Changes in pulse waveforms in response to intraocular pressure elevation determined by laser speckle flowgraphy in healthy subjects

Iwase, C.; Iwase, Takeshi; Tomita, Ryo; Akahori, Tomohiko; Yamamoto, Kentaro; Ra, Eimei; Terasaki, Hiroko

doi:10.1186/s12886-021-02070-7

Cited by 4 publications

(4 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The optimal parameter to use in analyses is not yet known, although it should be noted that results were very similar whether using BOM (analogous to the hemodynamic pulsatility index) or RI (analogous to the hemodynamic resistance index). It has been reported that elevating IOP using an ophthalmodynamometer decreased BOS and increased RI but did not alter RR, 58 although it should be noted that adjusting for average IOP did not alter the statistical significance of any of the main results in our study. The participants were under clinical management at the discretion of the patient's clinician, so animal models in which relevant variables can be directly controlled may aid our understanding of the contribution of vessel stiffness to the true natural history of the disease.…”

Section: Discussioncontrasting

confidence: 67%

“…IOP can affect some LSFG measurements. 58 In multivariable models, higher average IOP significantly modulated predictions of the rate of functional change based on MBR Ave in both tissue and vessels in the “glaucoma suspect” eyes but not in the “glaucoma” eyes (likely because IOP was being managed clinically). However, adjusting for IOP did not significantly alter the relations between the rate of functional change and any of the LSFG parameters related to vascular resistance.…”

Section: Resultsmentioning

confidence: 97%

See 1 more Smart Citation

Retinal Vessel Pulsatile Characteristics Associated With Vascular Stiffness Can Predict the Rate of Functional Progression in Glaucoma Suspects

Gardiner

Cull

Fortune

2023

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

Purpose Tissue stiffening and alterations in retinal blood flow have both been suggested as causative mechanisms of glaucomatous damage. We tested the hypothesis that retinal blood vessels also stiffen, using laser speckle flowgraphy (LSFG) to characterize vascular resistance. Methods In the longitudinal Portland Progression Project, 231 eyes of 124 subjects received LSFG scans of the optic nerve head (ONH) and automated perimetry every 6 months for six visits. Eyes were classified as either “glaucoma suspect” or “glaucoma” eyes based on the presence of functional loss on the first visit. Vascular resistance was quantified using the mean values of several instrument-defined parameterizations of the pulsatile waveform measured by LSFG, either in major vessels within the ONH (serving the retina) or in capillaries within ONH tissue, and age-adjusted using a separate group of 127 healthy eyes of 63 individuals. Parameters were compared against the severity and rate of change of functional loss using mean deviation (MD) over the six visits, within the two groups. Results Among 118 “glaucoma suspect” eyes (average MD, −0.4 dB; rate, −0.45 dB/y), higher vascular resistance was related to faster functional loss, but not current severity of loss. Parameters measured in major vessels were stronger predictors of rate than parameters measured in tissue. Among 113 “glaucoma” eyes (average MD, −4.3 dB; rate, −0.53 dB/y), higher vascular resistance was related to more severe current loss but not rate of loss. Conclusions Higher retinal vascular resistance and, by likely implication, stiffer retinal vessels were associated with more rapid functional loss in eyes without significant existing loss at baseline.

show abstract

Section: Discussioncontrasting

confidence: 67%

Section: Resultsmentioning

confidence: 97%

Retinal Vessel Pulsatile Characteristics Associated With Vascular Stiffness Can Predict the Rate of Functional Progression in Glaucoma Suspects

Gardiner

Cull

Fortune

2023

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

show abstract

“…Hence, no direct comparisons to cohorts with elder and female patients are possible. However, in a healthy eye, retinal perfusion remains similar during the day and usually also within different days of measurement [12,22,23].…”

Section: Discussionmentioning

confidence: 99%

Analysis of Blood Flow in the Macula and Optic Nerve Head in Healthy Young Volunteers Using Laser Speckle Flowgraphy

