Effet de l’adaptation à l’obscurité sur le flux rétinien1

Riva, Charles E.; Logean, Eric; Petrig, Benno L.; Falsini, Benedetto

doi:10.1055/s-2000-10990

Cited by 23 publications

(14 citation statements)

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“…One would not then expect a change in retinal blood flow between darkness and steady light, which was supported by results with an infrared laser Doppler method in humans. Riva et al (Riva et al, 2000) found a transient increase in retinal blood flow at the onset of light, but no maintained change, and suggested that previous measurements (Feke et al, 1983; Riva et al, 1983) that found a dark-light difference were probably influenced by this transition. However, nearly simultaneously with the more recent study by Riva et al, Havelius et al (Havelius et al, 1999), using an ultrasound (color Doppler) method in humans, reported a modest increase in central retinal artery velocity of about 20% during 25 min of darkness relative to steady light (120 to 1350 lux).…”

Section: Fundamentals Of O2 Supply To the Retinamentioning

confidence: 87%

“…Under steady state conditions, previous studies have shown no major difference in metabolism in the inner retina between light- and dark-adapted eyes, although as discussed in section 3.2.1, there may be a small change in blood flow (Braun et al, 1995; Riva et al, 2000). To induce substantial retinal hemodynamic alterations, however, strong flickering light for at least 30 seconds is employed (Mishra et al, 2011).…”

Section: Approaches To Retinal Oxygenmentioning

confidence: 92%

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Retinal oxygen: from animals to humans

Linsenmeier

Zhang

2017

Progress in Retinal and Eye Research

192

150

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This article discusses retinal oxygenation and retinal metabolism by focusing on measurements made with two of the principal methods used to study O2 in the retina: measurements of PO2 with oxygen-sensitive microelectrodes in vivo in animals with a retinal circulation similar to that of humans, and oximetry, which can be used non-invasively in both animals and humans to measure O2 concentration in retinal vessels. Microelectrodes uniquely have high spatial resolution, allowing the mapping of PO2 in detail, and when combined with mathematical models of diffusion and consumption, they provide information about retinal metabolism. Mathematical models, grounded in experiments, can also be used to simulate situations that are not amenable to experimental study. New methods of oximetry, particularly photoacoustic ophthalmoscopy and visible light optical coherence tomography, provide depth-resolved methods that can separate signals from blood vessels and surrounding tissues, and can be combined with blood flow measures to determine metabolic rate. We discuss the effects on retinal oxygenation of illumination, hypoxia and hyperoxia, and describe retinal oxygenation in diabetes, retinal detachment, arterial occlusion, and macular degeneration. We explain how the metabolic measurements obtained from microelectrodes and imaging are different, and how they need to be brought together in the future. Finally, we argue for revisiting the clinical use of hyperoxia in ophthalmology, particularly in retinal arterial occlusions and retinal detachment, based on animal research and diffusion theory.

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Section: Fundamentals Of O2 Supply To the Retinamentioning

confidence: 87%

Section: Approaches To Retinal Oxygenmentioning

confidence: 92%

Retinal oxygen: from animals to humans

Linsenmeier

Zhang

2017

Progress in Retinal and Eye Research

192

150

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“…However, this unavoidable transition from dark-to-light conditions during fundus photography seems in itself to cause rapid changes in the retinal blood flow. 11,14 A major advantage of our examination technique is that the fundus imaging was made using near-infrared light, eliminating the effects of rapid dark-light changes that occur during normal photography. Further, the analysis of the recordings made with the RVA allowed us to achieve accurate results by averaging the periodic changes of vessel diameter (e.g., pulse waves) using 1500 to 2000 measurements made over a period of 3 minutes.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, they could not actually measure in darkness, only before and after dark adaptation. Later, Riva et al 11,14 adapted their method and used near-infrared laser Doppler flowmetry to measure the flow velocities in retinal branch vessels during dark adaptation. Using this new method they did not find significantly increased flow velocity in the dark-adapted retinal vessels.…”

Section: Discussionmentioning

confidence: 99%

The Diameters of the Human Retinal Branch Vessels Do Not Change in Darkness

Barcsay

Seres

Németh

2003

Invest. Ophthalmol. Vis. Sci.

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“…Light exposure following dark adaptation seems to induce a rapid transient increase in the retinal blood flow velocity, reaching peak value at 30–60 seconds (Riva et al. 2000 ). The study of Feke et al.…”

Section: Discussionmentioning

confidence: 99%

Retinal vascular calibre and response to light exposure and serial imaging

Hanno

Sjølie

Mathiesen

2013

Acta Ophthalmologica

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PurposeTo investigate whether retinal vessel calibre measurements on optical retinal photography are affected by light and dark exposure prior to photography and whether the vessel calibre changes during an imaging sequence of several images.MethodsDigital optical retinal photographs were obtained from 32 healthy adults in two separate image sequences of six images during 1 min; one sequence with 10 min of dark exposure and one with 10 min of light exposure prior to imaging. Retinal arteriolar and venular calibres were measured computer-assisted and summarized as central retinal artery and vein equivalents (CRAE and CRVE). Outcome measures were difference in calibres after prior light versus prior dark exposure and difference in calibre during each of the two imaging sequences.ResultsCRVE was wider with prior light exposure (2.7%, p = 0.0001), comparing the first image in each image sequence. Within each sequence, there was a venular dilatation from first to last image, both with prior light exposure (1.7%, p = 0.0003) and prior dark exposure (3.1%, p < 0.0001), with the change less pronounced with prior light exposure (p = 0.0164). CRAE showed no significant change in either outcome.ConclusionsRetinal venular calibre was wider with light exposure prior to imaging and increased slightly during the imaging sequences, less pronounced after prior light than dark exposure. Measurement error due to these effects will probably be reduced by avoiding dark prior to imaging, and a possible bias effect of endothelial dysfunction may possibly be reduced by measuring calibre on an image taken early in the image sequence.

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Effet de l’adaptation à l’obscurité sur le flux rétinien1

Abstract: These results do not support the hypothesis that Fret in normal volunteers is increased during DA. Rather, they strongly suggest that the transient increase in flux observed after DA is induced by the transition from dark to light (FNSRS #3200-043157 et CNR, It. #95.01715.CT04).

Cited by 23 publications

References 0 publications

Retinal oxygen: from animals to humans

Retinal oxygen: from animals to humans

The Diameters of the Human Retinal Branch Vessels Do Not Change in Darkness

Retinal vascular calibre and response to light exposure and serial imaging

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