Laser Speckle Flowgraphy Research Articles

Ocular circulation change in optic disc melanocytoma – a case report and a review of the literature

BackgroundOcular circulation in optic disc melanocytoma (ODM) has not yet been well evaluated. We quantitatively evaluated longitudinal changes in the morphology and circulation hemodynamics of the disc and macula using optical coherence tomography angiography (OCTA) and laser speckle flowgraphy (LSFG) in a patient with optic disc melanocytoma.Case presentationA 50-year-old woman was referred to our hospital due to a dark pigmented tumor over the superior optic disc area of the left eye noted on physical examination. At the first visit, the patient’s best-corrected visual acuity (BCVA) was 20/20 in both eyes, and the intraocular pressure (IOP) was 17 and 18 mmHg in the left and right eyes, respectively. Fluorescein angiography (FA) showed blockage of fluorescence in the topography of the lesion, and indocyanine green angiography (ICGA) showed hypofluorescence at all times. On LSFG, a low mean blur rate (MBR) was noted in the optic disc all area (MBRa) and tissue (MBRt) compared to the contralateral eye at the first visit and at the 3-month follow-up. A relatively low MBR was also detected in the macular area of the affected eye and the tumor itself. OCTA detected blood vessel networks in the deep retinal layer of the tumor. The visual field showed no specific defects. During follow-up, there was no tumor enlargement or vision decrease.ConclusionsWe found that a lower MBR of the disc and macula area was noted on LSFG in this patient with optic disc melanocytoma, and it was continually observed at the 3-month follow-up. Although blood vessel networks in the deep retinal layer of the tumor were detected by OCTA, vascular compromise in the surrounding disc area and macula was found. Therefore, these results further increase our knowledge about the role that circulation impairment plays in the pathogenesis of the disease while vision is unaffected.

Effects of Intravitreal Ranibizumab Injection to Treat Macular Edema due to Central Retinal Vein Occlusion on Choroidal Findings and Functional-Morphological Parameters

Introduction: Little research has examined the effects of anti-vascular endothelial growth factor therapy on subfoveal choroidal thickness (SCT), choroidal blood flow, aqueous flare, and humor levels of growth and inflammatory factors in patients with macular edema due to central retinal vein occlusion (CRVO). Methods: In 58 patients with macular edema due to CRVO treated by intravitreal ranibizumab injection (IRI), we retrospectively assessed best-corrected visual acuity (BCVA, assessed as the logarithm of the minimum angle of resolution [logMAR]), 8 aqueous factors (by suspension array), mean blur rate (MBR; estimated by laser speckle flowgraphy as a measure of choroidal blood flow), aqueous flare (with a laser flare meter), and SCT and central macular thickness (CMT; by optical coherence tomography). Results: After 4 weeks, IRI resulted in a significant improvement in BCVA and CMT and a significant reduction in SCT, choroidal MBR, and aqueous flare. SCT was significantly positively correlated with placental growth factor and significantly negatively correlated with platelet-derived growth factor-AA, and change in SCT was significantly negatively correlated with change in BCVA (logMAR). Aqueous flare was significantly negatively correlated with SCT. Conclusion: Growth and inflammatory factors may be associated with SCT, and changes in SCT may be associated with changes in BCVA after IRI to treat macular edema due to CRVO.

Effect of moderate-intensity treadmill exercise under different ambient temperatures on peripheral circulatory responses in young healthy adults

