Dupont A. Effect of Latanoprostene Bunod on Optic Nerve Head Blood Flow. Optom Vis Sci 2022; 99:172-176. [PMID: 34889858 DOI: 10.1097/opx.0000000000001842] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SIGNIFICANCE Topical latanoprostene bunod increases capillary oxygen saturation and blood volume at the optic nerve head in healthy individuals. PURPOSE This study aimed to evaluate the effect of topical latanoprostene bunod on optic nerve blood volume and oxygen saturation in a population of healthy participants. METHODS In this prospective double-blind crossover study, 23 healthy participants aged from 21 to 62 years were recruited. Optic nerve head capillary blood volume (ONHvol) and oxygen saturation (ONHSaO2) baselines were measured over a period of 2 hours using multichannel spectroscopic reflectometry and were remeasured after a 7-day once-daily instillation regimen of either latanoprost 0.005% or latanoprostene bunod 0.024%. After a 30-day washout period, participants were crossed over to the alternate product, and measurements were repeated. Participants were used as their own baselines to calculate variation in ONHvol and ONHSaO2 across time and pharmacological agents. The Friedman test was used to establish significant differences in optic nerve head parameters from baseline values, and Conover post hoc analysis was carried for multiple between-group comparisons. RESULTS Latanoprostene bunod 0.024% induced a significant increase of 4% in ONHSaO2 compared with latanoprost 0.005% (P < .001). Furthermore, latanoprostene bunod increased ONHvol levels by more than twofold at all time points (P < .001 at T60, T90, and T120). The increase in ONHvol was 66.2% higher than levels achieved with latanoprost at T60 (P = .001), 47% higher at T90 (P < .001), and 45% higher at T120 (P < .01). CONCLUSIONS Latanoprostene bunod 0.024% induces a significant increase in optic nerve head blood volume and oxygen saturation in healthy subjects, when compared with latanoprost 0.005%. Future studies are needed to evaluate whether similar responses are elicited in patients suffering from glaucomatous optic neuropathy.
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Affiliation(s)
| | - Vasile Diaconu
- Montreal University School of Optometry, Montreal, Quebec, Canada
| | | | | | - Ariane Dupont
- Montreal University School of Optometry, Montreal, Quebec, Canada
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13
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Calzetti G, La Morgia C, Cattaneo M, Carta A, Bosello F, Amore G, Carbonelli M, Cascavilla ML, Gandolfi S, Carelli V, Schmetterer L, Scholl HPN, Barboni P. Longitudinal Study of Optic Disk Perfusion and Retinal Structure in Leber's Hereditary Optic Neuropathy. Invest Ophthalmol Vis Sci 2022; 63:43. [PMID: 35098304 PMCID: PMC8802032 DOI: 10.1167/iovs.63.1.43] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Purpose The purpose of this study was to evaluate optic disk perfusion and neural retinal structure in patients with subacute Leber's hereditary optic neuropathy (LHON) and LHON carriers, as compared with healthy controls. Methods This study included 8 patients with LHON in the subacute stage, 10 asymptomatic carriers of a LHON-associated mitochondrial DNA mutation, and 40 controls. All subjects underwent measurement of the retinal nerve fiber layer (RNFL) thickness, the ganglion cell-inner plexiform layer (GCIPL) thickness using optical coherence tomography and optic disk microvascular perfusion (Mean Tissue [MT]) using laser speckle flowgraphy (LSFG). Patients were re-examined after a median interval of 3 months from the baseline visit. Results LHON carriers had higher values of RNFL thickness, GCIPL thickness, and disk area than controls (P < 0.05), whereas MT was not different between the two groups (P = 0.936). Median MT and RNFL thickness were 32% and 15% higher in the early subacute stage of the disease than in controls (P < 0.001 and P = 0.001). MT declined below the values of controls during the late subacute stage (P = 0.024), whereas RNFL thickness declined later during the dynamic stage (P < 0.001). GCIPL thickness was lower in patients with LHON than in controls independently of the stage of the disease (P < 0.001). Conclusions The high blood flow at the optic disk during the early subacute stage may be the consequence of vasodilation due to nitric oxide release as compensation to mitochondrial impairment. Optic disk perfusion as measured by LSFG is a promising biomarker for LHON diagnosis and monitoring as well as an objective outcome measure for assessing response to therapies.
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Affiliation(s)
- Giacomo Calzetti
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.,Department of Ophthalmology, University of Basel, Basel, Switzerland.,Department of Ophthalmology, University Hospital of Parma, Parma, Italy
| | - Chiara La Morgia
- IRCCS, Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, Bologna, Italy
| | - Marco Cattaneo
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.,Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Arturo Carta
- Department of Ophthalmology, University Hospital of Parma, Parma, Italy
| | - Francesca Bosello
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, Ocular Immunology and Neuroophthalmology Service, AOUI-University of Verona, Verona, Italy
| | - Giulia Amore
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Michele Carbonelli
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Maria Lucia Cascavilla
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Stefano Gandolfi
- Department of Ophthalmology, University Hospital of Parma, Parma, Italy
| | - Valerio Carelli
- IRCCS, Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Leopold Schmetterer
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.,Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Piero Barboni
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy.,Studio Oculistico d'Azeglio, Bologna, Italy
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14
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Short-term changes in retinal and choroidal relative flow volume after anti-VEGF treatment for neovascular age-related macular degeneration. Sci Rep 2021; 11:23723. [PMID: 34887454 PMCID: PMC8660908 DOI: 10.1038/s41598-021-03179-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 10/25/2021] [Indexed: 11/29/2022] Open
Abstract
The effects of anti-vascular endothelial growth factor (anti-VEGF) agents on the native ocular vasculature are poorly understood. This pilot study aimed to assess short-term changes in retinal and choroidal perfusion after anti-VEGF treatment for neovascular exudative age-related macular degeneration (nAMD) using the relative flow volume (RFV) parameter derived from laser speckle flowgraphy. Ten treatment-naïve nAMD patients underwent measurements of mean, maximum, minimum, and differential RFV within a retinal arteriolar segment and a choroidal vessel segment outside the neovascular area. Measurement of retinal RFV (rRFV), choroidal RFV (cRFV), and subfoveal choroidal thickness (SCT) was repeated 9 and 35 days after a single anti-VEGF injection. The treatment caused a statistically significant decrease in the mean rRFV, mean cRFV, and SCT during the follow-up (p < 0.05). At the intermediate visit, the mean cRFV and SCT were − 17.6% and − 6.4% compared to baseline, respectively. However, at the final measurement, the mean cRFV was not different from the baseline value, which indicated waning of the anti-VEGF effect. In conclusion, a single anti-VEGF injection in treatment-naïve nAMD resulted in a decrease in retinal arteriolar and choroidal perfusion, according to the RFV parameter, which is a promising tool to simultaneously assess retinal and choroidal perfusion changes in response to anti-VEGF therapy.
