Non-contact, two-dimensional measurement of tissue circulation in choroid and optic nerve head using laser speckle phenomenon

Tamaki, Yasuhiro; Araie, Makoto; Kawamoto, E; Eguchi, Shuichiro; Fujii, Hitoshi

doi:10.1016/s0014-4835(05)80094-6

Cited by 223 publications

(209 citation statements)

References 23 publications

Supporting

Mentioning

205

Contrasting

Order By: Relevance

“…19,20,23 It allows noncontact and noninvasive two-dimensional measurement of blood velocity in intraocular tissues including the ONH using laser beam and fundus camera. The laser beam (wavelength 808 nm; power 2 mW) was focused on the surface of the ONH in the largest area free of visible vessels (for NB ONH measurement) or on the area of the retina just superior or inferior to the ONH without visible vessels (for NB CH measurement), and the scattered light was imaged on an image sensor where the speckle pattern of the laser appeared.…”

Section: Animal Studiesmentioning

confidence: 99%

“…A 20 ml drop of 5% phenylephrine hydrochloride was instilled into one randomly chosen eye, and physiological saline was instilled into the contralateral eye as a control. IOP and NB ONH in both eyes and the FABPm and pulse rate were measured before and 30, 60, 90, 120, 150, and 180 min after the phenylephrine instillation, as reported previously 19,20,[24][25][26][27][28][29][30] by a masked investigator (JT). PO 2 , PCO 2 , pH, and body temperature were checked before and 90 and 180 min after the instillation.…”

Section: Animal Studiesmentioning

confidence: 99%

“…Because of the difficulties in the identification of the same target area in the choroid, NB CH was measured in one eye of a rabbit anaesthetized and fixed throughout the experiment as described previously. 20,28,[31][32][33] A drop of phenylephrine was instilled unilaterally in eight rabbits, whereas the other eyes were left untreated. IOP and NB CH in the phenylephrine-treated eyes were measured before and 30, 60, 90, 120, 150, and 180 min after the drug instillation, and the other eight rabbits were treated with physiological saline unilaterally and the measurements were carried out in the identical manner as controls.…”

Section: Animal Studiesmentioning

confidence: 99%

“…Then, the positive results in the rabbits prompted us to study the effects of phenylephrine on the ONH and retinal circulation in humans using noninvasive laser methods. [19][20][21][22] …”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Takayama

Mayama

Mishima

et al. 2008

Eye

View full text Add to dashboard Cite

Purpose To investigate the effects of topical phenylephrine on circulation in the optic nerve head (ONH), posterior choroids, or retina in rabbits and healthy humans. Methods Tissue blood velocity in the ONH and posterior choroid was measured using the laser speckle method as normalized blur (NB ONH and NB CH ) in 28 anaesthetized albino rabbits. NB and intraocular pressure (IOP) in both eyes were measured for 180 min after unilateral single instillation of 5% phenylephrine and contralateral physiological saline as a control. In 11 normal volunteers aged 26.0±2.7 years, NB ONH was measured for 180 min after unilateral three drops of 5% phenylephrine and contralateral physiological saline in a double-masked manner. In the other 17 normal volunteers aged 25.5 ± 2.4 years, blood velocity and blood flow in a major branch of the central retinal artery were measured using the laser Doppler blood flow metre and IOP and systemic circulatory parameters were monitored in similar fashion. Analysis of variance was applied for intergroup comparisons.Results NB ONH and NB CH decreased significantly only in the phenylephrinetreated eyes in rabbits by maximum of 9 and 20%, respectively (P ¼ 0.0046 and 0.0009), despite IOP decrease. In humans, NB ONH decreased significant by maximum of 13% (P ¼ 0.0047) and resistive index in the retinal arteries increased by 10% (P ¼ 0.0067) unilaterally; whereas IOP, diameter, blood velocity, or blood flow of the arteries was not significantly changed. Conclusion Topical phenylephrine could exert a significant unfavourable effect on circulation in the ONH, choroidal tissue, and retinal arteries in rabbits and normal young humans.

show abstract

Section: Animal Studiesmentioning

confidence: 99%

Section: Animal Studiesmentioning

confidence: 99%

Section: Animal Studiesmentioning

confidence: 99%

“…Then, the positive results in the rabbits prompted us to study the effects of phenylephrine on the ONH and retinal circulation in humans using noninvasive laser methods. [19][20][21][22] …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Takayama

