scholarly journals Effect of Changing Heart Rate on the Ocular Pulse and Dynamic Biomechanical Behavior of the Optic Nerve Head

2019 ◽  
Author(s):  
Yuejiao Jin ◽  
Xiaofei Wang ◽  
Sylvi Febriana Rachmawati Irnadiastputri ◽  
Rosmin Elsa Mohan ◽  
Tin Aung ◽  
...  
Keyword(s):  
Heart Rate ◽  
Optic Nerve ◽  
Optic Nerve Head ◽  
Solid Phase ◽  
Loss Modulus ◽  
Academic Research ◽  
Fluid Phase ◽  
Biomechanical Behavior ◽  
Pulse Volume ◽  
Ocular Pulse

ABSTRACTPurposeTo study the effect of changing heart rate on the ocular pulse and the dynamic biomechanical behaviour of the optic nerve head (ONH) using a comprehensive mathematical model.MethodsIn a finite element model of a healthy eye, a biphasic choroid consisted of a solid phase with connective tissues and a fluid phase with blood, and the lamina cribrosa (LC) was viscoelastic as characterized by a stress-relaxation test. We applied arterial pressures at 18 ocular entry sites (posterior ciliary arteries) and venous pressures at four exit sites (vortex veins). In the model, the heart rate was varied from 60 bpm to 120 bpm (increment: 20 bpm). We assessed the ocular pulse amplitude (OPA), pulse volume, ONH deformations and the dynamic modulus of the LC at different heart rates.ResultsWith an increasing heart rate, the OPA decreased by 0.04 mmHg for every 10 bpm increase in heart rate. The ocular pulse volume decreased linearly by 0.13 µL for every 10 bpm increase in heart rate. The storage modulus and the loss modulus of the LC increased by 0.014 MPa and 0.04 MPa, respectively, for every 10 bpm increase in heart rate.conclusionsIn our model, the OPA, pulse volume, and ONH deformations decreased with an increasing heart rate, while the LC became stiffer. The effects of blood pressure / heart rate changes on ONH stiffening may be of interest for glaucoma pathology.SupportSingapore Ministry of Education, Academic Research Fund, Tier 2 (R-397-000-280-112).Commercial relationshipNone

scholarly journals Effect of Changing Heart Rate on the Ocular Pulse and Dynamic Biomechanical Behavior of the Optic Nerve Head

2020 ◽  
Vol 61 (4) ◽  
pp. 27
Author(s):  
Yuejiao Jin ◽  
Xiaofei Wang ◽  
Sylvi Febriana Rachmawati Irnadiastputri ◽  
Rosmin Elsa Mohan ◽  
Tin Aung ◽  
...  
Keyword(s):  
Heart Rate ◽  
Optic Nerve ◽  
Optic Nerve Head ◽  
Biomechanical Behavior ◽  
Ocular Pulse

scholarly journals Three-Dimensional Inflation Response of Porcine Optic Nerve Head Using High-Frequency Ultrasound Elastography

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Yanhui Ma ◽  
Elias Pavlatos ◽  
Keyton Clayson ◽  
Sunny Kwok ◽  
Xueliang Pan ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
High Frequency ◽  
Three Dimensional ◽  
3D Ultrasound ◽  
Least Square ◽  
Ultrasound Elastography ◽  
High Frequency Ultrasound ◽  
Biomechanical Behavior ◽  
Frequency Ultrasound

Abstract Characterization of the biomechanical behavior of the optic nerve head (ONH) in response to intraocular pressure (IOP) elevation is important for understanding glaucoma susceptibility. In this study, we aimed to develop and validate a three-dimensional (3D) ultrasound elastographic technique to obtain mapping and visualization of the 3D distributive displacements and strains of the ONH and surrounding peripapillary tissue (PPT) during whole globe inflation from 15 to 30 mmHg. 3D scans of the posterior eye around the ONH were acquired through full tissue thickness with a high-frequency ultrasound system (50 MHz). A 3D cross-correlation-based speckle-tracking algorithm was used to compute tissue displacements at ∼30,000 kernels distributed within the region of interest (ROI), and the components of the strain tensors were calculated at each kernel by using least square estimation of the displacement gradients. The accuracy of displacement calculation was evaluated using simulated rigid-body translation on ultrasound radiofrequency (RF) data obtained from a porcine posterior eye. The accuracy of strain calculation was evaluated using finite element (FE) models. Three porcine eyes were tested showing that ONH deformation was heterogeneous with localized high strains. Substantial radial (i.e., through-thickness) compression was observed in the anterior ONH and out-of-plane (i.e., perpendicular to the surface of the shell) shear was shown to concentrate in the vicinity of ONH/PPT border. These preliminary results demonstrated the feasibility of this technique to achieve comprehensive 3D evaluation of the mechanical responses of the posterior eye, which may provide mechanistic insights into the regional susceptibility in glaucoma.

scholarly journals The influences of gender and aging on optic nerve head microcirculation in healthy adults

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tatsuhiko Kobayashi ◽  
Tomoaki Shiba ◽  
Ayako Kinoshita ◽  
Tadashi Matsumoto ◽  
Yuichi Hori
Keyword(s):  
Heart Rate ◽  
Optic Nerve ◽  
Optic Nerve Head ◽  
Laser Speckle ◽  
Laser Speckle Flowgraphy ◽  
Strongly Correlated ◽  
Average Maximum ◽  
Mean Blur Rate ◽  
And Gender ◽  
Rbc Count

