Diurnal variation of pulse waveform parameters determined by laser speckle flowgraphy on the optic nerve head in healthy subjects

Fukami, Marie; Iwase, Takeshi; Yamamoto, Kentaro; Ra, Eimei; Murotani, Kenta; Terasaki, Hiroko

doi:10.1097/md.0000000000008312

Cited by 9 publications

(4 citation statements)

References 36 publications

(42 reference statements)

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“…Using laser speckle flowgraphy, diurnal variations of optic nerve head and choroidal blood flow were reported with a trough at 9:00 h and a peak at 24:00 h and a trough at 15:00 h and a peak at 18:00 h, respectively 21 . The same group also reported diurnal variation in the waveform of the laser speckle flowgraphy waveforms 22 . By contrast, others have employed different techniques such as laser Doppler flowmetry, color Doppler imaging, laser interferometric measurement of fundus pulsation and did not observe diurnal variations of blood flow parameters 23 – 25 .…”

Section: Discussionmentioning

confidence: 89%

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Lin

Tan

et al. 2020

Sci Rep

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We evaluated the impact of diurnal variation on choroidal and retinal microvasculature and structural measurements using a swept-source optical coherence tomography angiography machine (SS-OCTA; PLEX Elite 9,000, Carl Zeiss Meditec, Inc., Dublin, USA). Fourteen participants who were without ocular diseases underwent SS-OCTA imaging using 3 × 3-mm 2 macular scan pattern on two separate days at five time points. Choriocapillaris flow voids were generated to determine its density (percentage), size (μm) and numbers. Perfusion densities of the large superficial vessels, as well as capillaries on superficial and deep vascular plexuses were generated from retinal angiograms. Subfoveal choroidal and retinal thicknesses were manually measured. Repeated-measures ANOVA was used to investigate the impact of diurnal variation on choroidal and retinal measurements. There was no observable diurnal pattern for any of the flow void features, in terms of the density, size and numbers. There was a significant diurnal pattern observed in the choroidal thickness, where it decreased progressively during the day (P < 0.005). As opposed to sub-foveal choroidal thickness, there does not appear to be significant diurnal variation in choriocapillaris flow voids in normal individuals. This suggests that alterations of choriocapillaris flow deficit seen in pathological eyes will not be confounded by the diurnal fluctuation.

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Section: Discussionmentioning

confidence: 89%

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Lin

Tan

et al. 2020

Sci Rep

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“…Our previous study showed that women had a lower BOS across the entire ONH than men 4 . A low BOS is associated with high resistivity 38 , and given that BOM is considered to be the inverse property of BOS 4 , a high BOM value corresponds to high resistivity. We showed a significant correlation between BOS and BOM, thus indicating that BOM represents the resistivity value in each region.…”

Section: Discussionmentioning

confidence: 99%

Novel superpixel method to visualize fundus blood flow resistivity in healthy adults

Okamoto

Takahashi

Kobayashi

et al. 2023

Sci Rep

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We aimed to perform superpixel segmentation of ocular blood flow maps obtained using laser speckle flowgraphy (LSFG) and investigate the effects of systemic parameters such as body weight, height, and sex on ocular blood flow resistivity. We studied 757 healthy participants (583 men, 174 women). We calculated the average beat strength over mean blur rate (BOM) as a LSFG resistivity index, as a function of age and sex using ordinary regions of interest (ROI) centered on the optic nerve head (ONH), the retinal vessels region and tissue around the ONH, and the choroid (CHD). We compared the ROI and superpixel-based methods, which are segmented based on image processing, for calculating the BOM. The sex differences in the BOM for the ONH, retinal-vessels region and tissue region of the ONH and CHD were significant for individuals aged ≤ 50 years (P < 0.01) but not those > 50 years old (P > 0.05). The average BOMs calculated using the ROI and superpixel methods were strongly correlated in the ONH (coefficient = 0.87, R2 = 0.8, P < 0.0001, n = 5465). In summary, a superpixel-segmented BOM map is suitable for two-dimensional visualization of ocular blood flow resistivity.

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“…First, we did not evaluate diurnal variations in ONH microcirculation. Because the ONH microcirculation measured by LSFG exhibited a significant diurnal fluctuation [32, 58], it may have influenced our results. However, the 1- and 3-month IOP, LSFG, BP, and HR measurements and the corresponding baseline measurements were performed at almost the same time.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the LSFG software provides numerous parameters characterizing the shape of the MBR waveform during one cardiac cycle (pulse waveform analyses) for assessment of the dynamics of ocular blood flow. The definitions and calculations of the pulse waveform parameters have been described in detail in previous studies [21, 22, 32, 33]. In the present study, five pulse waveform parameters were used for analysis (Figure 2): (1) Fluctuation is a parameter indicating the instability of the blood flow.…”

Section: Methodsmentioning

confidence: 99%

Pulse Waveform Analysis of the Ocular Blood Flow Using Laser Speckle Flowgraphy before and after Glaucoma Treatment

Masai

Ishida

Anraku

et al. 2019

Journal of Ophthalmology

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Although reduction in intraocular pressure (IOP) is the principle of glaucoma treatment, impaired ocular blood flow is believed to play a role in the progression of glaucoma. This study evaluated the effect of glaucoma treatment on pulse waveforms for optic nerve head (ONH) microcirculation in patients with glaucoma. Fifty-one subjects were included on the basis of the glaucoma treatment administered, which involved instillation of prostaglandin (PG) analogs (PG group; n = 28) or trabeculectomy (trabeculectomy group; n = 23). ONH blood flow, represented by the mean blur rate (MBRT) and pulse waveforms, was measured using laser speckle flowgraphy before and 1 and 3 months after treatment. Three months after treatment, IOP exhibited a significant decrease (p < 0.05). Although there was no significant change in MBRT after treatment, the acceleration time index (ATI) significantly decreased (p=0.034) in the PG group. In the trabeculectomy group, there was no significant change in the MBRT after treatment, while fluctuation (p=0.019) and blowout score (BOS) (p=0.036) exhibited significant decrease and increase, respectively. Multiple regression analysis showed that mean deviation was significantly associated with the rate of change in the BOS (p=0.013), age was a significant contributing factor for the rate of change in fluctuation in the trabeculectomy group, reflection was significantly associated with the ATI (p=0.037) in the in the PG group. Both glaucoma treatments can change the pulse waveforms, with MBRT remaining unchanged, and IOP reduction owing to the treatment may contribute to stable blood flow in the tissue area of the ONH. As impaired ocular blood flow plays a role in the progression of glaucomatous damage, it would be beneficial if glaucoma treatment could improve the stability of ONH microcirculation.

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Diurnal variation of pulse waveform parameters determined by laser speckle flowgraphy on the optic nerve head in healthy subjects

Cited by 9 publications

References 36 publications

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Novel superpixel method to visualize fundus blood flow resistivity in healthy adults

Pulse Waveform Analysis of the Ocular Blood Flow Using Laser Speckle Flowgraphy before and after Glaucoma Treatment

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