scholarly journals Hemodynamic Response of the Three Macular Capillary Plexuses in Dark Adaptation and Flicker Stimulation Using Optical Coherence Tomography Angiography

2019 ◽  
Vol 60 (2) ◽  
pp. 694 ◽  
Author(s):  
Peter L. Nesper ◽  
Hee Eun Lee ◽  
Alaa E. Fayed ◽  
Gregory W. Schwartz ◽  
Fei Yu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Dark Adaptation ◽  
Optical Coherence Tomography Angiography ◽  
Hemodynamic Response ◽  
Optical Coherence ◽  
Flicker Stimulation

scholarly journals Reversed Neurovascular Coupling on Optical Coherence Tomography Angiography Is the Earliest Detectable Abnormality before Clinical Diabetic Retinopathy

2020 ◽  
Vol 9 (11) ◽  
pp. 3523
Author(s):  
Yi Stephanie Zhang ◽  
Ilda Mucollari ◽  
Changyow C. Kwan ◽  
Gianna Dingillo ◽  
Jaspreet Amar ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Dark Adaptation ◽  
Optical Coherence Tomography Angiography ◽  
Neurovascular Coupling ◽  
Flow Index ◽  
Optical Coherence ◽  
Significant Difference ◽  
Capillary Plexus ◽  
Healthy Eyes

Diabetic retinopathy (DR) has traditionally been viewed as either a microvasculopathy or a neuropathy, though neurovascular coupling deficits have also been reported and could potentially be the earliest derangement in DR. To better understand neurovascular coupling in the diabetic retina, we investigated retinal hemodynamics by optical coherence tomography angiography (OCTA) in individuals with diabetes mellitus (DM) but without DR (DM no DR) and mild non-proliferative DR (mild NPDR) compared to healthy eyes. Using an experimental design to monitor the capillary responses during transition from dark adaptation to light, we examined 19 healthy, 14 DM no DR and 11 mild NPDR individuals. We found that the only structural vascular abnormality in the DM no DR group was increased superficial capillary plexus (SCP) vessel density (VD) compared to healthy eyes, while mild NPDR eyes showed significant vessel loss in the SCP at baseline. There was no significant difference in inner retinal thickness between the groups. During dark adaptation, the deep capillary plexus (DCP) VD was lower in mild NPDR individuals compared to the other two groups, which may leave the photoreceptors more susceptible to ischemia in the dark. When transitioning from dark to ambient light, both diabetic groups showed a qualitative reversal of VD trends in the SCP and middle capillary plexus (MCP), with significantly decreased SCP at 5 min and increased MCP VD at 50 s compared to healthy eyes, which may impede metabolic supply to the inner retina during light adaptation. Mild NPDR eyes also demonstrated DCP dilation at 50 s and 5 min and decreased adjusted flow index at 5 min in light. Our results show altered neurovascular responses in all three macular vascular plexuses in diabetic subjects in the absence of structural neuronal changes on high resolution imaging, suggesting that neurovascular uncoupling may be a key mechanism in the early pathogenesis of DR, well before the clinical appearance of vascular or neuronal loss.

Plexus-specific effect of flicker-light stimulation on the retinal microvasculature assessed with optical coherence tomography angiography

2021 ◽  
Vol 320 (1) ◽  
pp. H23-H28
Author(s):  
Martin Kallab ◽  
Nikolaus Hommer ◽  
Bingyao Tan ◽  
Martin Pfister ◽  
Andreas Schlatter ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Specific Effect ◽  
Optical Coherence ◽  
Specific Mechanism ◽  
Physiological Importance ◽  
Retinal Microvasculature ◽  
Capillary Plexus ◽  
Flicker Stimulation ◽  
Superficial Capillary Plexus

We present vessel density alterations in response to flicker stimulation using optical coherence tomography angiography and identified the superficial capillary plexus as the layer with the most pronounced effect. This points out the physiological importance of the microvasculature in mediating functional hyperemia and suggests a fine-tuned plexus-specific mechanism to meet cellular metabolic demands.

Optical coherence tomography angiography application to pigmented iris: Could a new index quantify blood flow?