Exercise training has the potential for inducing enhancements in peripheral circulation, which can play important preventive and therapeutic roles in peripheral circulatory diseases. However, the relevant published studies show conflicting and inconclusive results. Furthermore, useful or optimum ambient temperature for this purpose has not yet been established. Therefore, we investigated the acute responses in peripheral circulation from exposure of healthy subjects to treadmill exercise under different ambient temperatures; A total of 12 young adult volunteers (males 6, females 6) randomly underwent three sessions of treadmill exercise for 30 min under three different ambient temperatures (10°C, 20°C, and 30°C), at a predetermined exercise intensity. Before and after the intervention, leg skin blood flow (SBF) was measured by laser Speckle flowgraphy and hand skin temperature (ST), by digital thermometry; After the cessation of treadmill exercise, compared to the corresponding baseline values, a significant increase in SBF was observed under all ambient temperature conditions (P<0.005). During intervention, ST showed a significant decrease at 10th min of intervention under all ambient temperatures (P<0.005) with a subsequent increasing trend in it. After intervention, a significant increase in ST was observed under 20°C condition only (P<0.05). Also, after intervention, the observed increase in systolic blood pressure was less significant under 20°C condition; Treadmill exercise appears to be a useful intervention modality in inducing improvements in peripheral circulation. However, exposure to treadmill exercise under or near 20°C ambient temperature might be recommended for the purpose.

Akimba Proliferative Diabetic Retinopathy Model: Understanding Molecular Mechanism and Drug Screening for the Progression of Diabetic Retinopathy.

As the prevalence of diabetes has reached epidemic proportions worldwide, diabetic retinopathy incidence is increasing rapidly. An advanced diabetic retinopathy (DR) stage can lead to a sight-threatening form. There is growing evidence showing diabetes causes a range of metabolic changes that subsequently lead to pathological modifications in the retina and retinal blood vessels. To understand the complex mechanism of the pathophysiology of DR, a precise model is not readily available. By crossbreeding the Akita and Kimba strains, a suitable proliferative DR model was acquired. This new Akimba strain manifests marked hyperglycemia and vascular changes, which resemble the early and advanced stage of DR.Here, we describe the breeding method, colony screening for experiments, and imaging techniques widely used to investigate the DR progression in this model. We elaborate step-by-step protocols to set up and perform fundus, fluorescein angiography, optical coherence tomography, and optical coherence tomography-angiogram to study retinal structural changes and vascular abnormalities. In addition, we show a method to label the leukocytes with fluorescence and laser speckle flowgraphy to examine the inflammation in the retina and retinal vessel blood flow speed, respectively. Lastly, we describe electroretinogram to evaluate the functional aspect of the DR transformations.

Retinal protection by fungal product theissenolactone B in a sodium iodate-induced AMD model through targeting retinal pigment epithelial matrix metalloproteinase-9 and microglia activity

Age-related macular degeneration (AMD) is the leading cause of low vision and blindness for which there is currently no cure. Increased matrix metalloproteinase-9 (MMP-9) was found in AMD and potently contributes to its pathogenesis. Resident microglia also promote the processes of chronic neuroinflammation, accelerating the progression of AMD. The present study investigates the effects and mechanisms of the natural compound theissenolactone B (LB53), isolated from Theissenia cinerea, on the effects of RPE dysregulation and microglia hyperactivation and its retinal protective ability in a sodium iodate (NaIO3)-induced retinal degeneration model of AMD. The fungal component LB53 significantly reduces MMP-9 gelatinolysis in TNF-α-stimulated human RPE cells (ARPE-19). Similarly, LB53 abolishes MMP-9 protein and mRNA expression in ARPE-19 cells. Moreover, LB53 efficiently suppresses nitric oxide (NO) production, iNOS expression, and intracellular ROS levels in LPS-stimulated TLR 4-activated microglial BV-2 cells. According to signaling studies, LB53 specifically targets canonical NF-κB signaling in both ARPE-19 and BV-2 microglia. In an RPE-BV-2 interaction assay, LB53 ameliorates LPS-activated BV-2 conditioned medium-induced MMP-9 activation and expression in the RPE. In NaIO3-induced AMD mouse model, LB53 restores photoreceptor and bipolar cell dysfunction as assessed by electroretinography (ERG). Additionally, LB53 prevents retinal thinning, primarily the photoreceptor, and reduces retinal blood flow from NaIO3 damage evaluated by optic coherence tomography (OCT) and laser speckle flowgraphy (LSFG), respectively. Our results demonstrate that LB53 exerts neuroprotection in a mouse model of AMD, which can be attributed to its anti-retinal inflammatory effects by impeding RPE-mediated MMP-9 activation and anti-microglia.

