The intensity of the light reflex on retinal arteries and veins

Brinchmann‐Hansen, Olaf; Sandvik, Leiv

doi:10.1111/j.1755-3768.1986.tb06971.x

Cited by 14 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Enhancement of the arteriolar light reflex could reflect either arteriolar wall thickening or changes in blood flow velocity. 15 There are no other relevant studies for comparison with our study. Findings from this study demonstrate patients with deep ICH were more likely to have qualitative and quantitative retinal arteriolar wall signs, consistent with hypertensive damage to small vessels, but not retinopathy lesions, compared to patients with nonlacunar infarction.…”

Section: Discussionmentioning

confidence: 83%

Retinal Microvascular Signs May Provide Clues to the Underlying Vasculopathy in Patients With Deep Intracerebral Hemorrhage

Baker

Hand²,

Liew³

et al. 2010

Stroke

View full text Add to dashboard Cite

Background and Purpose-Deep intracerebral hemorrhage (ICH) and lacunar infarcts are the result of small vessel disease, whereas nonlacunar infarcts are often caused by large artery atherosclerosis or cardiac embolism. We hypothesized that patients with deep ICH and lacunar infarcts have similar retinal microvascular signs and that these differ from those seen in patients with nonlacunar infarcts. Methods-We studied patients with acute stroke and classified their stroke as deep ICH, lacunar infarction, or nonlacunar infarction. In a masked fashion we assessed retinal photographs for quantitative and qualitative evidence of microvascular damage. Results-We recruited 630 patients (51 had deep ICH, 93 had lacunar infarction, and 486 had nonlacunar infarction).Patients with deep ICH were more likely than those with nonlacunar infarcts to have severe focal narrowing of the retinal arterioles (OR, 3.7), severe arteriovenous nicking (OR, 2.6), and quantitatively narrower retinal arterioles and wider retinal venules. Retinal microvascular signs were similar in patients with deep ICH and lacunar infarction. Conclusions-Patients

show abstract

Section: Discussionmentioning

confidence: 83%

Retinal Microvascular Signs May Provide Clues to the Underlying Vasculopathy in Patients With Deep Intracerebral Hemorrhage

Baker

Hand²,

Liew³

et al. 2010

Stroke

View full text Add to dashboard Cite

show abstract

“…Assessment of this arteriovenous ratio (AVR), the ratio of arteriolar diameter to venule diameter, and the general appearance of retinal vessels are based on the normal light reflex of the retinal vasculature, which is formed by the reflection from the interface between the blood column and the vessel wall. 4,5 In the thin-walled veins, the strong absorbance of green light by hemoglobin leads to the characteristic dark appearance. 6 Retinal arteries have a more silvery look, indicating that light is reflected before it reaches the blood itself.…”

Section: Discussionmentioning

confidence: 99%

In Vivo Assessment of Retinal Vascular Wall Dimensions

Fischer

Huber

Feng

et al. 2010

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

Transgenic αSMA-GFP expression in murine vessel wall components allowed quantification of retinal vessel outer diameters in vivo. Although arterioles and venules differ in lumen and vessel wall width, they share a common outer diameter, leading to an AVR(od) close to unity. Because vessel walls are primary targets in common hypertensive and metabolic diseases, αSMA-GFP transgenic mice may prove valuable in the detailed assessment of such disorders in vivo.

show abstract

“…This occurs mostly in smaller vessels in 600 nm (measurement) oximetry images but can occur at either wavelength whenever the measurement encounters a strong central reflex. We note that the central reflex is more recognizable in arteries (Brinchmann-Hansen & Sandvik, 1986;Miri et al, 2017) and more prominent in red light (Narasimha-Iyer et al, 2008). The return of single-pass light in vessels from intense scatter into retinal layers from the optic nerve head can also result in negative ODs near the rim of the disc.…”

Section: Central Vessel Reflex Leads To Inaccurate Saturation Measuresmentioning

confidence: 72%

Potential measurement error from vessel reflex and multiple light paths in dual‐wavelength retinal oximetry

Beach,

Shoemaker,

Eckert

et al. 2023

Acta Ophthalmologica

View full text Add to dashboard Cite

PurposeThis study aims to characterize the dependence of measured retinal arterial and venous saturation on vessel diameter and central reflex in retinal oximetry, with an ultimate goal of identifying potential causes and suggesting approaches to improve measurement accuracy.MethodsIn 10 subjects, oxygen saturation, vessel diameter and optical density are obtained using Oxymap Analyzer software without diameter correction. Diameter dependence of saturation is characterized using linear regression between measured values of saturation and diameter. Occurrences of negative values of vessel optical densities (ODs) associated with central vessel reflex are acquired from Oxymap Analyzer. A conceptual model is used to calculate the ratio of optical densities (ODRs) according to retinal reflectance properties and single and double‐pass light transmission across fixed path lengths. Model‐predicted values are compared with measured oximetry values at different vessel diameters.ResultsVenous saturation shows an inverse relationship with vessel diameter (D) across subjects, with a mean slope of −0.180 (SE = 0.022) %/μm (20 < D < 180 μm) and a more rapid saturation increase at small vessel diameters reaching to over 80%. Arterial saturation yields smaller positive and negative slopes in individual subjects, with an average of −0.007 (SE = 0.021) %/μm (20 < D < 200 μm) across all subjects. Measurements where vessel brightness exceeds that of the retinal background result in negative values of optical density, causing an artifactual increase in saturation. Optimization of model reflectance values produces a good fit of the conceptual model to measured ODRs.ConclusionMeasurement artefacts in retinal oximetry are caused by strong central vessel reflections, and apparent diameter sensitivity may result from single and double‐pass transmission in vessels. Improvement in correction for vessel diameter is indicated for arteries however further study is necessary for venous corrections.

show abstract

The intensity of the light reflex on retinal arteries and veins

Cited by 14 publications

References 17 publications

Retinal Microvascular Signs May Provide Clues to the Underlying Vasculopathy in Patients With Deep Intracerebral Hemorrhage

Retinal Microvascular Signs May Provide Clues to the Underlying Vasculopathy in Patients With Deep Intracerebral Hemorrhage

In Vivo Assessment of Retinal Vascular Wall Dimensions

Potential measurement error from vessel reflex and multiple light paths in dual‐wavelength retinal oximetry

Contact Info

Product

Resources

About