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15
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Sugisaki K, Inoue T, Yoshikawa K, Kanamori A, Yamazaki Y, Ishikawa S, Uchida K, Iwase A, Araie M. Factors Threatening Central Visual Function of Advanced Glaucoma Patients: A Prospective Longitudinal Observational Study. Ophthalmology 2021; 129:488-497. [PMID: 34890684 DOI: 10.1016/j.ophtha.2021.11.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 11/17/2021] [Accepted: 11/29/2021] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To identify risk factors for further deterioration of central visual function in advanced glaucoma eyes. DESIGN Prospective observational 5-year study. PARTICIPANTS Advanced glaucoma patients with well controlled intraocular pressure (IOP), the mean deviation (MD) of Humphrey Field Analyzer 24-2 program (HFA 24-2) ≤ -20 decibels and best-corrected visual acuity (BCVA) ≥ 20/40. METHODS The HFA10-2 test and BCVA examination were performed every 6 months and the HFA 24-2 test every 12 months for 5 years. The Cox proportional hazards model was used to identify risk factors for deterioration of HFA10-2 and 24-2 results and BCVA. MAIN OUTCOME MEASURES Deterioration of HFA 10-2 results was defined by the presence of the same ≥ 3 points with negative total deviation slope ≤ -1 decibel/year at P < 0.01 in ≥ 3 consecutive tests, that of HFA 24-2 results as an increase ≥ 2 in the Advanced Glaucoma Intervention Study (AGIS) score in ≥ 2 consecutive tests and that of BCVA as an increase of ≥ 0.2 in the log MAR in ≥ 2 consecutive tests. RESULTS A total of 175 advanced glaucoma eyes of 175 patients (mean age, 64.1 years; mean baseline IOP, 13.2 mmHg; mean logMAR, 0.02; Mean HFA 24-2 and 10-2 MD, -25.9 and -22.9 decibels, respectively) were included. The mean IOP during follow-up was 13.0 mmHg. The probabilities of deterioration in HFA 10-2 and 24-2 results and BCVA were 0.269 ± 0.043 (standard error), 0.173 ± 0.031 and 0.194 ± 0.033, respectively, at 5 years. Lower BCVA at baseline (P=0.012) was significantly associated with further deterioration of HFA 10-2 results. Better HFA24-2 MD (P<0.001) and use of systemic antihypertensive agents (P=0.009) were significantly associated with further deterioration of HFA 24-2 results, and a greater β-peripapillary atrophy area/disc area ratio (P<0.001), use of systemic antihypertensive agents (P=0.025) and lower BCVA (P=0.042) were significantly associated with further deterioration of BCVA, respectively. CONCLUSIONS In advanced glaucoma eyes with well controlled IOP, BCVA, β-peripapillary atrophy area/disc area ratio and use of systemic antihypertensive agents were significant prognostic factors for further deterioration of central visual function.
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Affiliation(s)
- Kenji Sugisaki
- Department of Ophthalmology, International University of Health and Welfare, Mita Hospital, Tokyo, Japan; Department of Ophthalmology, University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Toshihiro Inoue
- Department of Ophthalmology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | | | - Akiyasu Kanamori
- Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | - Shinichiro Ishikawa
- Department of Ophthalmology, Saga University Faculty of Medicine, Saga, Japan
| | | | | | - Makoto Araie
- Department of Ophthalmology, University of Tokyo Graduate School of Medicine, Tokyo, Japan; Sekikawa Hospital, Tokyo, Japan
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16
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Li Y, Li S, Wang Y, Zhou J, Yang J, Ma J. Effects of isometric resistance exercise of the lower limbs on intraocular pressure and ocular perfusion pressure among healthy adults: A meta-analysis. J Fr Ophtalmol 2021; 44:1596-1604. [PMID: 34454773 DOI: 10.1016/j.jfo.2021.05.005] [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: 03/26/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND The main risks for glaucoma are increased intraocular pressure (IOP) and decreased ocular perfusion pressure (OPP). This review aims to examine the potential impact of lower limb isometric resistance exercise on intraocular pressure and ocular perfusion pressure. METHOD A meta-analysis was conducted to determine the potential impact of isometric exercise on IOP and OPP. The literature on the relationship between isometric resistance exercise and IOP was systematically searched according to the "Cochrane Handbook" in the databases of Pubmed, Web of Science, EBSCO, and Scopus through December 31, 2020. The search terms used were "exercise," "train," "isometric," "intraocular pressure," and "ocular perfusion pressure," and the mean differences of the data were analyzed using the Stata 16.0 software, with a 95% confidence interval. RESULTS A total of 13 studies, which included 268 adult participants consisting of 162 men and 106 women, were selected. All the exercise programs that were included were isometric resistance exercises of the lower limbs with intervention times of 1min, 2min, or 6min. The increase in IOP after intervention was as follows: I2=87.1%, P=0.001 using random-effects model combined statistics, SMD=1.03 (0.48, 1.59), and the increase in OPP was as follows: I2=94.5%, P=0.001 using random-effects model combined statistics, SMD=2.94 (1.65, 4.22), with both results showing high heterogeneity. CONCLUSION As isometric exercise may cause an increase in IOP and OPP, therefore, people with glaucoma and related high risk should perform isometric exercise with caution.
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Affiliation(s)
- Y Li
- Zhengzhou Shengda University, Zhengzhou, China
| | - S Li
- Universiti Sains Malaysia, Kelantan, Malaysia
| | - Y Wang
- Inner Mongolia University, Inner Mongolia, China
| | - J Zhou
- Universiti Sains Malaysia, Kelantan, Malaysia
| | - J Yang
- Tangshan Hongci Hospital, Tangshan, China
| | - J Ma
- Hebei University of Architecture, Zhangjiakou, China.