Ocular blood flow and myopia

AbstractPurpose: It has previously been found that imposing positive defocus changes axial length and choroidal thickness after only 30 minutes. In the present study, we investigated whether these changes may result from an altered choroidal blood flow.Methods: Eighteen young adult subjects watched a movie from a large screen (65 inch) in a dark room at 2 m distance. A fifteen‐minute wash‐out period was followed by 30 minutes of watching the movie with a monocular positive defocus (+2.5D). Changes in axial length and ocular blood flow were measured before and after the defocus, by using low‐coherent interferometer (LS 900, Haag‐Streit, Switzerland) and a laser speckle flowgraphy (LSFG) RetFlow unit (Nidek Co., LTD, Japan), respectively. Three regions were analysed: (1) the macular area, where choroidal blood flow can be measured, (2) the optic nerve head (ONH), and (3) retinal vessel segments.Results: Changes in choroidal blood flow were significantly and negatively correlated with changes in axial length that followed positive defocus in exposed eyes (R = −0.67, p < 0.01). The absolute values of changes in choroidal blood flow in the defocused eyes were significantly larger than in the fellow control eyes. ONH and retinal blood flow were not associated with the induced changes in axial length.Conclusions: Positive defocus selectively alters choroidal, but not retinal or ONH blood flow in young human subjects after short‐term visual exposure. The results suggest that blood flow modulation is involved in the mechanism of choroidal responses to optical defocus.

Retinal blood flow and oxygen saturation in patients previously infected with COVID‐19

AbstractPurpose: The SARS‐CoV‐2 pandemic has affected all countries in the world and is still ongoing. Although respiratory symptoms are the main manifestation of acute infection, there is also increasing evidence that neurological and vascular symptoms occur, and it is unknown whether residuals remain after patients have recovered. We therefore set out to investigate whether ocular vascular alterations remain after patients have recovered.Methods: Patients that had recovered from COVID‐19 infection within the last 6 months before inclusion and healthy age‐ and sex‐matched controls were recruited. Main inclusion criteria for patients were confirmed positive PCR test for SARS‐CoV‐2 in the medical history and positive testing for SARS‐CoV‐2 seroprevalence while controls had no history of COVID‐19 infection. Arteriovenous (AV) difference in oxygen saturation was calculated out of retinal arterial and venous oxygen saturation, which were measured with a commercially available Dynamic Vessel Analyser (DVA, Imedos, Germany). Retinal vessel diameters and arteriovenous ratio (AVR) were assessed using the same device. In addition, mean blur rate in the tissue area of the optic nerve head (MT) was quantified using laser speckle flowgraphy (LSFG, Nidek, Japan).Results: 29 patients that had recovered from moderate to severe COVID‐19 requiring hospitalization (mean age 35 ± 17 years) and 11 control subjects (mean age 36 ± 12 years) were included in the present study. No differences between groups regarding sex or concomitant diseases in the medical history were found. Body mass index (BMI) was significantly higher in patients that had recovered from COVID‐19 (27.5 ± 5.6 vs. 24.5 ± 2.8 m2/kg, p = 0.036). AVR as well as AV difference in oxygen saturation was significantly lower in patients compared to healthy controls (p = 0.021 for AVR and p = 0.023 for AV difference in oxygen saturation). MT in the optic nerve head also was significantly lower in patients (23.4 ± 10.1 a.u.) than in control subjects (47.3 ± 26.6 a.u., p < 0.001).Conclusions: The results of this study imply that retinal metabolism is still altered in patients after recovering from COVID‐19 infection. Longitudinal studies are required to investigate whether these changes in retinal vessels as well as optic nerve head blood flow are temporary or remain.