2021 ◽  
pp. 112067212110334
Author(s):  
Stefano Lucentini ◽  
Kengo Ikesugi ◽  
Francesco Bonsignore ◽  
Cecilia Acuti Martellucci ◽  
Masahiko Sugimoto ◽  
...  
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Dark Adaptation ◽  
Pupil Size ◽  
Optical Coherence Tomography Angiography ◽  
Anterior Segment ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Quantify Blood Flow ◽  
Group D

Purpose: To assess the blood flow and vascular visibility of irises in relation to pigmentation and pupil size, using an anterior segment optical coherence tomography angiography (OCTA). Materials and methods: This is a cross-sectional study. OCTA images were acquired in the nasal and temporal quadrants from a cohort of 30 healthy subjects in photopic (miosis) and scotopic (mydriasis) conditions. Patients were divided according to iris color (less pigmented: group L vs more pigmented: group D). Vascular parameters (vessel density (VD), vessel length density (VLD), fractal dimension (FD)) were applied and compared among groups L and D, location and different pupil status. A novel vascular index called Luminance Index (LI) was developed and applied in order to quantify vascular flow and evaluate its variation in photopic and scotopic conditions. Multivariable analyses were performed to evaluate possible predictors of VD and LI. Results: No differences were found for all vascular measurements (VD, VDL, FD, LI) between nasal and temporal quadrants. All vascular measurements were higher in group L than in group D ( p < 0.05), except for LI and FD in photopic condition. In group L, all vascular parameters increased ( p < 0.001) after dark adaptation. In group D, only LI increased after dark adaptation ( p < 0.001). Pigmentation and iris thickness were significantly associated with VD in scotopic and photopic conditions, and with LI only in scotopic condition. Conclusions: Pigmentation still remains a major issue for vascular visibility. Quantitative and qualitative vascular changes follow pupil size variation. LI could be a new surrogate to quantify blood flow.

scholarly journals Optical coherence tomography angiography monitors human cutaneous wound healing over time

2018 ◽  
Vol 8 (2) ◽  
pp. 135-150 ◽  
Author(s):  
Anthony J. Deegan ◽  
Wendy Wang ◽  
Shaojie Men ◽  
Yuandong Li ◽  
Shaozhen Song ◽  
...  
Keyword(s):  
Wound Healing ◽  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Optical Coherence ◽  
Cutaneous Wound Healing ◽  
Cutaneous Wound ◽  
Over Time

scholarly journals Peripapillary and Macular Vessel Density in Dysthyroid Optic Neuropathy: An Optical Coherence Tomography Angiography Study

2019 ◽  
Vol 60 (6) ◽  
pp. 1863 ◽  
Author(s):  
Te Zhang ◽  
Wei Xiao ◽  
Huijing Ye ◽  
Rongxin Chen ◽  
Yuxiang Mao ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optic Neuropathy ◽  
Optical Coherence Tomography Angiography ◽  
Vessel Density ◽  
Optical Coherence ◽  
Dysthyroid Optic Neuropathy

scholarly journals Evaluating Retinal and Choroidal Perfusion Changes after Isometric and Dynamic Activity Using Optical Coherence Tomography Angiography

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 808
Author(s):  
Max Philipp Brinkmann ◽  
Nikolas Xavier Kibele ◽  
Michelle Prasuhn ◽  
Vinodh Kakkassery ◽  
Mario Damiano Toro ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Isometric Exercise ◽  
Dynamic Exercise ◽  
Exercise Heart Rate ◽  
Optical Coherence ◽  
Dynamic Activity ◽  
Capillary Plexus ◽  
Choroidal Perfusion

Optical coherence tomography angiography (OCTA) is a non-invasive tool for imaging and quantifying the retinal and choroidal perfusion state in vivo. This study aimed to evaluate the acute effects of isometric and dynamic exercise on retinal and choroidal sublayer perfusion using OCTA. A pilot study was conducted on young, healthy participants, each of whom performed a specific isometric exercise on the first day and a dynamic exercise the day after. At baseline and immediately after the exercise, heart rate (HR), mean arterial pressure (MAP), superficial capillary plexus perfusion (SCPP), deep capillary plexus perfusion (DCPP), choriocapillaris perfusion (CCP), Sattlers’s layer perfusion (SLP), and Haller’s layer perfusion (HLP) were recorded. A total of 34 eyes of 34 subjects with a mean age of 32.35 ± 7.87 years were included. HR as well as MAP increased significantly after both types of exercise. Both SCPP and DCPP did not show any significant alteration due to isometric or dynamic exercise. After performing dynamic exercise, CCP, SLP, as well as HLP significantly increased. Changes in MAP correlated significantly with changes in HLP after the dynamic activity. OCTA-based analysis in healthy adults following physical activity demonstrated a constant retinal perfusion, supporting the theory of autoregulatory mechanisms. Dynamic exercise, as opposed to isometric activity, significantly changed choroidal perfusion. OCTA imaging may represent a novel and sensitive tool to expand the diagnostic spectrum in the field of sports medicine.

Sign in / Sign up

Export Citation Format

Share Document