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17
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Iwase C, Iwase T, Tomita R, Akahori T, Yamamoto K, Ra E, Terasaki H. Changes in pulse waveforms in response to intraocular pressure elevation determined by laser speckle flowgraphy in healthy subjects. BMC Ophthalmol 2021; 21:303. [PMID: 34416871 PMCID: PMC8379756 DOI: 10.1186/s12886-021-02070-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 08/14/2021] [Indexed: 11/27/2022] Open
Abstract
Background The influences of intraocular pressure (IOP) elevations on the pulse waveform in the optic nerve head (ONH) were evaluated using laser speckle flowgraphy (LSFG) in normal subjects. Methods This prospective cross-sectional study was conducted at the Nagoya University Hospital. An ophthalmodynamometer was pressed on the sclera to increase the IOP by 20 mmHg or 30 mmHg for 1 min (experiment 1, 16 subjects) and by 30 mmHg for 10 min (experiment 2, 10 subjects). The mean blur rate (MBR) and the eight pulse waveform parameters determined using LSFG were measured before, immediately after and during an IOP elevation, and after the IOP returned to the baseline pressure. Results A significant elevation in the IOP and a significant reduction in the ocular perfusion pressure (OPP) were found after applying the ophthalmodynamometer (both, P < 0.001). The blowout score (BOS) reduced significantly (P < 0.001), and the flow acceleration index (FAI; P < 0.01) and resistivity index (RI; P < 0.001) increased significantly immediately after increasing the IOP by 20 or 30 mmHg (experiment 1). The BOS reduced significantly (P < 0.001), and the FAI (P < 0.01) and RI (P < 0.001) increased significantly after the IOP elevation by 30 mmHg in both experiment 2 and 1. However, the BOS and RI recovered significantly at time 10 compared to that in time 0 (immediately after IOP elevation) during the 10-min IOP elevation (P < 0.001 and P = 0.008, respectively). Conclusions In conclusion, the BOS, FAI, and RI of the pulse waveforms changed significantly with an acute elevation in the IOP. The change should be related to the larger difference between the maximum and minimum MBRs during the IOP elevation.
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Affiliation(s)
- Chie Iwase
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan. .,Department of Ophthalmology, Akita University Graduate School of Medicine, 1-1-1 Hondou, Akita-city, Akita, 010-8543, Japan.
| | - Takeshi Iwase
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Department of Ophthalmology, Akita University Graduate School of Medicine, 1-1-1 Hondou, Akita-city, Akita, 010-8543, Japan
| | - Ryo Tomita
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomohiko Akahori
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kentaro Yamamoto
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Eimei Ra
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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18
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Tamplin MR, Broadhurst KA, Vitale AH, Hashimoto R, Kardon RH, Grumbach IM. Longitudinal Testing of Retinal Blood Flow in a Mouse Model of Hypertension by Laser Speckle Flowgraphy. Transl Vis Sci Technol 2021; 10:16. [PMID: 34003901 PMCID: PMC7884297 DOI: 10.1167/tvst.10.2.16] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose The purpose of this study was to investigate the applicability of laser speckle flowgraphy (LSFG) for a longitudinal study of blood flow parameters in mice before, during, and after continuous infusion of angiotensin-II. Methods Normotensive C57BL/6J mice were imaged by LSFG at one (n = 22) or three sessions (n = 10). Two additional cohorts were imaged by LSFG before, during, and after continuous infusion of angiotensin-II by minipump for 2 or 4 weeks (n = 6 and 8, respectively). Retinal blood flow, vascular resistance, and total area of retinal vascular flow, a surrogate of vascular remodeling and vasoconstriction, were determined at each time point. Results During infusion of angiotensin-II for 2 weeks, decreased retinal blood flow and area of vascular flow, as well as increased vascular resistance, were observed. These changes were reversed 1 week after the end of angiotensin-II infusion. In mice infused with angiotensin-II for 4 weeks, decreased retinal blood flow and increased vascular resistance persisted at 6 weeks postinfusion, despite a decrease in blood pressure. Conclusions Arterial hypertension, induced by continuous angiotensin-II infusion, results in reduced retinal blood flow, increased vascular resistance, and decrease in area of intravascular blood flow within retinal arterioles and venules. Sustained vasoconstriction 6 weeks after the end of a 4-week period of angiotensin-II infusion may indicate vascular remodeling after a period of chronic hypertension. Translational Relevance Retinal LSFG is useful for serial investigation of blood flow in mouse models and provides a novel approach for translational studies on the microvascular effects of hypertension in vivo.
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Affiliation(s)
- Michelle R Tamplin
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Kimberly A Broadhurst
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Anthony H Vitale
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Ryuya Hashimoto
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Randy H Kardon
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Iowa City Veterans Affairs Healthcare System, Iowa City, IA, USA
| | - Isabella M Grumbach
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.,Iowa City Veterans Affairs Healthcare System, Iowa City, IA, USA
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19
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Calzetti G, Mora P, Romani A, Ottonelli G, Pareti A, Gandolfi S, Schmetterer L, Carta A. Optic nerve head and peripapillary perfusion as assessed with laser speckle flowgraphy in non-arteritic anterior ischaemic optic neuropathy. Acta Ophthalmol 2021; 99:e445-e446. [PMID: 32701205 DOI: 10.1111/aos.14555] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/27/2020] [Accepted: 06/21/2020] [Indexed: 11/27/2022]
Affiliation(s)
| | - Paolo Mora
- Ophthalmology Unit University Hospital of Parma Parma Italy
| | | | | | | | | | - Leopold Schmetterer
- Singapore Eye Research Institute Singapore Singapore
- Nanyang Technological University Singapore Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program Duke‐NUS Medical School Singapore Singapore
- Department of Clinical Pharmacology Medical University of Vienna Vienna Austria
- Center for Medical Physics and Biomedical Engineering Medical University of Vienna Vienna Austria
| | - Arturo Carta
- Ophthalmology Unit University Hospital of Parma Parma Italy
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20
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Li H, Sun J, Wang H, Wang Y, Wang Z, Li J. Evaluation of hemodynamic changes in nonarteritic anterior ischemic optic neuropathy using multimodality imaging. Quant Imaging Med Surg 2021; 11:1932-1945. [PMID: 33936976 DOI: 10.21037/qims-20-699] [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: 11/06/2022]
Abstract
Background Nonarteritic anterior ischemic optic neuropathy (NAION) patients experience hypo-perfusion in the short posterior ciliary arteries (SPCAs), however, the cause of hypo-perfusion is unclear. Real-time dynamic hemodynamic observations may provide clues into specific NAION pathogenic mechanisms. We aim to analyze hemodynamic changes occurring in NAION using multimodality imaging. Our specific focus is identifying pathogenic mechanisms underlying SPCA insufficiency in NAION. Methods Three-dimensional arterial spin labeling (3D ASL) magnetic resonance imaging (MRI) and three-dimensional time-of-flight (3D-TOF) magnetic resonance angiography (MRA) were performed on 25 NAION patients (50 eyes) and 22 (44 eyes) normal cases were recruited. The diameter of the initial part of the ophthalmic artery and internal carotid artery siphon were measured using MRA. Blood vessel identification and blood flow (BF) were detected using 3D ASL MRI. We measured BF values of the optic nerve head (ONH) region of the retina/choroid complex, optic nerve (ON), temporal lobe, and occipital lobe. Results We studied 32 NAION affected eyes, 18 NAION uninvolved eyes, and 44 normal eyes. Diameter of the initial part of ophthalmic artery in the NAION affected eyes was significantly larger than the uninvolved eyes (P=0.026). Diameter of the NAION eyes was 1.33±0.19 mm [mean ± standard deviation (SD)], uninvolved eyes were 1.15±0.21 mm. At a photolabeling delay times (PLD) of 1,500 and 2,500 ms, BF of the ONH and ON in NAION affected eyes was significantly less than uninvolved and normal eyes (pONH <0.001 both at 1,500 and 2,500 ms, pON <0.001 and pON =0.001 at 1,500 and 2,500 ms, respectively). ONH of uninvolved eyes was also significantly less than normal eyes. Additionally, BF of the ONH region correlated with temporal lobe BF, with an R2=0.3231 and 0.2397 at 1,500 and 2,500 ms, respectively. BF of the ONH region also correlated with occipital lobe BF, with an R2=0.2534 and 0.4397 at 1,500 and 2,500 ms, respectively. ON and temporal lobe BF also correlated, with an R2=0.226 and 0.1504 at 1,500 and 2,500 ms, respectively. Conclusions Abnormal hemodynamics of small cerebral vessels existed prior to the onset of NAION. A candidate mechanism underlying NAION appears to be transient insufficiency of blood supply and decompensation of ocular vascular regulation.