Choroidal hemodynamics in central serous chorioretinopathy after half-dose photodynamic therapy and the effects of smoking

This retrospective study aimed to evaluate choroidal hemodynamics after half-dose photodynamic therapy (PDT) for central serous chorioretinopathy (CSC) and the effects of smoking using laser speckle flowgraphy. This study included 29 eyes of 29 patients treated with half-dose PDT for CSC, who were followed-up for at least 6 months. The mean blur rate (MBR) in the PDT irradiation area (whole area), the pachyvessel (PV) area, non-PV (NPV) area, and filling delay (FD) area were assessed at baseline and 1, 3, and 6 months post-PDT, respectively. The MBR was also assessed by smoking status. The MBR significantly decreased from baseline in the whole, PV, NPV, and FD areas at all time points (P < 0.001). Of the 29 patients, 6 were never smokers, 13 were past smokers, and 10 were current smokers. At baseline, no significant difference was found in the MBR in the whole, PV, NPV, and FD areas among never, past, and current smokers. The MBR changes showed a significantly smaller decrease in current smokers than in never smokers in the whole (P = 0.021), PV (P = 0.009), and NPV (P = 0.034) areas, but not in the FD area (P = 0.172). Half-dose PDT for CSC reduced choroidal blood flow in the PDT-irradiated area, which was blunted by current smoking status.

Imposed positive defocus changes choroidal blood flow in young human subjects

PurposeIt has previously been found that imposing positive defocus changes axial length and choroidal thickness after only 30 min. In the present study, we investigated whether these changes may result from an altered choroidal blood flow.MethodsEighteen young adult subjects watched a movie from a large screen (65 in.) in a dark room at 2 m distance. A 15-min wash-out period was followed by 30 min of watching the movie with a monocular positive defocus (+ 2.5D). Changes in axial length and ocular blood flow were measured before and after the defocus, by using low-coherent interferometer (LS 900, Haag-Streit, Switzerland) and a laser speckle flowgraphy (LSFG) RetFlow unit (Nidek Co., LTD, Japan), respectively. Three regions were analyzed: (1) the macular area, where choroidal blood flow can be measured, (2) the optic nerve head (ONH), and (3) retinal vessel segments.ResultsChanges in choroidal blood flow were significantly and negatively correlated with changes in axial length that followed positive defocus in exposed eyes (R = − 0.67, p < 0.01). The absolute values of changes in choroidal blood flow in the defocused eyes were significantly larger than in the fellow control eyes (2.35 ± 2.16 AU vs. 1.37 ± 1.44 AU, respectively, p < 0.05). ONH and retinal blood flow were not associated with the induced changes in axial length.ConclusionsPositive defocus selectively alters choroidal, but not retinal or ONH blood flow in young human subjects after short-term visual exposure. The results suggest that blood flow modulation is involved in the mechanism of choroidal responses to optical defocus.

Acute Increase in Ocular Microcirculation Blood Flow Upon Cholesterol Removal. The Eyes Are the Window of the Heart

BackgroundLipoprotein 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. MethodsThis 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. ResultsAfter 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). ConclusionsA 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.

Close association between spreading depolarization and development of infarction under experimental ischemia in anesthetized male mice

Clinical and experimental evidence suggests that spreading depolarizations (SD) usually occur in patients with ischemic or hemorrhagic stroke when the gray matter of the brain is affected. In this study, we evaluated spatiotemporal changes of cerebral blood flow (CBF) during middle cerebral artery (MCA) occlusion and examined the relationship between SD occurrence and cerebral infarct development. In male isoflurane-anesthetized C57BL/6J mice, CBF changes over the ipsilateral parietal bone were recorded by laser speckle flowgraphy during and after transient (45 min, n = 22) or permanent occlusion (n = 22) of the distal MCA. Infarct volume was evaluated 24 hr after the operation. Upon MCA occlusion, CBF decreased by −55.6 ± 8.5 % in the lowest CBF and linearly recovered with increasing distance from the region. At 1–10 min after onset of occlusion, SD occurred and concentrically propagated from the core region, showing a decrease of CBF in the whole observed area along with a transient hyperemia and oligemia in the normal region. SD spontaneously re-occurred and propagated around the ischemic area in 37 % of mice, accompanied with a marked decrease of CBF in the core or a marked increase of CBF in the normal region. The CBF response to SDs gradually changed from the core to the normal area, depending upon the distance from the core region. Infarction was not observed in transiently (n = 2) or permanently (n = 4) occluded mice without SD. The infarct area tended to be larger with increasing number of SDs in transiently occluded mice. In conclusion, our findings suggest that the occurrence of SD during ischemia might elicit infarct formation and/or influence infarct development.

