Laser Doppler flowmetry in the optic nerve

Riva, Charles E.; Harino, Seiyo; Petrig, Benno L.; Shonat, Ross D.

doi:10.1016/0014-4835(92)90123-a

Cited by 205 publications

(128 citation statements)

References 11 publications

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“…At the conclusion of the experiments the animal was killed by administration of 5 ml pentobarbitone (360 mg mlF1) while still under general anaesthesia. Blood flow recording Recording of blood flow at the optic nerve was performed by a laser Doppler fundus-camera-based flowmeter, placed approximately 5 cm in front of the eye, using a near-infrared 810 nm diode laser as a probing source and a silicon avalanche photodiode as a detector (Riva, Harino, Petrig & Shonat, 1992 (Borgos, 1990;Nilsson, 1990) and the result was plotted on a chart recorder. The time constants of these instruments were 3 and 5 s, respectively.…”

Section: Methods Preparationmentioning

confidence: 99%

Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

Toi

Riva

1995

The Journal of Physiology

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1. The present investigation explored, in thirty‐four anaesthetized cats, the blood flow changes at the optic nerve head elicited by sinusoidally modulated photic stimuli. 2. The stimuli were achromatic, diffuse and had 30 deg diameter field size; the stimulus frequency was varied from 0 to 100 Hz, modulation depth from 0 to 100% and mean retinal illuminance up to 50,000 trolands (td); the blood flow was measured with a near‐infrared (810 nm) laser Doppler flowmeter. 3. At various frequencies, modulation depths and mean retinal illuminance, sinusoidal flicker stimulation always caused an increase in blood flow at the optic nerve head relative to steady stimulation. 4. The frequency response and temporal contrast sensitivity function of the blood flow changes had a bandpass shape; the high‐frequency slope of the frequency response was 3 decades (dec) per decade and that of the temporal contrast sensitivity function was 1.7 dec per dec, close to the slope for cat ‘on’ ganglion cells (2.6 dec per dec). 5. In most cats, the magnitude of the increase in blood flow was a sigmoidal function of modulation depth; in the remainder, the relationship was close to linear. 6. The threshold of blood flow changes varied with respect to mean retinal illuminance similar to Ferry‐Porter's law and the photopic linear slope was 50 Hz dec‐1. 7. In comparison with reported psychophysical and electrophysiological responses elicited by similar stimulations, the results of the present study resemble more those obtained from ganglion cells than those from electroretinograms, visual‐evoked potentials and psychophysics. It is suggested that the blood flow changes at the optic nerve head are induced by the activity of ganglion cells.

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Section: Methods Preparationmentioning

confidence: 99%

Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

Toi

Riva

1995

The Journal of Physiology

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“…Definition of the sites of fundus pulsation measurements in the optic disc. Points [1][2][3][4] were located at the neuroretinal rim, points [5][6][7][8] were located at the cup.…”

Section: Experimental Designmentioning

confidence: 99%

A comparison between laser interferometric measurement of fundus pulsation and pneumotonometric measurement of pulsatile ocular blood flow 1. Baseline considerations

Schmetterer

Dallinger

Findl

et al. 2000

Eye

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“…12,13 With this technique, the vascularized tissue is illuminated by coherent laser light. Light scattered by the moving red blood cells undergoes a frequency shift.…”

mentioning

confidence: 99%

Regulation of Optic Nerve Head Blood Flow during Combined Changes in Intraocular Pressure and Arterial Blood Pressure

Boltz

Schmidl

Werkmeister

et al. 2013

J Cereb Blood Flow Metab

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In the choroid, there is evidence that blood flow does not only depend on ocular perfusion pressure (OPP), but also on absolute mean arterial pressure (MAP) and intraocular pressure (IOP). The present study included 40 healthy subjects to investigate whether such behavior is also found in the optic nerve head (ONH). The ONH blood flow (ONHBF) was studied using laser Doppler flowmetry during a separate increase in IOP and MAP as well as during a combined elevation. Mean arterial pressure was increased by isometric exercise and IOP by the suction method. During both, the change in ONHBF was less pronounced than the change in OPP indicating autoregulation. Correlation analysis was performed for the combined experiments after pooling all data according to IOP and MAP values. A correlation between ONHBF and MAP was found at IOPs p25 mm Hg (Po0.001), but not at IOPs425 mm Hg (P ¼ 0.79). Optic nerve head blood flow and IOP were significantly correlated (Po0.001), and ONHBF was only slightly dependent on MAP. The data of the present study indicate a complex regulation of ONHBF during combined changes in MAP and IOP. Our results may be compatible with myogenic mechanisms underlying autoregulation, and indicate better ONHBF regulation during an increase in MAP than during an increase in IOP.

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Laser Doppler flowmetry in the optic nerve

Cited by 205 publications

References 11 publications

Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

A comparison between laser interferometric measurement of fundus pulsation and pneumotonometric measurement of pulsatile ocular blood flow 1. Baseline considerations

Regulation of Optic Nerve Head Blood Flow during Combined Changes in Intraocular Pressure and Arterial Blood Pressure

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