Bajka

Foa

Sidhu

et al. 2023

Klin Monbl Augenheilkd

View full text Add to dashboard Cite

Purpose To assess optic nerve head (ONH) and macular blood flow in young healthy volunteers using laser speckle flowgraphy (LSFG). Methods This is a prospective single-center study conducted at the Department of Ophthalmology, University Hospital Zurich from May to November 2021. Young, healthy men aged ≥ 18 years without ocular or systemic diseases were included. A corrected visual acuity (VA) of 0.0 logMAR or better in both eyes and an intraocular pressure (IOP) of 21 mmHg or lower were required for inclusion. Subjects exceeding a spherical equivalent (SE) of ± 6 diopters (dpt) were excluded. Blood flow in the macula and the ONH was recorded using the Nidek LSFG RetFlow device (Nidek Company, Ltd., Hirioshi-cho, Japan). Laser power was set to 0.5 Millivolts (mV). Mean blur rate (MBR) was recorded as a parameter for blood flow. MBR is a calculated parameter that represents relative blood flow velocity correlated with the real anatomical blood flow rate. Colored heat maps of the recorded retinal area were generated automatically by the RetFlow device. Results Final analyses included 83 eyes of 43 male volunteers. Mean age was 21.9 years (SD ± 1.5, range: 20 to 29). Mean corrected VA was − 0.1 logMAR (SD ± 0.05, range: − 0.2 to 0.0), mean IOP was 15.4 mmHg (SD ± 2.5, range: 8.5 to 18.5), and mean SE was − 0.3 dpt (SD ± 1.2, range: − 5.0 to 1.2). Mean ONH MBR was 37.44 (SD ± 7.9, range: 22.5 to 53.5) and mean macular MBR was 27.8 (SD ± 9.7, range: 6.4 to 57.7). Pearsonʼs Test showed a strong correlation between macular and papillary blood flow (p < 0.05, coefficient: 0.647). Conclusion This study provides both ONH and macular blood flow data in a healthy young male population, showing a strong correlation between ONH and macular blood flow in the examined eyes. Further investigations are required to assess the validity of MBR as a parameter for the combined evaluation of retinal blood flow at the macula and ONH in healthy volunteers and patients with various diseases.

show abstract

“…We also found that IOP and MAP were associated with FAI-T in the overall group of patients and the female patients. Iwase et al demonstrated that FAI in the ONH significantly increased with increasing IOP in healthy subjects [51]. In addition, Yanagida et al showed that FAI in the overall ONH was negatively associated with MAP [40].…”

Section: Pulse Waveform In the Onh And Antioxidant Capacity In Glaucomamentioning

confidence: 99%

Sex differences in the association between systemic oxidative stress status and optic nerve head blood flow in normal-tension glaucoma

et al. 2023

View full text Add to dashboard Cite

Purpose To investigate the association of systemic oxidative stress markers and optic nerve head (ONH) blood flow in normal-tension glaucoma (NTG) patients, as well as sex differences in this association. Methods This was a cross-sectional study of 235 eyes with NTG of 134 patients (56 male, 78 female; mean age, 60.9±14.1 years). Laser speckle flowgraphy (LSFG) was used to measure ONH blood flow (mean blur rate in the tissue area of the ONH; MBR-T) and LSFG pulse-waveform parameters, including flow acceleration index in the tissue area of the ONH (FAI-T). Oxidative stress markers, diacron-reactive oxygen metabolites (d-ROMs), and biological antioxidant potential (BAP) were measured with a free radical elective evaluator. Spearman’s rank correlation test and a multivariate linear mixed-effect model were used to investigate factors associated with ONH blood flow. Results MBR-T was significantly correlated with age (rs = -0.28, p < 0.001), mean arterial pressure (rs = -0.20, p = 0.002), intraocular pressure (rs = 0.24, p < 0.001), peripapillary retinal nerve fiber layer thickness (rs = 0.62, p < 0.001), and disc area (rs = -0.26, p < 0.001), but not with serum d-ROM level. Separate analyses of the subjects divided by sex showed that BAP was positively correlated to MBR-T (rs = 0.21, p = 0.036) and FAI-T (rs = 0.36, p < 0.001) only in male subjects. Similarly, BAP was significantly associated with MBR-T (β = 0.25, p = 0.026) and FAI-T (β = 0.37, p < 0.001) in male subjects in a multivariate linear mixed-effect model. Conclusion A lower serum antioxidant level, as indicated by BAP, was associated with reduced ONH blood flow only in male NTG patients. Our findings suggest that there are sex differences in the involvement of oxidative stress in the pathogenesis of reduced ocular blood flow in NTG.

show abstract

Changes in pulse waveforms in response to intraocular pressure elevation determined by laser speckle flowgraphy in healthy subjects

Cited by 4 publications

References 41 publications

Retinal Vessel Pulsatile Characteristics Associated With Vascular Stiffness Can Predict the Rate of Functional Progression in Glaucoma Suspects

Retinal Vessel Pulsatile Characteristics Associated With Vascular Stiffness Can Predict the Rate of Functional Progression in Glaucoma Suspects

Analysis of Blood Flow in the Macula and Optic Nerve Head in Healthy Young Volunteers Using Laser Speckle Flowgraphy

Sex differences in the association between systemic oxidative stress status and optic nerve head blood flow in normal-tension glaucoma

Contact Info

Product

Resources

About