The relationship between choroidal blood flow and glaucoma progression in a Japanese study population.

To determine whether choroidal blood flow (BF) is related to visual field (VF) defect severity and progression in eyes with open-angle glaucoma (OAG). Retrospective and longitudinal. This study comprised 443 eyes of 285 OAG patients who underwent laser speckle flowgraphy (LSFG), optical coherence tomography, and visual-field (VF) testing at baseline. The patients were then observed for at least 2 years and at least 5 reliable VF tests were performed. In the LSFG images, we set regions of interest at the optic nerve head (ONH) and the parapapillary choroid to obtain ONH-tissue mean blur rate (MBR) and choroidal MBR, respectively. We used univariable and multivariable linear mixed-effects models to determine clinical factors associated with choroidal MBR at baseline. We also used a linear mixed-effects model to determine the contribution of ONH-tissue MBR and choroidal MBR to baseline mean deviation (MD) and to MD slope during follow-up, adjusting for potential confounding factors, including circumpapillary retinal nerve fiber layer thickness. Choroidal MBR was associated with age, MD slope, and ONH-tissue MBR (β = -0.181, P = 0.001; β = 0.134, P = 0.002; β = 0.096, P = 0.049, respectively). ONH-tissue MBR was associated with both MD and MD slope (β = 0.146, P = 0.004; β = 0.152, P = 0.009, respectively), whereas choroidal MBR was associated only with MD slope (β = 0.147, P = 0.005). LSFG-derived choroidal MBR might be a useful biomarker to predict VF defect progression in a Japanese population.

Acute uveitic phase of Vogt-Koyanagi-Harada disease: optic nerve head swelling, ocular blood flow and retinal oxygen metabolism.

To investigate the association of optic nerve head (ONH) swelling in the acute uveitic phase of Vogt-Koyanagi-Harada (VKH) disease with blood flow velocity in the choroid and ONH and oxygen saturation and diameter of retinal vessels. In this prospective study, 25 patients (50 eyes) were studied. Thirteen patients (26 eyes) had ONH swelling and 12 patients (24 eyes) had no ONH swelling. Laser speckle flowgraphy (LSFG) and retinal oximetry measurements were performed at presentation. In the ONH, mean blur rate (MBR)-vessel, representing blood flow velocity in retinal vessels, was significantly lower in the eyes affected by ONH swelling, while choroidal MBR was not significantly different. Eyes with ONH swelling had a significantly lower oxygen saturation in retinal venules, a significantly higher arteriovenous oxygen saturation difference and a significantly smaller calibre of retinal arterioles compared with eyes without ONH swelling. There were significant positive correlations between the MBR-vessel of the ONH and venular oxygen saturation and calibre of retinal arterioles. In addition, MBR-vessel of the ONH had a significant negative correlation with arteriovenous oxygen saturation difference. The occurrence of ONH swelling in the acute uveitic phase of VKH disease is associated with lower retinal blood flow velocity and smaller calibre of retinal arterioles as well as lower oxygen saturation in retinal venules and higher arteriovenous difference in oxygen saturation.

Reduced blood flow by laser speckle flowgraphy after 125I-plaque brachytherapy for uveal melanoma

BackgroundTo determine whether reductions in retinal and choroidal blood flow measured by laser speckle flowgraphy are detected after 125I-plaque brachytherapy for uveal melanoma.MethodsIn a cross-sectional study, retinal and choroidal blood flow were measured using laser speckle flowgraphy in 25 patients after treatment with 125I-plaque brachytherapy for uveal melanoma. Flow was analyzed in the peripapillary region by mean blur rate as well as in the entire image area with a novel superpixel-based method. Relationships between measures were determined by Spearman correlation.ResultsSignificant decreases in laser speckle blood flow were observed in both the retinal and choroidal vascular beds of irradiated, but not fellow, eyes. Overall, 24 of 25 patients had decreased blood flow compared to their fellow eye, including 5 of the 6 patients imaged within the first 6 months following brachytherapy. A significant negative correlation between blood flow and time from therapy was present.ConclusionsDecreases in retinal and choroidal blood flow by laser speckle flowgraphy were detected within the first 6 months following brachytherapy. Reduced retinal and choroidal blood flow may be an early indicator of microangiographic response to radiation therapy.

