scholarly journals Longitudinal stability of retinal blood flow regulation in response to flicker stimulation and systemic hyperoxia in mice assessed with laser speckle flowgraphy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Junya Hanaguri ◽  
Harumasa Yokota ◽  
Masahisa Watanabe ◽  
Lih Kuo ◽  
Satoru Yamagami ◽  
...  
Keyword(s):  
Blood Flow ◽  
Vascular Function ◽  
Systemic Blood Pressure ◽  
Laser Speckle ◽  
Retinal Blood Flow ◽  
Laser Speckle Flowgraphy ◽  
Adult Mice ◽  
Ocular Perfusion ◽  
Vascular Area ◽  
Flicker Stimulation

AbstractThis study aimed to evaluate longitudinal changes in retinal blood flow in response to flicker stimulation and systemic hyperoxia in mice using a laser speckle flowgraphy (LSFG-Micro). The retinal blood flow in vascular area surrounding the optic nerve head was measured in 8-week-old male mice every 2 weeks until age 20-week. The coefficient of variation of retinal blood flow under resting condition was analyzed every 2 weeks to validate the consistency of the measurement. On day 1 of the experiment, retinal blood flow was assessed every 20 s for 6 min during and after 3 min flicker light (12 Hz) stimulation; on day 2, retinal blood flow was measured every minute for 20 min during and after 10 min systemic hyperoxia; and on day 3, electroretinography (ERG) was performed. Body weight, systemic blood pressure, and ocular perfusion pressure increased significantly with age, but the resting retinal blood flow and ERG parameters remained unchanged. Retinal blood flow significantly increased with flicker stimulation and decreased with systemic hyperoxia, independent of age. The LSFG-Micro provides consistent and reproducible retinal blood flow measurement in adult mice. Longitudinal assessments of retinal blood flow in response to flicker stimulation and systemic hyperoxia may be useful indexes for noninvasive monitoring of vascular function in retinas.

scholarly journals Microcirculatory model predicts blood flow and autoregulation range in the human retina: in vivo investigation with laser speckle flowgraphy

2020 ◽  
Vol 319 (6) ◽  
pp. H1253-H1273
Author(s):  
Konstantinos Pappelis ◽  
Lars Choritz ◽  
Nomdo M. Jansonius
Keyword(s):  
Blood Flow ◽  
Healthy Subjects ◽  
Imaging Techniques ◽  
Physiological Model ◽  
Laser Speckle ◽  
Retinal Blood Flow ◽  
Laser Speckle Flowgraphy ◽  
New Approach ◽  
Pressure Drops

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.

scholarly journals Differences of Retinal Blood Flow Between Arteries and Veins Determined by Laser Speckle Flowgraphy in Healthy Subjects

Medicine ◽  
2015 ◽  
Vol 94 (33) ◽  
pp. e1256 ◽  
Author(s):  
Takeshi Iwase ◽  
Eimei Ra ◽  
Kentaro Yamamoto ◽  
Hiroki Kaneko ◽  
Yasuki Ito ◽  
...  
Keyword(s):  
Blood Flow ◽  
Healthy Subjects ◽  
Laser Speckle ◽  
Retinal Blood Flow ◽  
Laser Speckle Flowgraphy ◽  
Arteries And Veins

Laser Speckle Flowgraphy for Retinal Blood Flow Analysis (I)

1989 ◽  
Vol 10 (3) ◽  
pp. 43-46
Author(s):  
Hitoshi Fujii ◽  
Makoto Araie ◽  
Shuichiro Eguchi ◽  
Takashi Yokokura
Keyword(s):  
Blood Flow ◽  
Flow Analysis ◽  
Laser Speckle ◽  
Retinal Blood Flow ◽  
Laser Speckle Flowgraphy ◽  
Blood Flow Analysis

scholarly journals Longitudinal Testing of Retinal Blood Flow in a Mouse Model of Hypertension by Laser Speckle Flowgraphy