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Affiliation(s)
- Hongyang Li
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Jiao Sun
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Huihui Wang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yanling Wang
- Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhenchang Wang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Jing Li
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
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21
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Zhang J, Strand K, Totillo M, Chen Q, Signorile JF, Jiang H, Wang J. Improvement of retinal tissue perfusion after circuit resistance training in healthy older adults. Exp Gerontol 2021; 146:111210. [PMID: 33385483 DOI: 10.1016/j.exger.2020.111210] [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: 10/20/2020] [Revised: 11/15/2020] [Accepted: 12/10/2020] [Indexed: 02/03/2023]
Abstract
PURPOSE To determine the retinal tissue perfusion (RTP) and its relation to cognitive function in healthy older people after an 8-week high-speed circuit resistance training program (HSCT). METHODS Eleven subjects in the HSCT group and seven age-matched non-training controls (CON) were recruited. The HSCT group trained 3 times per week for 8 weeks, while CON performed no formal training. One eye of each subject in both groups was imaged at baseline and at an 8-week follow-up, using a Retinal Function Imager to measure retinal blood flow (RBF). Retinal tissue perfusion (RTP) was calculated as RBF divided by the corresponding tissue volume. Cognitive function was assessed during both visits using the NIH Toolbox Fluid Cognition Battery. RESULTS RTP was 2.99 ± 0.91 nl·s-1·mm-3 (mean ± SD) at baseline and significantly increased to 3.77 ± 0.86 nl·s-1·mm-3 after training (P < 0.001) in the HSCT group, reflecting an increase of 26%. In the HSCT group, the Pattern Comparison Processing Speed Test (PAT) and Fluid Cognition Composite Score (FCS) were significantly increased after HSCT (P = 0.01). Furthermore, the changes in Flanker Inhibitory Control and Attention Test (FLNK) were positively correlated to increases in RTP (r = 0.80, P = 0.003). CONCLUSIONS This is the first prospective study to demonstrate that the increased RTP after HSCT was related to improved cognition in cognitively-normal elders, indicating RTP could be an imaging marker for monitoring cognitive changes due to physical activity in the elderly.
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Affiliation(s)
- Juan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Keri Strand
- Department of Kinesiology and Sports Sciences, University of Miami, FL, USA
| | - Matthew Totillo
- Department of Kinesiology and Sports Sciences, University of Miami, FL, USA
| | - Qi Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Joseph F Signorile
- Department of Kinesiology and Sports Sciences, University of Miami, FL, USA
| | - Hong Jiang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jianhua Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA.
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22
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Pappelis K, Choritz L, Jansonius NM. Microcirculatory model predicts blood flow and autoregulation range in the human retina: in vivo investigation with laser speckle flowgraphy. Am J Physiol Heart Circ Physiol 2020; 319:H1253-H1273. [PMID: 32986964 DOI: 10.1152/ajpheart.00404.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In this study, we mathematically predict retinal vascular resistance (RVR) and retinal blood flow (RBF), we test predictions using laser speckle flowgraphy (LSFG), we estimate the range of vascular autoregulation, and we examine the relationship of RBF with the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC). Fundus, optical coherence tomography (OCT), and OCT-angiography images, systolic/diastolic blood pressure (SBP/DBP), and intraocular pressure (IOP) measurements were obtained from 36 human subjects. We modeled two circulation markers (RVR and RBF) and estimated individualized lower/higher autoregulation limits (LARL/HARL), using retinal vessel calibers, fractal dimension, perfusion pressure, and population-based hematocrit values. Quantitative LSFG waveforms were extracted from vessels of the same eyes, before and during IOP elevation. LSFG metrics explained most variance in RVR (R2 = 0.77/P = 6.9·10-9) and RBF (R2 = 0.65/P = 1.0·10-6), suggesting that the markers strongly reflect blood flow physiology. Higher RBF was associated with thicker RNFL (P = 4.0·10-4) and GCC (P = 0.003), thus also verifying agreement with structural measurements. LARL was at SBP/DBP of 105/65 mmHg for the average subject without arterial hypertension and at 115/75 mmHg for the average hypertensive subject. Moreover, during IOP elevation, changes in RBF were more pronounced than changes in RVR. These observations physiologically imply that healthy subjects are already close to LARL, thus prone to hypoperfusion. In conclusion, we modeled two clinical markers and described a novel method to predict individualized autoregulation limits. These findings could improve understanding of retinal perfusion and pave the way for personalized intervention decisions, when treating patients with coexisting ophthalmic and cardiovascular pathologies.NEW & NOTEWORTHY We describe and test a new approach to quantify retinal blood flow, based on standard clinical examinations and imaging techniques, linked together with a physiological model. We use these findings to generate individualized estimates of the autoregulation range. We provide evidence that healthy subjects are closer to the lower autoregulation limit than thought before. This suggests that some retinas are less prepared to withstand hypoperfusion, even after small intraocular pressure rises or blood pressure drops.