Changes in choroidal circulation hemodynamics during the menstrual cycle in young, healthy women.

PurposeThe current study aimed to investigate the time course of changes in choroidal circulation hemodynamics and their relationship to systemic circulation dynamics during the normal menstrual cycle in young, healthy women using laser speckle flowgraphy (LSFG).MethodsThis prospective study included 26 eyes from 13 young, healthy women (21.3 ± 4.0 years) with a normal menstrual cycle and 24 eyes from 12 young, healthy men (21.8 ± 4.4 years) as a control group. The macular mean blur rate (MBR), a quantitative index of relative blood flow velocity in the choroid, was measured using LSFG. MBR, intraocular pressure (IOP), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and ocular perfusion pressure (OPP) were evaluated in the late follicular phase and mid-luteal phase in women and at baseline and 10 days after baseline in men, respectively.ResultsIn the female group, IOP, SBP, DBP, MBP, and OPP values were significantly higher in the mid-luteal phase than those observed in the late follicular phase (P = 0.035, P < 0.001, P = 0.041, P = 0.001, P = 0.014, respectively). The average macular MBR values in the late follicular phase and mid-luteal phase were 12.7 ± 5.3 and 13.7 ± 6.6 (+7.7 ± 19.4%), representing a significant increase in the mid-luteal phase (P = 0.041). The rate of change in MBR exhibited a significant positive correlation with changes in DBP and MBP (R = 0.456, P = 0.019 and R = 0.474, P = 0.014). However, there were no significant changes in any of the factors in the male group during the study period.ConclusionsOur results suggest that in young, healthy women with a normal menstrual cycle, choroidal blood flow velocity decreases during the late follicular phase and increases during the mid-luteal phase, depending on systemic circulatory dynamics.

Correlation Between Laser Speckle Flowgraphy and OCT-Derived Retinal and Choroidal Metrics in Healthy Human Eye.

PurposeTo investigate the correlation between laser speckle flowgraphy (LSFG) signals and the quantitative metrics derived from optical coherence tomography (OCT) in normal eyes.MethodsLSFG, 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.ResultsTwelve 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.ConclusionsLSFG 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 RelevanceThis study illustrates the dominant source of the LSFG signals in the eye.

Waveform changes of laser speckle flowgraphy in the temporal optic nerve head and peripapillary atrophy after trabeculectomy in open-angle glaucoma

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.

26-LB: Risk Factors of Retinal Oxygen Metabolism and Hemodynamics for Retinopathy in Diabetes

