Laser Speckle and Hydrogen Gas Clearance Measurements of Optic Nerve Circulation in Albino and Pigmented Rabbits With or Without Optic Disc Atrophy

Aizawa, Naoko; Nitta, Fumihiko; Kunikata, Hiroshi; Sugiyama, Tetsuya; Ikeda, Tsunehiko; Araie, Makoto; Nakazawa, Toru

doi:10.1167/iovs.14-15373

Cited by 84 publications

(72 citation statements)

References 18 publications

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“…We found that MBR data pooled from the albino and pigmented rabbits, with or without ET-1 treatment in both the intravenous and intravitreal groups, were highly correlated with capillary blood flow (r = 0.87, P < 0.001, n = 45), with no significant intergroup differences (P = 0.138) in the relationship between MBR and capillary blood flow. 55 The demonstration that MBR can be used in interindividual comparisons represents an important advancement, reinforced by our finding that in glaucomatous eyes, MBR decreases significantly in a stage-dependent manner. 8 We also found that MBR was highly correlated with cpRNFLT and Humphrey field analyzer-measured mean deviation.…”

Section: Laser Speckle Flowgraphymentioning

confidence: 88%

“…We, in addition to another group, have found that the intravitreous and intravenous administration of ET-1 decreases ONH blood flow in rabbits. 55 Furthermore, the intravitreal administration of ET-1 induced the formation of cupping in the ONH. These findings suggest that ET-1-induced decreases in OBF are associated with ONH cupping and that ET-1 may be a key molecule in OBF decreases, along with an inadequate OBF response, in patients with glaucoma.…”

Section: Endothelinmentioning

confidence: 99%

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Ocular Blood Flow and Influencing Factors for Glaucoma

Nakazawa

2016

Asia-Pacific Journal of Ophthalmology

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Open-angle glaucoma (OAG) is characterized by optic nerve fiber atrophy and deterioration of the visual field, corresponding to damage to the optic nerve head. Intraocular pressure (IOP) is currently the only evidence-based, treatable risk factor for OAG. However, normal-tension glaucoma, the most common type of OAG in Asia, is a type of glaucoma with an unclear pathogenesis. Glaucoma is suspected to be a multifactorial disease with IOP-dependent and IOP-independent risk factors, including decreased ocular blood flow (OBF), oxidative stress, decreased axoplasmic flow, and genetic background. A number of epidemiological studies have generated strong evidence that OBF may be an especially important risk factor for the progression of glaucoma. Recent innovations in laser speckle flowgraphy and optical coherence tomography-based angiography have allowed us to noninvasively monitor changes in the microcirculation of the optic nerve head with high reproducibility. Laser speckle flowgraphy-derived measurement parameters include mean blur rate and pulse wave form parameters, whereas the main optical coherence tomography angiography-derived parameter is the vessel index. Decreases in these parameters are associated with the severity of glaucomatous damage, and changes are detectible even in the earliest, preperimetric stage of glaucoma. In the future, OBF analysis may improve significantly because of continuing progress in the development of the relevant instruments. This review will summarize possible connections between systemic and OBF abnormalities and OAG, describe the scientific rationale for these connections, and discuss their potential implications. Thus, this review will summarize the role of OBF in glaucoma pathogenesis and discuss the wide range of IOP-independent risk factors.

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Section: Laser Speckle Flowgraphymentioning

confidence: 88%

Section: Endothelinmentioning

confidence: 99%

Ocular Blood Flow and Influencing Factors for Glaucoma

Nakazawa

2016

Asia-Pacific Journal of Ophthalmology

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“…LSFG enables non-invasive, patient- and examiner-friendly quantitative estimation of perfusion at the ONH, retina and choroid, simultaneously, in less than 5 seconds. Validation of the technique for the measurement of ONH perfusion has been established by means of direct comparison with the hydrogen gas clearance method [11,12] and the microsphere method. [13] LSFG has helped add to the understanding of perfusion status and its role in the pathophysiology of numerous ocular diseases.…”

Section: Introductionmentioning

confidence: 99%

Ocular Blood Flow Measurements in Healthy White Subjects Using Laser Speckle Flowgraphy

et al. 2016

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PurposeTo assess the feasibility and reliability of Laser Speckle Flowgraphy (LSFG) to measure ocular perfusion in a sample of healthy white subjects and to elucidate the age-dependence of the parameters obtained.MethodsThis cross-sectional study included 80 eyes of 80 healthy, non-smoking white subjects of Western European descent between 19 and 79 years of age. A commercial LSFG instrument was applied to measure ocular blood flow at the optic nerve head (ONH) three successive times before and after pharmacological pupil dilation. The mean blur rate (MBR), a measure of relative blood flow velocity, was obtained for different regions of the ONH. Eight parameters of ocular perfusion derived from the pulse-waveform analysis of MBR including blowout time (BOT) and falling rate (FR) were also recorded.ResultsArtifact-free LSFG images meeting the quality criteria for automated image analysis were obtainable in 93.8% without pupil dilation and in 98.8% with pharmacological pupil dilation. Measurements of MBR showed excellent repeatability with intraclass correlation coefficients ≥ 0.937 and were barely affected by pupil dilation. The majority of pulse-waveform derived variables exhibited equally high repeatability. MBR-related blood flow indices exhibited significant age dependence (p<0.001). FR (r = 0.747, p<0.001) and BOT (r = -0.714, p<0.001) most strongly correlated with age.ConclusionsLSFG represents a reliable method for the quantitative assessment of ocular blood flow in white subjects. Our data affirms that the LSFG-derived variables FR and BOT may be useful biomarkers for age-related changes in ocular perfusion.

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“…In addition, our recent studies suggested that absolute MBR values for the ONH correlated with CBF, indicating the quantifiability of these values in the absence of large topographical and color differences in the ONH [31,33] . This condition was probably observed in the present study because we compared MBR values among eyes with myopic ONHs, which have similar topographical and color appearances.…”

Section: Discussionmentioning

confidence: 86%

Clinical Usefulness of the Measurement of Optic Nerve Head Blood Flow in Myopic Normal-Tension Glaucoma

Sugiyama¹,

Nakamura²,

Shimizu³

et al. 2015

International Journal of Ophthalmic Research

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Laser Speckle and Hydrogen Gas Clearance Measurements of Optic Nerve Circulation in Albino and Pigmented Rabbits With or Without Optic Disc Atrophy

Abstract: Regardless of the presence of fundus pigmentation or ONH atrophy, ONH MBR and ONH CBF were highly correlated, suggesting that MBR in the ONH tissue is usable for interindividual and intergroup comparisons.

Cited by 84 publications

References 18 publications

Ocular Blood Flow and Influencing Factors for Glaucoma

Ocular Blood Flow and Influencing Factors for Glaucoma

Ocular Blood Flow Measurements in Healthy White Subjects Using Laser Speckle Flowgraphy

Clinical Usefulness of the Measurement of Optic Nerve Head Blood Flow in Myopic Normal-Tension Glaucoma

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