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Affiliation(s)
- Konstantinos Pappelis
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Research School of Behavioural and Cognitive Neurosciences, Graduate School of Medical Sciences, University of Groningen, Groningen, The Netherlands
| | - Lars Choritz
- University Eye Clinic, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Nomdo M Jansonius
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Research School of Behavioural and Cognitive Neurosciences, Graduate School of Medical Sciences, University of Groningen, Groningen, The Netherlands
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23
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Tomita R, Iwase T, Ueno Y, Goto K, Yamamoto K, Ra E, Terasaki H. Differences in Blood Flow Between Superior and Inferior Retinal Hemispheres. Invest Ophthalmol Vis Sci 2020; 61:27. [PMID: 32421146 PMCID: PMC7405729 DOI: 10.1167/iovs.61.5.27] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine whether the blood flow in the superior retina is significantly different from that in the inferior retina, and to determine whether the posture affects the blood flow in the superior and inferior retina. Methods The blood flow in the vessels around the optic nerve head was measured by laser speckle flowgraphy in the sitting position in 68 healthy subjects. The blood flow in the superior peripapillary retina was compared with that in the inferior peripapillary retina. The measurements of the blood flow were performed in the sitting position, and the effect of switching to a supine position was determined at 2, 4, 6, 8, 10, and 30 minutes after the switch. Results The total relative flow volume (RFV)-all, RFV-artery, and RFV-vein were significantly greater in the superior retina than in the inferior retina (all P < 0.001). The mean diameter-all and mean diameter-artery in the superior retina were significantly larger than that in the inferior retina (all P < 0.05). The mean blur rate (MBR)-all, MBR-artery, and MBR-vein in the superior retina were also greater than that in the inferior retina (P < 0.001, P < 0.01, and P < 0.001, respectively). Although the ocular perfusion pressure was significantly changed with the postural alteration, the total RFV-all remained greater in the superior retina than in the inferior retina after the postural change. Conclusions Clinicians need to be aware of the differences in the blood flow between the superior and inferior retinal peripapillary area when considering the mechanisms of retinochoroidal diseases.
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24
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Hommer N, Kallab M, Szegedi S, Puchner S, Stjepanek K, Bauer M, Werkmeister RM, Schmetterer L, Abensperg‐Traun M, Garhöfer G, Schmidl D. The Effect of Orally Administered Dronabinol on Optic Nerve Head Blood Flow in Healthy Subjects-A Randomized Clinical Trial. Clin Pharmacol Ther 2020; 108:155-161. [PMID: 31977076 PMCID: PMC7325313 DOI: 10.1002/cpt.1797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/04/2020] [Indexed: 02/04/2023]
Abstract
It has been hypothesized that besides its intraocular pressure (IOP) lowering potential, tetrahydrocannabinol (THC) may also improve ocular hemodynamics. The aim of the present study was to investigate whether single oral administration of dronabinol, a synthetic THC, alters optic nerve head blood flow (ONHBF) and its regulation in healthy subjects. The study was carried out in a randomized, placebo-controlled, double-masked, two-way crossover design in 24 healthy subjects. For each study participant, 2 study days were scheduled, on which they either received capsules containing 5 mg dronabinol or placebo. ONHBF was measured with laser Doppler flowmetry at rest and while the study participants performed isometric exercise for 6 minutes to increase mean arterial blood pressure (MAP). This was repeated 1 hour after drug intake. Ocular perfusion pressure (OPP) was calculated as 2/3MAP-IOP. Dronabinol was well tolerated and no cannabinoid-related psychoactive effects were reported. Neither administration of dronabinol nor placebo had an effect on IOP, MAP, or OPP. In contrast, dronabinol significantly increased ONHBF at rest by 9.5 ± 8.1%, whereas placebo did not show a change in ONHBF (0.3 ± 7.4% vs. baseline, P < 0.001 between study days). Dronabinol did not alter the autoregulatory response of ONHBF to isometric exercise. In conclusion, the present data indicate that low-dose dronabinol increases ONHBF in healthy subjects without affecting IOP, OPP, or inducing psychoactive side effects. In addition, dronabinol does not alter the autoregulatory response of ONHBF to an experimental increase in OPP. Further studies are needed to investigate whether this effect can also be observed in patients with glaucoma.
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Affiliation(s)
- Nikolaus Hommer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Martin Kallab
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Stephan Szegedi
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Stefan Puchner
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Kristina Stjepanek
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Martin Bauer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - René M. Werkmeister
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Leopold Schmetterer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Singapore Eye Research InstituteSingaporeSingapore
- Lee Kong Chian School of MedicineNanyang Technological UniversitySingaporeSingapore
- Ophthalmology and Visual Sciences Academic Clinical ProgramDuke‐NUS Medical SchoolSingaporeSingapore
- SERI‐NTU Advanced Ocular Engineering (STANCE)SingaporeSingapore
- Institute of OphthalmologyBaselSwitzerland
| | | | - Gerhard Garhöfer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Doreen Schmidl
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
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25
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Calzetti G, Mora P, Favilla S, Ottonelli G, Devincenzi G, Carta A, Tedesco S, Mursch-Edlmayr A, Garhöfer G, Gandolfi S, Schmetterer L. Assessment of Choroidal Neovascularization Perfusion: A Pilot Study With Laser Speckle Flowgraphy. Transl Vis Sci Technol 2020; 9:9. [PMID: 32821481 PMCID: PMC7401962 DOI: 10.1167/tvst.9.5.9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/03/2020] [Indexed: 12/01/2022] Open
Abstract
Purpose The purpose of this study was to quantify perfusion in the area of choroidal neovascularization (CNV) using laser speckle flowgraphy (LSFG) before and after intravitreal anti-vascular endothelial growth factor (VEGF) injection. Methods Retrospective case series. Fifteen eyes of 15 patients with treatment-naïve CNV due to age-related macular degeneration (AMD) and with available LSFG images were included. The main outcome was the mean blur rate (MBR) quantified as a measure of perfusion within the CNV area observed on indocyanine green angiography. Twelve patients had available longitudinal data until one month after the injection, used to evaluate changes in perfusion, central macular thickness (CMT), visual acuity, and ocular perfusion pressure. Reproducibility of LSFG measurements was investigated at each time point from two images taken within five minutes. Results Intraclass correlation coefficients for LSFG measurements were higher than 0.8 indicating excellent reproducibility. There was a significant decrease in perfusion after one week (-26.4 ± 14.4%; P = 0.027), whereas, after one month, perfusion was no longer significantly different from baseline (P = 0.121). CMT showed a progressive decrease over the follow-up period. Changes in perfusion were strongly correlated with changes in CMT after one week, but not thereafter. Conclusions This pilot study suggests a method to select a region in the CNV area to quantify perfusion using LSFG. MBR could represent a parameter possibly related to regrowth of the CNV after anti-VEGF treatment. Large-scale studies are needed to assess the usefulness of LSFG in defining re-treatment criteria for neovascular AMD. Translational Relevance LSFG technology to quantify perfusion could provide useful biomarkers for therapeutic management of CNV.