Abstract Potential differences in the nature of the influences of aging and gender on the optic nerve head (ONH) microcirculation, using laser speckle flowgraphy (LSFG) were evaluated. We studied 908 healthy subjects (men = 701, age: 50.0 ± 9.1 yrs, women = 208, 49.8 ± 9.5 yrs, p = 0.76). The average, maximum (Max), and minimum (Min) mean blur rate (MBR) in a heartbeat were evaluated. The parameters were analyzed separately for the tissue, vessels, and throughout the ONH (All). We investigated which MBR sections are correlated with gender and age by univariate and multivariate regression analyses. The Max MBR-All (r = −0.31) was most strongly correlated with gender (men = 1, women = 0). The Min MBR-All (r = −0.24) was most strongly correlated with age, followed by Min MBR-All (r = −0.20). The factors contributing independently to the Max MBR-All were gender (β = −0.15), pulse pressure, spherical refraction, ocular perfusion pressure, and red blood cell (RBC) count. The factors contributing independently to the Min MBR-Vessel were gender (β = −0.09), age (β = −0.25), body mass index, heart rate, and spherical refraction. The factors contributing independently to the Min-MBR-All were age (β = −0.22), heart rate, and RBC count. Our results revealed that gender differences influence the Max MBR, and aging influences the Min MBR. These correlations were stronger than that of average MBR.

scholarly journals Modeling the Origin of the Ocular Pulse and Its Impact on the Optic Nerve Head

2018 ◽  
Vol 59 (10) ◽  
pp. 3997 ◽  
Author(s):  
Yuejiao Jin ◽  
Xiaofei Wang ◽  
Liang Zhang ◽  
Jost B. Jonas ◽  
Tin Aung ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Ocular Pulse

A preliminary systematic review and meta-analysis on the effects of heart rate variability biofeedback on heart rate variability and respiration of athletes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jeffrey Cayaban Pagaduan ◽  
Yung-Sheng Chen ◽  
James William Fell ◽  
Sam Shi Xuan Wu
Keyword(s):  
Systematic Review ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Web Of Science ◽  
Meta Analysis ◽  
Academic Research ◽  
Experimental Studies ◽  
Quantitative Review ◽  
Heart Rate Variability Biofeedback ◽  
Randomized Control

Abstract To date, there is no quantitative review examining the influence of heart rate variability biofeedback (HRV BFB) on the athlete population. Such an undertaking may provide valuable information on the autonomic and respiration responses of athletes when performing HRV BFB. Thus, purpose of this preliminary systematic review and meta-analysis on the effects of HRV BFB on HRV and respiration of athletes. Searches of Springerlink, SportDiscus, Web of Science, PROQUEST Academic Research Library, Google Scholar, and ScienceDirect were conducted for studies that met the following criteria: (1) experimental studies involving athletes that underwent randomized control trial; (2) availability of HRV BFB as a treatment compared with a control (CON)/placebo (PLA); (3) any pre and post HRV variable and/or breathing frequency as dependent variable/s; and, (4) peer-reviewed articles written in English. Four out of 660 studies involving 115 athletes (25 females and 90 males) ages 16–30 years old were assessed in this review. Preliminary findings suggest the promising ability of HRV BFB to improve respiratory mechanics in athlete population. More work is needed to determine the autonomic modulatory effect of HRV BFB in athletes.

scholarly journals Choroidal microvasculature dropout is spatially associated with optic nerve head microvasculature loss in open-angle glaucoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min Kyung Song ◽  
Joong Won Shin ◽  
Jin Yeong Lee ◽  
Ji Wook Hong ◽  
Michael S. Kook
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Optical Coherence Tomography Angiography ◽  
Open Angle Glaucoma ◽  
Spatial Relationship ◽  
Vascular Supply ◽  
Open Angle ◽  
Regression Analyses ◽  
Angular Extent ◽  
Choroidal Vessels

AbstractThe presence of parapapillary choroidal microvasculature dropout (CMvD) may affect optic nerve head (ONH) perfusion in glaucoma patients, since parapapillary choroidal vessels provide vascular supply to the neighboring ONH. However, it remains to be determined whether the presence of parapapillary CMvD is associated with diminished perfusion in the nearby ONH. The present study investigated the spatial relationship between CMvD and ONH vessel density (ONH-VD) loss in open-angle glaucoma (OAG) eyes using optical coherence tomography angiography (OCT-A). This study included 48 OAG eyes with a single localized CMvD confined to the inferotemporal parapapillary sector and 48 OAG eyes without CMvD, matched for demographic and ocular characteristics. Global and regional ONH-VD values were compared between eyes with and without CMvD. The relationships between ONH-VD outcomes and clinical variables were assessed. ONH-VDs at the inferotemporal ONH sectors corresponding to the CMvD location were significantly lower in eyes with compared to those without CMvD. Multivariable linear regression analyses indicated that a lower inferotemporal ONH-VD was independently associated with CMvD presence and a greater CMvD angular extent (both P < 0.05). The localized presence of parapapillary CMvD in OAG eyes is significantly associated with ONH-VD loss in the neighboring ONH location, with a spatial correlation.

scholarly journals Coloboma of the Optic Nerve Head in Benbal Tiger Kittens (Panthera tigris tigris)

1985 ◽  
Vol 26 (1) ◽  
pp. 136-139
Author(s):  
H. H. Dietz ◽  
E. Eriksen ◽  
O. A. Jensen
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Panthera Tigris ◽  
Panthera Tigris Tigris
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