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Development of laser speckle blood flowmeter for evaluating the physiological function of skin
摘要： Objective: We developed and demonstrated laser speckle ?owgraphy (LSFG) for two-dimensional (2D) skin blood ?ow (SBF) measurements to facilitate the noninvasive comparisons of SBF between individuals. Approach: By using morphing technology with a face mesh to compare SBF spatial distributions among individuals, we examined the practicability of SBF measurement with LSFG. Main results: (1) The uniformity of SBF measurement was demonstrated by examinations at different distances and angles for healthy subjects. (2) Mean blur rate (MBR)—a blood ?ow index of LSFG—exhibited signi?cant correlation with the thermal diffusion method (TDM)—an established blood ?ow measurement method—suggesting that MBR is an effective index of SBF. (3) Blowout time, the half-width duration/duration of one cardiac cycle, exhibited signi?cant negative correlation with age and positive correlation with stratum corneum hydration. Signi?cance: These results suggest that LSFG is useful for evaluating SBF-related skin properties, and it has signi?cant potential in medicine and cosmetology.
关键词： aging,stratum corneum hydration,skin blood ?ow,laser speckle ?owgraphy,morphing,strain-gauge plethysmography,thermal diffusion
更新于2025-09-23 15:19:57
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<p>Correlation between laser speckle flowgraphy and optical coherence tomography angiography measurements in normal and glaucomatous eyes</p>
摘要： Purpose: To investigate the relationship between laser speckle ?owgraphy (LSFG) and optical coherence tomography angiography (OCTA) measurements of the peripapillary retina and optic nerve head (ONH) in normal eyes and eyes with primary open-angle glaucoma (POAG). Patients and methods: One eye from each of 46 normal subjects and mild and moderate/advanced POAG patients were included. ONH blood ?ow acquired by LSFG, circumpapillary vessel density (cpVD, a 250 μm-wide elliptical annulus around the optic disc), and intra-papillary vessel density (ipVD, a 1.5×1.5 mm scan ?eld) acquired by OCTA were measured. Their values were compared among normal controls and patients at each stage of glaucoma using one-way ANOVA, and the correlation between measurements obtained by the two methods was examined by univariate regression analysis. Results: ONH tissue blood ?ow, tissue mean blur rate (MBR-T), and cpVD in the outer layer of the retina signi?cantly decreased with the progression of glaucoma stage, although the latter showed no signi?cant difference between normal subjects and mild-stage glaucoma patients. MBR-T was signi?cantly correlated with cpVD, but not with ipVD, in the retinal outer layer. Conclusion: A correlation was found only between MBR-T and cpVD in the retinal outer layer. A difference in MBR-T, but not in cpVD, was detected between normal controls and mild glaucoma patients.
关键词： optic nerve head,blood ?ow,laser speckle ?owgraphy,optical coherent tomography angiography
更新于2025-09-16 10:30:52
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Evaluation of blood flow on optic nerve head after pattern scan and conventional laser panretinal photocoagulation
摘要： To evaluate the changes in the blood ?ow on retina and the optic nerve head (ONH) after conventional laser treatment and to compare it to that after patterned scanning laser (PASCAL) treatment in patients with severe nonproliferative diabetic retinopathy (S-NPDR). In this prospective, cross-sectional study, the blood ?ow on retina and the ONH was assessed by laser speckle ?owgraphy using the mean blur rate (MBR) in 39 eyes with S-NPDR before, 1, 4, 8, 12 weeks after panretinal photocoagulation (PRP). Of 39 eyes, 17eyes with 17 patients treated by conventional laser and 22 eyes with 22 patients treated by PASCAL. The mean age was 55.5 ± 11.5 years in the conventional laser group, 55.6 ± 11.8 years in the PASCAL group. The MBR-vessel, which can be dominantly expressed as retinal blood ?ow, was signi?cantly reduced after PRP treated by conventional laser (P < .001), but did not change after PRP treated by PASCAL. The ratio of MBR-vessel to the baseline was signi?cantly lower in the conventional laser group only at Week 1 (P = .045). The MBR-tissue, which can be dominantly expressed as the ONH blood ?ow, did not signi?cantly change after PRP in the both group. The multiple stepwise regression analysis revealed that the laser burns was an independent factor signi?cantly correlated with the ratio of MBR-vessel at Week 1 to the baseline (b = (cid:1)0.550, P = .012). The retinal blood ?ow was signi?cantly reduced during the 12 weeks only after completion of PRP by conventional laser treatment. Our results indicate that short pulse on PRP treatment performed by the PASCAL would not signi?cantly reduce the retinal blood ?ow.