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Affiliation(s)
| | - Paolo Mora
- Ophthalmology Unit, University Hospital of Parma, Parma, Italy
| | | | | | | | - Arturo Carta
- Ophthalmology Unit, University Hospital of Parma, Parma, Italy
| | | | - Anna Mursch-Edlmayr
- Department of Ophthalmology, Kepler University Clinic, Johannes Kepler University, Linz, Austria
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Singapore Eye Research Institute, Singapore.,Nanyang Technological University, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Institute of Ophthalmology, Basel, Switzerland
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26
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Popa-Cherecheanu A, Schmidl D, Werkmeister RM, Chua J, Garhöfer G, Schmetterer L. Regulation of Choroidal Blood Flow During Isometric Exercise at Different Levels of Intraocular Pressure. Invest Ophthalmol Vis Sci 2019; 60:176-182. [PMID: 30640970 DOI: 10.1167/iovs.18-24992] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose There is evidence that choroidal blood flow (ChBF) is regulated in a complex way during changes in ocular perfusion pressure (OPP). We hypothesized that ChBF regulates better in response to changes in mean arterial pressure (MAP) than in intraocular pressure (IOP). Methods Eighteen volunteers (mean age, 26 years) were recruited for a randomized, three-way crossover design. MAP was varied via isometric exercise. IOP was either kept normal or elevated by 10 or 20 mm Hg by using a suction cup. Subfoveal ChBF was measured continuously for 8 minutes with laser Doppler flowmetry and OPP was calculated as 2/3*MAP-IOP. For data analysis, values from all subjects were pooled according to either IOP or MAP values, and correlation analyses were done. Results When data were grouped according to IOP, no correlation was observed between ChBF and MAP, but ChBF was lower the higher the IOP (P < 0.001). When data were grouped according to MAP, a significant correlation was found between ChBF and IOP (P < 0.001). When data were pooled according to IOP, the correlation between ChBF and OPP was weaker (P < 0.05). The OPP at which ChBF significantly increased from baseline was 61.3% ± 4.9% without suction cup, 65.2% ± 3.5% when IOP was increased by 10 mm Hg, and slightly lower when IOP was increased by 20 mm Hg (56.3% ± 4.8%, P = 0.07), but this effect did not reach the level of significance. Conclusions The present study provides further evidence that the regulation of ChBF during changes in OPP is controlled by complex mechanisms in humans and has less capacity to adapt to IOP elevation than to MAP increase.
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Affiliation(s)
- Alina Popa-Cherecheanu
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Ophthalmology, Emergency University Hospital, Bucharest, Romania
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
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27
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Kiyota N, Shiga Y, Ichinohasama K, Yasuda M, Aizawa N, Omodaka K, Honda N, Kunikata H, Nakazawa T. The Impact of Intraocular Pressure Elevation on Optic Nerve Head and Choroidal Blood Flow. Invest Ophthalmol Vis Sci 2019; 59:3488-3496. [PMID: 30025080 DOI: 10.1167/iovs.18-23872] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To use laser speckle flowgraphy (LSFG) to assess blood flow (BF) in the optic nerve head (ONH) tissue and choroid during elevated intraocular pressure (IOP). Methods This prospective study included 20 eyes of 20 healthy volunteers. The testing protocol had a baseline phase, two elevated IOP phases (+10 and +20 mm Hg), and a recovery phase. IOP was elevated by pushing against the eyelid with a novel tubular device attached to the LSFG apparatus. Measurement parameters in each phase included: LSFG-derived mean blur rate (MBR) and flow acceleration index (FAI); systemic parameters, and IOP. The % change against baseline was calculated for each phase. The protocol was repeated five times to calculate the coefficient of variation (CV) for % change MBR and to determine the effect of mydriasis on % change MBR. We compared % change MBR and FAI and evaluated the relationship between % change ocular perfusion pressure (OPP) and MBR in the choroid and ONH tissue. Results The % change MBR was highly reproducible (CV: 6.1-8.7%) and not affected by mydriasis (P = 0.57-0.96). The % change MBR and FAI were higher in the ONH tissue than choroid during IOP elevation (P = 0.04). The % change OPP and MBR showed positive linear correlations and two-segmental linear correlations in the choroid and ONH tissue, respectively (P < 0.01). Conclusion Hemodynamics during IOP elevation differ in the choroid and ONH tissue. LSFG enables highly reproducible assessment of the dynamic autoregulation of ocular BF in the ONH tissue.
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Affiliation(s)
- Naoki Kiyota
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Yukihiro Shiga
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Kohei Ichinohasama
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Masayuki Yasuda
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Naoko Aizawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Kazuko Omodaka
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Naoto Honda
- Development Sec. 9, Medical Development Department, Eye Care Division, NIDEK Co., Ltd, Aichi, Japan
| | - Hiroshi Kunikata
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Development Sec. 9, Medical Development Department, Eye Care Division, NIDEK Co., Ltd, Aichi, Japan.,Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan
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28
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Bata AM, Fondi K, Witkowska KJ, Werkmeister RM, Hommer A, Vass C, Resch H, Schmidl D, Popa‐Cherecheanu A, Chua J, Garhöfer G, Schmetterer L. Optic nerve head blood flow regulation during changes in arterial blood pressure in patients with primary open-angle glaucoma. Acta Ophthalmol 2019; 97:e36-e41. [PMID: 30218499 PMCID: PMC6492118 DOI: 10.1111/aos.13850] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 05/20/2018] [Indexed: 01/07/2023]
Abstract
PURPOSE Abnormal autoregulation of optic nerve head blood flow (ONHBF) has been postulated to play an important role in primary open-angle glaucoma (POAG). We used laser Doppler flowmetry (LDF) to estimate quantitatively the ONHBF and compared ONHBF autoregulation between glaucoma patients and healthy controls during isometric exercise. METHODS Forty patients with POAG and 40 healthy age- and sex-matched subjects underwent three periods of isometric exercise, each consisting of 2 min of handgripping. Optic nerve head blood flow (ONHBF) was measured continuously using LDF. Systemic blood pressure, intraocular pressure and ocular perfusion pressure were assessed in all participants. RESULTS Isometric exercise was associated with an increase in ocular perfusion pressure during all handgripping periods in both groups (p < 0.001). However, there was no change in ONHBF in either group. Three of the glaucoma patients and two of the healthy subjects showed a consistent 10% decrease in blood flow during isometric exercise, in spite of an increase in their blood pressure. This difference between groups was not significant (p = 0.61). Four other glaucoma subjects showed a consistent increase in blood flow of more than 10% during isometric exercise, whereas this was not seen in healthy subjects (p = 0.035). CONCLUSION This study suggests that abnormal ONHBF autoregulation is more often seen in patients with POAG than healthy control subjects. The relationship to the glaucoma disease process is currently unknown and requires further investigation.