Purpose: Alterations in retinal oxygen metabolism and hemodynamics are signs of impending diabetic retinopathy (DR) . The study aimed to investigate risk factors of the retinal oxygen metabolism and hemodynamics for non-proliferative DR (NPDR) . Method: The study included 166 eyes from 50 age-matched healthy subjects, 80 diabetic patients without DR (Non-DR) , and 36 NPDR. Each subjects underwent basic medical history and dilated fundal examinations including colour fundus photography, and custom-built multimodal ophthalmic device with function of retinal oximetry and laser speckle flowgraphy. Retinal metabolism was evaluated by retinal arteriolar (SO2a) , and venular (SO2v) oxygen saturation, while retinal hemodynamics was evaluated by related parameters such as diastolic duration, flow acceleration index (FAI) and resistance index (RI) . Continuous variables were analyzed by one-way analysis of variance, and categorical variables were analyzed by the chi-square test for three groups. The logistic regression model was used to obtain the risk factors of Non-DR developing into NPDR. Result: The SO2a and SO2v of NPDR and Non-DR were higher significantly than controls (p&amp;lt;0.05) . There were significant difference among three groups in hemodynamics parameters, including diastolic duration, FAI, blowout score, and RI. The greatest risk factors of Non-DR developing into NPDR descending order were higher RI (odds ratio (OR) =5.84, 95% confidence interval (CI) =1.32-25.78) , shorter diastolic duration (OR= 3.46, 95% CI=1.35-8.87) , higher glycosylated hemoglobin A1c (OR=1.82, 95% CI=1.15-2.88) , lower body mass index (OR=1.74, 95% CI=1.19-2.55) , longer duration of diabetic mellitus (OR=1.21, 95% CI=1.05-1.39) , smaller age (OR=1.17, 95% CI=1.04-1.32) , higher SO2v (OR=1.16, 95% CI=1.00-1.34) , higher systolic blood pressure (OR=1.05, 95% CI=1.00-1.10) . Conclusion: Both NPDR and Non-DR show abnormality in retinal oxygen metabolism and hemodynamics. Diastolic duration, RI, and SO2v are independent risk factors in NPDR. Disclosure Z. Jin: None. C. Zhou: None. Q. Ren: None. Z. Zhou: None. B. Zhang: None. F. Wang: None. J. Chen: None. D. Liao: None. Y. Lu: None. Y. Yang: None. J. Li: None. Funding Guangdong Basic and Applied Basic Research Foundation (2021A1515110747) .

Effects of aging and exercise habits on blood flow profile of the ocular circulation.

We examined the effects of aging and exercise habits on the ocular blood flow (OBF) and its profiles throughout the optic nerve head region and choroidal area. We hypothesized that exercise habits reduce the stiffness of vessels in the ocular circulation, which generally increases with aging. Participants in a medical checkup program (698 males and 192 females aged 28 to 80 years) were categorized into 2 groups (with and without exercise habits) based on participant self-reporting and the definition of the Ministry of Health, Labor and Welfare of Japan (MHLW). OBF in the right eye was measured and analyzed using laser speckle flowgraphy. The blowout time (BOT), which is the time during which the blood flow is higher than half of the mean of the minimum and maximum signals during one heartbeat, was calculated as an index of the blood flow profile. BOT has been used as an indicator of the flexibility of blood vessels. BOT significantly decreased with aging. Neither the self-reported nor MHLW-based exercise habits significantly affected the ocular circulation. These results indicate that the stiffness of the ocular vessels increases with aging, and this cannot be prevented by exercise habits.

Оценка возрастных изменений параметров глазного кровотока диска зрительного нерва методом лазерной спекл-флоуграфии

The most common eye diseases, including glaucoma and diabetic retinopathy, are associated with impaired perfusion of the eye. To date, LSFG is a reliable method for quantifying ocular circulation. Purpose. To assess the ocular blood flow age- related changes using Laser Speckle Flowgraphy (LSFG). Material and methods. This cross-sectional study included 90 eyes of 45 healthy, non-smoking volunteers, between 20 to 75 years old. LSFG instrument was applied to measure ocular blood flow at the optic nerve head. The mean blur rate (MBR), a measure of relative blood flow velocity, was obtained for different regions of the ONH. Three parameters of ocular perfusion derived from the pulse-waveform analysis of MBR for big vessels (MV) and microcirculatory bad (MT) including blowout time (BOT), blowout score (BOS) and resistivity index (RI) were also recorded. Results. Artifact-free LSFG images meeting the quality criteria for automated image analysis were obtained. Measurements of MBR showed excellent repeatability. MBR-related blood flow indices exhibited significant age dependence (p&lt;0.05). BOT, BOS and RI changes also analysed. Conclusion. LSFG represents a reliable method for the quantitative assessment of ocular blood flow. Our data affirms that the LSFG-parameters may be useful biomarkers of ocular perfusion for age-related and patologic changes. Key words: ocular perfusion, microcirculation, optic nerve disc, laser speckle flowgraphy, LSFG, glaucoma, diabetic retinopathy