2021 ◽  
Vol 10 (2) ◽  
pp. 16
Author(s):  
Michelle R. Tamplin ◽  
Kimberly A. Broadhurst ◽  
Anthony H. Vitale ◽  
Ryuya Hashimoto ◽  
Randy H. Kardon ◽  
...  
Keyword(s):  
Blood Flow ◽  
Mouse Model ◽  
Laser Speckle ◽  
Retinal Blood Flow ◽  
Laser Speckle Flowgraphy

scholarly journals Retinal blood flow dysregulation precedes neural retinal dysfunction in type 2 diabetic mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Junya Hanaguri ◽  
Harumasa Yokota ◽  
Masahisa Watanabe ◽  
Satoru Yamagami ◽  
Akifumi Kushiyama ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Blood Flow ◽  
Flow Regulation ◽  
Laser Speckle ◽  
Retinal Blood Flow ◽  
Implicit Time ◽  
Laser Speckle Flowgraphy ◽  
Neural Function ◽  
Glucose Levels

AbstractWe investigated and compared the susceptibility of retinal blood flow regulation and neural function in mice developing type 2 diabetes. The longitudinal changes in retinal neuronal function and blood flow responses to a 10-min systemic hyperoxia and a 3-min flicker stimulation were evaluated every 2 weeks in diabetic db/db mice and nondiabetic controls (db/m) from age 8 to 20 weeks. The retinal blood flow and neural activity were assessed using laser speckle flowgraphy and electroretinography (ERG), respectively. The db/db mice had significantly higher blood glucose levels and body weight. The resting retinal blood flow was steady and comparable between two groups throughout the study. Hyperoxia elicited a consistent decrease, and flicker light an increase, in retinal blood flow in db/m mice independent of age. However, these flow responses were significantly diminished in db/db mice at 8 weeks old and then the mice became unresponsive to stimulations at 12 weeks. Subsequently, the ERG implicit time for oscillatory potential was significantly increased at 14 weeks of age while the a-wave and b-wave amplitudes and implicit times remained unchanged. The deficiencies of flow regulation and neurovascular coupling in the retina appear to precede neural dysfunction in the mouse with type 2 diabetes.

scholarly journals Changes in Ocular Blood Flow after Ranibizumab Intravitreal Injection for Diabetic Macular Edema Measured Using Laser Speckle Flowgraphy

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Lisa Toto ◽  
Federica Evangelista ◽  
Pasquale Viggiano ◽  
Emanuele Erroi ◽  
Giada D’Onofrio ◽  
...  
Keyword(s):  
Blood Flow ◽  
Macular Edema ◽  
Diabetic Macular Edema ◽  
Ocular Blood Flow ◽  
Laser Speckle ◽  
Laser Speckle Flowgraphy ◽  
Prospective Clinical Study ◽  
Intravitreal Ranibizumab ◽  
Vascular Area ◽  
Retinal Artery

Purpose. To evaluate the effects of intravitreal ranibizumab (IVR) treatment on the blood flow of the optic nerve head (ONH) and of retinal vessels of the peripapillary region of eyes with diabetic macular edema (DME) assessed using laser speckle flowgraphy (LSFG). Methods. Forty eyes of 30 patients treated with IVR for DME were included in this prospective clinical study. Mean blur rate (MBR) and relative flow volume (RFV) of the ONH and of a superior retinal artery and an inferior retinal vein of the peripapillary region were measured using LSFG at baseline, 2 weeks (T1), and 1 month (T2) after IVR injection. In addition, best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were measured in all cases. Results. The BCVA improved and CRT decreased significantly during the follow-up period (p<0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p=0.046; MT, p=0.023; MV, p=0.025), with no significant change at T2 compared to T1. MBR of the retinal artery and vein changed significantly at 2 weeks after IVR and did not change significantly thereafter (p=0.004 and p=0.01, respectively). The median of RFV of the 2 vessels was 269.5 (221.6–285.5) and 306.8 (285.6–372.4) at baseline and 199.7 (152.4–204.7) and 259.1 (140.9–336.8) at 4 weeks, respectively (p=0.292 and p=0.002, respectively). Blowout time changed significantly in ONH from 47.6 (44.2–50.2) at baseline to 54.4 (46.8–65.3) at 1 month after IVR (p=0.001). Conclusion. IVR injection leads to a reduction of ocular blood flow both in the ONH and in the retinal peripapillary vessels associated with peripapillary vessel constriction. The reduction of CRT and related improvement of vision may be related to the changes in ocular blood flow.

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