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Affiliation(s)
- Ahmed M. Bata
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Klemens Fondi
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | | | - René M. Werkmeister
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Anton Hommer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria,Department of OphthalmologySanatorium HeraViennaAustria
| | - Clemens Vass
- Department of OphthalmologyMedical University of ViennaViennaAustria
| | - Hemma Resch
- Department of OphthalmologyMedical University of ViennaViennaAustria
| | - Doreen Schmidl
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria,Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Alina Popa‐Cherecheanu
- Department of OphthalmologyEmergency University HospitalBucharestRomania,Carol Davila University of Medicine and PharmacyBucharestRomania
| | | | - Gerhard Garhöfer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria
| | - Leopold Schmetterer
- Department of Clinical PharmacologyMedical University of ViennaViennaAustria,Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria,Singapore Eye Research InstituteSingaporeSingapore,Lee Kong School of MedicineNanyang Technological UniversitySingaporeSingapore,Ophthalmology and Visual Sciences Academic Clinical ProgramDuke‐NUS Medical SchoolSingaporeSingapore
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29
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Wada Y, Higashide T, Nagata A, Sugiyama K. Effects of ripasudil, a rho kinase inhibitor, on blood flow in the optic nerve head of normal rats. Graefes Arch Clin Exp Ophthalmol 2019; 257:303-311. [PMID: 30474717 DOI: 10.1007/s00417-018-4191-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 10/21/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To evaluate the effect of topically administrated ripasudil, a rho kinase inhibitor, on blood flow in the optic nerve head (ONH) of normal rats. METHODS Ripasudil (0.4%) or placebo was administered in the right eye of normal Brown Norway rats in a double-blind manner. Laser speckle flowgraphy was measured in the ONH of the right eye 20 or 40 min after a single instillation and before and after 7 or 14 days of twice daily instillation. Mean blur rate was evaluated in the total area (MA), the vessel region (MV), and the tissue region (MT). Intraocular pressure (IOP), blood pressure, ocular perfusion pressure (OPP), and heart rate were also recorded at each time point. RESULTS After a single instillation, MV was significantly larger at 40 min than 20 min in the ripasudil group (P = 0.044) and was significantly lower in the placebo group (P = 0.023). MA and MV 40 min after instillation were significantly larger in the ripasudil group than in the placebo group (P = 0.022 and P = 0.006, respectively). After continuous instillation, MA and MV in the ripasudil group significantly increased from baseline after 7 and 14 days of treatment (both P < 0.05) and MA, MV, and MT were significantly higher than in the placebo group (MA: 7 and 14 days, P < 0.01; MV: 7 days, P = 0.003, and 14 days, P = 0.012; MT: 7 days, P = 0.046). There were no significant changes in IOP, blood pressure, or OPP after single or continuous instillation. CONCLUSIONS Topical instillation of ripasudil increased blood flow around the ONH in the eyes of normal rats.
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Affiliation(s)
- Yasushi Wada
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa, 920-8641, Japan
- Ophthalmology, National Hospital Organization Kanazawa Medical Center, Kanazawa, Japan
| | - Tomomi Higashide
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
| | - Atsushi Nagata
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa, 920-8641, Japan
- Ophthalmology, National Hospital Organization Kanazawa Medical Center, Kanazawa, Japan
| | - Kazuhisa Sugiyama
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa, 920-8641, Japan
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Postnov DD, Erdener SE, Kilic K, Boas DA. Cardiac pulsatility mapping and vessel type identification using laser speckle contrast imaging. BIOMEDICAL OPTICS EXPRESS 2018; 9:6388-6397. [PMID: 31065436 PMCID: PMC6491022 DOI: 10.1364/boe.9.006388] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/07/2018] [Indexed: 05/02/2023]
Abstract
Systemic flow variations caused by the cardiac cycle can play a role or be an important marker in both normal and pathological conditions. The shape, magnitude and propagation speed of the flow pulse reflect mechanical properties of the vasculature and are known to vary significantly with vascular diseases. Most conventional techniques are not capable of imaging cardiac activity in the microcirculation due to spatial and/or temporal resolution limitations and instead make inferences about propagation speed by making measurements at two points along an artery. Here, we apply laser speckle contrast imaging to images with high spatial resolution in the high frequency harmonics of cardiac activity in the cerebral cortex of a mouse. We reveal vessel dependent variation in the cardiac pulse activity and use this information to automatically identify arteries and veins.
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Affiliation(s)
- Dmitry D. Postnov
- Department of Biomedical Engineering, Boston University, 24 Cummington Mall, Boston, MA 02215,
USA
- Department of Biomedical Sciences, Copenhagen University, Blegdamsvej 3, 2200 Copenhagen N,
Denmark
| | - Sefik Evren Erdener
- Department of Biomedical Engineering, Boston University, 24 Cummington Mall, Boston, MA 02215,
USA
| | - Kivilcim Kilic
- Department of Biomedical Engineering, Boston University, 24 Cummington Mall, Boston, MA 02215,
USA
| | - David A. Boas
- Department of Biomedical Engineering, Boston University, 24 Cummington Mall, Boston, MA 02215,
USA
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Evaluation of flicker induced hyperemia in the retina and optic nerve head measured by Laser Speckle Flowgraphy. PLoS One 2018; 13:e0207525. [PMID: 30485331 PMCID: PMC6261588 DOI: 10.1371/journal.pone.0207525] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 11/01/2018] [Indexed: 11/19/2022] Open
Abstract
Purpose The coupling between neural activity and blood flow is a physiological key principle of ocular blood flow regulation. The current study was performed to investigate whether Laser speckle flowgraphy (LSFG), a commercially available technique for measuring blood flow, is capable to assess flicker-induced haemodynamic changes in the retinal and optic nerve head (ONH) circulation. Methods Twenty healthy subjects were included in this cross sectional study. A commercial LSFG instrument was used to measure blood flow at the ONH as well as in retinal vessels before and during stimulation with flickering light. Mean blur rate (MBR), a measure of relative blood flow velocity, was obtained for the ONH and relative flow volume (RFV) a measure of relative blood flow of the respective retinal vessels. Results Stimulation with flicker light increased ONH MBR by +17.5%±6.6% (p<0.01). In retinal arteries, flicker stimulation led an increase of +23.8±10.0% (p<0.05) in total RFV. For retinal veins, an increase of +23.1%±11.0 (p<0.05) in total RFV was observed during stimulation. A higher response was observed in nasal RFV compared to temporal RFV in retinal arteries (nasal: +28.9%±20.0%; temporal: +20.4%±17.6%, p<0.05) and veins (nasal: +28.3%±19.6%; temporal +17.8%±18.9%, p<0.05). Conclusion As shown previously with other techniques, flicker stimulation leads to an increase in retinal and optic nerve head blood flow. Our results indicate that LSFG is an appropriate method for the quantification of retinal and ONH blood flow during visual stimulation and may be used as a non-invasive, easy to use tool to assess neuro-vascular coupling in humans.