Mayama

Mishima

et al. 2008

Eye

View full text Add to dashboard Cite

show abstract

“…As an alternative to Laser Doppler flowmetry, LSCI was first introduced for the mapping of microvascular perfusion in various tissues including the skin and the retina (Briers 2001;Ruth 1990;Tamaki et al 1994), and was later adapted and found highly suitable to create flow maps of the superficial layers of cerebral cortex (Dunn et al 2001). LSCI flow maps are computed using fluctuating intensity of the random interference effect known as speckle; still, LSCI and laser Doppler flowmetry both derive flow information on the basis of the same physical phenomenon and yield comparable results (Briers 2001;Tew et al 2011).…”

mentioning

confidence: 99%

Demonstration of impaired neurovascular coupling responses in TG2576 mouse model of Alzheimer’s disease using functional laser speckle contrast imaging

et al. 2017

View full text Add to dashboard Cite

Increasing evidence from epidemiological, clinical, and experimental studies indicates that cerebromicrovascular dysfunction and microcirculatory damage play critical roles in the pathogenesis of many types of dementia in the elderly, including both vascular cognitive impairment (VCI) and Alzheimer's disease. Vascular contributions to cognitive impairment and dementia (VCID) include impairment of neurovascular coupling responses/functional hyperemia (Bneurovascular uncoupling^). Due to the growing interest in understanding and pharmacologically targeting pathophysiological mechanisms of VCID, there is an increasing need for sensitive, easy-to-establish methods to assess neurovascular coupling responses. Laser speckle contrast imaging (LSCI) is a technique that allows rapid and minimally invasive visualization of changes in regional cerebromicrovascular blood perfusion. This type of imaging technique combines high resolution and speed to provide great spatiotemporal accuracy to measure moment-to-moment changes in cerebral blood flow induced by neuronal activation. Here, we provide detailed protocols for the successful measurement in neurovascular coupling responses in anesthetized mice equipped with a thinned-skull cranial window using LSCI. This method can be used to evaluate the effects of anti-aging or anti-AD treatments on cerebromicrovascular health.Keywords Neurovascular coupling . Functional hyperemia . Laser speckle contrast imaging . Laser speckle contrast analysis . LASCA . Laser speckle imaging . LSI Neurovascular uncoupling in aging and Alzheimer's diseaseIt is well recognized that the brain consumes more energy than any other human organ. Over 20% of the body's total energy requirements are spent to fuel the brain, which in turn only accounts for 2% of the total body mass. Moment-to-moment regulation of cerebral blood flow (CBF) is crucial since inadequate supply of glucose and oxygen to an active region of the brain GeroScience (2017) 39:465-473

show abstract

Effect of Brimonidine Tartrate on Ocular Hemodynamic Measurements

Lachkar

Migdal²,

Dhanjil³

1998

Arch Ophthalmol

View full text Add to dashboard Cite

To study the effect of a selective ␣ 2adrenoreceptor agonist, brimonidine tartrate, on ocular hemodynamics. Subjects and Methods: Eighteen patients with ocular hypertension were enrolled in a prospective, randomized, double-masked study in which 0.2% brimonidine tartrate, administered twice daily, was compared with its vehicle in a crossover fashion. The effect on the ocular circulation was assessedbycolorDopplerultrasound,whichmeasuredblood flow velocities (peak systolic and end diastolic velocities) in the central retinal, ophthalmic, nasal, and temporal ciliary arteries. The following tests were performed at 2 weekly intervals on both treatments, 0.2% brimonidine tartrate and the placebo: intraocular pressure, heart rate, blood pressure, and color Doppler ultrasound. Results: Velocities and resistivity indices measured by color Doppler ultrasound in the ophthalmic artery, central retinal artery, nasal artery, and temporal ciliary arteries showed no statistically significant differences between the placebo and 0.2% brimonidine tartrate when compared with baseline values and between the groups. Intraocular pressure was decreased by 17.7% ± 9.5% with 0.2% brimonidine tartrate (vs 9% ± 8% with placebo). Conclusion: The hemodynamics of the posterior segment of the eye as measured by color Doppler ultrasound do not appear to be altered by 2% brimonidine tartrate.

show abstract

Non-contact, two-dimensional measurement of tissue circulation in choroid and optic nerve head using laser speckle phenomenon

Cited by 223 publications

References 23 publications

Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Topical phenylephrine decreases blood velocity in the optic nerve head and increases resistive index in the retinal arteries

Demonstration of impaired neurovascular coupling responses in TG2576 mouse model of Alzheimer’s disease using functional laser speckle contrast imaging

Effect of Brimonidine Tartrate on Ocular Hemodynamic Measurements

Contact Info

Product

Resources

About