关键词： laser speckle ?owgraphy,patterned scanning laser,panretinal photocoagulation,mean blur rate,retinal blood ?ow
更新于2025-09-12 10:27:22
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Differences in Optic Nerve Head Blood Flow Regulation in Normal Tension Glaucoma Patients and Healthy Controls as Assessed With Laser Speckle Flowgraphy During the Water Drinking Test
摘要： Précis: Optic nerve head (ONH) perfusion was not signi?cantly altered in subjects with normal tension glaucoma (NTG) nor in healthy individuals after performing the water drinking test (WDT), because of its limited effect on ocular perfusion pressure (OPP). Purpose: ONH blood ?ow can be maintained stable in healthy individuals because of a physiological phenomenon called autoregulation. Impairment of autoregulation has been shown especially under condition of NTG. The purpose of this study was to investigate the ONH blood ?ow autoregulation in patients with NTG by in?uencing the OPP with the WDT. Methods: The study included 9 eyes from 9 white patients with a diagnosis of NTG and 9 eyes from age-matched and sex-matched healthy individuals. In the glaucoma group, the antiglaucomatous therapy was paused 3 weeks before the investigations. Measurements of ONH blood ?ow were performed with laser speckle ?owgraphy. After baseline measurements, individuals ingested 800 mL of water in <5 minutes. Measurements were repeated after 15, 30, and 45 minutes. Results: The water ingestion led to a signi?cant rise in intraocular pressure (P < 0.001) but also mean arterial pressure (P < 0.001) in both groups. This resulted in stable OPP (P = 0.051) with no signi?cant difference between the groups (P = 0.43). ONH blood ?ow remained stable over time in both groups (P = 0.719). No signi?cant interaction of time and group was shown for all parameters. Conclusions: Our ?ndings show that the WDT does not signi?cantly in?uence the OPP and therefore has to be considered inferior to other methods used to assess blood ?ow autoregulation.
关键词： laser speckle ?owgraphy,normal tension glaucoma,water drinking test,blood ?ow regulation
更新于2025-09-12 10:27:22
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Changes in the Blood Flow of the Optic Nerve Head Induced by Different Concentrations of Epinephrine in Intravitreal Infusion During Vitreous Surgery
摘要： PURPOSE. We investigated whether intravitreal infusion solution containing epinephrine affects optic nerve head (ONH) blood ?ow during vitreous surgeries. METHODS. The subjects were 22 patients with epimacular membrane or idiopathic macular hole. During vitreous surgery, ONH blood ?ow was examined before and 10 minutes after intravitreal infusion of solution containing epinephrine, via a laser speckle ?owgraphy (LSFG) technique modi?ed for acquiring measurements in a supine position. Epinephrine concentration was set at 1.0 mg/500 mL (1:500,000) or 0.5 mg/500 mL (1:1,000,000), with each concentration assigned to 11 consecutive patients. Relative pupil diameter, IOP, blood pressure, and pulse rate also were measured. RESULTS. A signi?cant reduction in blood ?ow throughout the ONH was induced by intravitreal infusion of epinephrine at 1:500,000, but not at 1:1,000,000. Blood ?ow in ONH tissue was diminished at both concentrations, while that in vessels of the ONH was not altered signi?cantly by either concentration. Both epinephrine concentrations induced signi?cant pupillary dilatation, but no signi?cant changes in IOP, blood pressure, or pulse rate. CONCLUSIONS. This study suggests that epinephrine, used in combination with intravitreal infusion solution, may decrease ONH blood ?ow during vitreous surgeries, as indicated by measurements obtained via a modi?ed LSFG technique. Attention must be paid to the effects of intravitreal infusion of epinephrine on ocular circulation, particularly ONH blood ?ow.
关键词： laser speckle ?owgraphy,optic nerve head,epinephrine,supine position,blood ?ow,vitreous surgery
更新于2025-09-09 09:28:46
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Pulse Waveform Changes in Macular Choroidal Hemodynamics With Regression of Acute Central Serous Chorioretinopathy
摘要： PURPOSE. To quantitatively evaluate the pulse waveform changes in macular choroidal blood ?ow by using laser speckle ?owgraphy (LSFG) with regression of acute central serous chorioretinopathy (CSC). METHODS. This retrospective observational case series included 20 eyes of 20 patients with acute CSC. Laser speckle ?owgraphy was performed at baseline and after 6 months. On the LSFG monochrome map, automatically divided 5 3 5 grid segments within the macula were classi?ed into predominantly delayed ?lling (PDF) or minimally or no delayed ?lling (MDF) areas according to the degree of choroidal ?lling delay on early-phase indocyanine green angiography. The average mean blur rate (MBR) and the pulse waveform parameters, including the skew and blowout time (BOT), were compared between the total PDF and MDF areas during follow-up. RESULTS. The average MBR signi?cantly decreased in both PDF (P ? 0.005) and MDF (P < 0.001) areas during follow-up; in both areas, the skew decreased (P < 0.001 and P ? 0.006, respectively) and BOT increased (P < 0.001 for each), showing signi?cant reduction in vascular resistance at 6 months. The degree of the changes in the skew and BOT was signi?cantly larger (P ? 0.02 and P < 0.001, respectively) in the PDF area than in the MDF area. CONCLUSIONS. Changes in the skew and BOT, indices for vascular resistance, con?rmed the involvement of circulatory disturbance at the acute stage of CSC. The present ?ndings suggested that the pathogenesis of CSC stems from imbalanced distribution of choroidal blood ?ow due to augmented vascular resistance.
关键词： central serous chorioretinopathy,pulse waveform,skew,blowout time,mean blur rate,laser speckle ?owgraphy,choroidal blood ?ow velocity
更新于2025-09-04 15:30:14