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Anele UA, Ratz PH, Colhoun AF, Roberts S, Musselman R, Vince RA, Speich JE, Klausner AP. Potential vascular mechanisms in an ex vivo functional pig bladder model. Neurourol Urodyn 2018; 37:2425-2433. [PMID: 29777585 DOI: 10.1002/nau.23710] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/13/2018] [Indexed: 12/29/2022]
Abstract
AIMS Chronic ischemia is a recognized factor in the pathophysiology of underactive bladder (UAB). Although relative ischemia (ie, low blood flow) is known to occur during filling, little is known regarding the pathophysiology that leads to UAB. Therefore, we developed an ex vivo functional porcine model to investigate the role of transient ischemia and whether autoregulation, a mechanism that maintains tissue oxygenation in certain vital organs, also exists in the bladder. METHODS Using bladders from slaughtered pigs, we prepared an isolated perfused model where we studied the effects of bladder perfusion flow rate on perfusion pressure and tissue oxygenation during the filling phase. Bladders were perfused at an initial flow rate of 20 mL/min and then clamped in a sequentially decreasing stepwise manner down to no flow and back to the initial flow rate. RESULTS We found a linear relationship between flow rate and perfusion pressure until the flow rate decreased below 5 mL/min at which point the vascular resistance decreased; however, tissue pO2 remained stable after an initial decline. CONCLUSIONS These findings suggest that there may be an intrinsic autoregulatory mechanism in the bladder that allows it to undergo cyclic episodes of relative ischemia during its normal function. Factors that overcome this mechanism such as complete or chronic ischemia may be critical in the progression to detrusor underactivity and thereby highlight the importance of intervention during the early phases of this disease process.
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Affiliation(s)
- Uzoma A Anele
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Paul H Ratz
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Andrew F Colhoun
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Sydney Roberts
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia
| | - Ryan Musselman
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia
| | - Randy A Vince
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - John E Speich
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia
| | - Adam P Klausner
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, Virginia
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Laser speckle flowgraphy derived characteristics of optic nerve head perfusion in normal tension glaucoma and healthy individuals: a Pilot study. Sci Rep 2018; 8:5343. [PMID: 29593269 PMCID: PMC5871884 DOI: 10.1038/s41598-018-23149-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/27/2018] [Indexed: 11/08/2022] Open
Abstract
The purpose of this prospective, case control study was to investigate the differences in optic nerve head blood flow measured with Laser Speckle Flowgraphy (LSFG) between Caucasian patients with normal tension glaucoma and healthy subjects. It included 20 eyes from 20 Caucasian patients with diagnosis of normal tension glaucoma and 20 eyes from age- and sex-matched healthy individuals. In the glaucoma group the antiglaucomatous therapy was paused 3 weeks prior to the investigations. Measurement of optic nerve head blood flow was performed with LSFG. The mean blur rate was obtained for different vascular compartments of the optic nerve head. Parameters for the characterization of pulse-waveform of the mean blur rate were calculated. It was shown that the mean blur rate was significantly lower in the glaucoma group compared to the control group (P < 0.001). The significant differences in the pulse-waveform parameters blow out time (P = 0.028) and flow acceleration time index (P < 0.001) indicate a flatter curve in NTG patients. In conclusion, LSFG can detect differences in optic nerve head blood flow between eyes with normal tension glaucoma and healthy eyes.
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Calzetti G, Fondi K, Bata AM, Luft N, Wozniak PA, Witkowska KJ, Bolz M, Popa-Cherecheanu A, Werkmeister RM, Schmidl D, Garhöfer G, Schmetterer L. Assessment of choroidal blood flow using laser speckle flowgraphy. Br J Ophthalmol 2018; 102:1679-1683. [PMID: 29472236 PMCID: PMC6287569 DOI: 10.1136/bjophthalmol-2017-311750] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 01/15/2018] [Accepted: 02/03/2018] [Indexed: 11/26/2022]
Abstract
Background/aims There is considerable interest in novel techniques to quantify choroidal blood flow (CBF) in humans. In the present study, we investigated a novel technique to measure CBF based on laser speckle flowgraphy (LSFG) in healthy subjects. Methods This study included 31 eyes of 31 healthy, non-smoking subjects aged between 19 and 74 years. A commercial LSFG instrument was used to measure choroidal vessel diameter (CVD) and relative flow volume (RFV) in choroidal vessels that were identified on fundus photos, an approach that was used previously only for retinal vessels. The reproducibility and the effect of isometric exercise on these parameters were investigated. The latter was compared with measurement of subfoveal CBF using laser Doppler flowmetry (LDF). Results Intraclass correlation coefficients for CVD and RFV were higher than 0.8 indicating excellent reproducibility. During isometric exercise, we observed an increase in ocular perfusion pressure of approximately 60% (P<0.001). The increase in RFV and CBF was lower, but also highly significant versus baseline (at minute 6 of isometric exercise: RFV 10.5%±4.2%, CBF 8.3%±3.6%; P<0.001 each) indicating choroidal autoregulation. Conclusion LSFG may be a novel approach to study blood flow in choroidal vessels. Data are reproducible and show good agreement with LDF data. Trial registration number NCT02102880, Results.
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Affiliation(s)
- Giacomo Calzetti
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Department of Ophthalmology, University of Parma, Parma, Italy
| | - Klemens Fondi
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Ahmed M Bata
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Nikolaus Luft
- Department of Ophthalmology, Kepler University Hospital, Linz, Austria.,Center for Refractive Therapy, University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Piotr A Wozniak
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | | | - Matthias Bolz
- Department of Ophthalmology, Kepler University Hospital, Linz, Austria
| | - Alina Popa-Cherecheanu
- Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Ophthalmology, Emergency University Hospital, Bucharest, Romania
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Singapore Eye Research Institute, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
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Comparison of Optic Nerve Head Blood Flow Autoregulation among Quadrants Induced by Decreased Ocular Perfusion Pressure during Vitrectomy. BIOMED RESEARCH INTERNATIONAL 2018; 2017:6041590. [PMID: 29362713 PMCID: PMC5738581 DOI: 10.1155/2017/6041590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/20/2017] [Indexed: 11/18/2022]
Abstract
Purpose The present study aimed to examine changes in optic nerve head (ONH) blood flow autoregulation in 4 quadrants (superior, nasal, inferior, and temporal) with decreased ocular perfusion pressure (OPP) during vitrectomy in order to determine whether there is a significant difference of autoregulatory capacity in response to OPP decrease at each ONH quadrant. Methods This study included 24 eyes with an epiretinal membrane or macular hole that underwent vitrectomy at Toho University Sakura Medical Center. Following vitrectomy, the tissue mean blur rate (MBR), which reflects ONH blood flow, was measured. Mean tissue MBRs in the four quadrants were generated automatically in the software analysis report. Measurements were conducted before and 5 and 10 min after intraocular pressure (IOP) elevation of approximately 15 mmHg in the subjects without systemic disorders. Results The baseline tissue MBR of the temporal quadrant was significantly lower than that of the other 3 quadrants (all P < 0.05). However, the time courses of tissue MBR in response to OPP decrease were not significantly different among the four quadrants during vitrectomy (P = 0.23). Conclusions There is no significant difference in the autoregulatory capacity of the four ONH quadrants in patients without systemic disorders during vitrectomy.
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