Normative Values and Predictors of Retinal Oxygen Saturation

Jani, Pooja D.; Mwanza, Jean-Claude; Billow, Kyle B.; Waters, Alexa; Moyer, Sarah; Garg, Seema

doi:10.1097/iae.0b013e3182979e7b

Cited by 53 publications

(101 citation statements)

References 38 publications

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“…The average values for saturation and diameter in the four quadrants from normal persons and patients with vision threatening diabetic retinopathy showed the same pattern in the three groups as published previously,17 and also confirms the presence of a significantly higher saturation in the upper than the lower vascular arcades and a higher saturation in the nasal than in the temporal arcades 13 15 21. The observed arterial oxygen saturations below 100% can potentially be explained as a result of counter current exchange in the optic nerve,3 but this phenomenon cannot explain the different oxygen saturation in the four main arterioles shortly after their branching from the central retinal artery.…”

Section: Discussionsupporting

confidence: 85%

Lack of differences in the regional variation of oxygen saturation in larger retinal vessels in diabetic maculopathy and proliferative diabetic retinopathy

Jørgensen

Bek

2016

Br J Ophthalmol

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Section: Discussionsupporting

confidence: 85%

Lack of differences in the regional variation of oxygen saturation in larger retinal vessels in diabetic maculopathy and proliferative diabetic retinopathy

Jørgensen

Bek

2016

Br J Ophthalmol

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“…1). 8 The analysis area was selected by centering quadrant lines on the optic disc. An initial central circle was used to delineate the optic disc.…”

Section: Retinal Oximetrymentioning

confidence: 99%

“…These values were not truncated to 100%, per established oximetry protocol. 5,8,14 Statistical analyses were implemented with Statistical Package for the Social Sciences (SPSS) software (version 20.0; SPSS, Inc., Chicago, IL, USA). One-way analysis of variance (ANOVA) with Tukey's post hoc test was used to compare means, with DR stage as the independent variable and SO 2 as the dependent variable.…”

Section: Retinal Oximetrymentioning

confidence: 99%

“…Studies have shown that the retinal oximeter produces repeatable and reliable measurements when detecting differences in SO 2 levels in controls, as well as in patients with retinal pathology. [3][4][5][6][7] Although normative values for RO have been developed, [8][9][10][11][12] less is known about the measurement of RO in all stages of DR. Furthermore, prior to our work, the correlation of oxygen saturation measured by RO (metabolic state) with the percentage of ischemia assessed by IVFA (anatomic state) was unknown.…”

mentioning

confidence: 99%

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Oxygen Saturation of Retinal Vessels in All Stages of Diabetic Retinopathy and Correlation to Ultra-Wide Field Fluorescein Angiography

Guduru

Martz

Waters

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. The purpose of this study was to determine retinal hemoglobin oxygen saturation (SO 2 ) in patients with diabetic retinopathy (DR) using retinal oximetry (RO) and to correlate the degree of retinal ischemia using intravenous fluorescein angiography (IVFA).METHODS. This is a single-center cross-sectional cohort study. Twenty-seven controls and 60 adult patients with diabetes mellitus (16 without DR and 44 with DR) were enrolled. Patients were stratified according to DR severity. Using RO, SO 2 was measured in major retinal arterioles (SaO 2 ) and venules (SvO 2 ). Using IVFA, the percentage of retinal ischemia in 31 patients with DR was calculated and correlated with RO. RESULTS.Pairwise one-way analysis of variance (ANOVA) showed a significant increase in SaO 2 and SvO 2 in patients with proliferative DR (PDR) compared with controls (SaO 2 : PDR, 100 6 7% vs. controls, 91 6 4% [P ¼ 0.003]; SvO 2 : PDR, 66 6 11% vs. controls, 53 6 6% [P < 0.00001]). The percentage of retinal ischemia also increased with DR severity: ANOVA showed a significant difference in retinal ischemia between all categories of nonproliferative DR vs. PDR: 2.31 6 2% vs. 7.92 6 9% (P ¼ 0.017), respectively. Pearson two-tailed correlation showed significant correlation between SaO 2 and ischemia (R ¼ 0.467, P ¼ 0.011).CONCLUSIONS. Hemoglobin oxygen saturation of retinal arterioles and venules increases with DR severity; SaO 2 correlates with increasing ischemia measured by IVFA. Retinal oximetry may complement current imaging strategies to noninvasively augment the diagnosis and risk stratification of patients with diabetes.Keywords: retinal oximetry, diabetic retinopathy, fluorescein angiography I schemia plays a central role in the pathophysiology of diabetic retinopathy (DR). As ischemia increases, untreated DR generally progresses through four stages in an orderly fashion: mild nonproliferative DR (NPDR), moderate NPDR, severe NPDR, and proliferative DR (PDR). Intravenous fluorescein angiography (IVFA) is the gold standard to assess retinal ischemia and perfusion and is also helpful when determining treatment for DR. However, IVFA is relatively invasive as it requires the intravenous injection of contrast dye. Furthermore, IVFA provides only the anatomic state of retinal vessels and does not give any metabolic information, such as oxygenation.Recently, quantitative measurement of oxygen saturation (SO 2 ) has been possible using retinal oximetry (RO), a noninvasive imaging modality used to estimate hemoglobin oxygen saturation in retinal arterioles and venules. The technical aspects of RO have been previously described in the literature.1-3 Briefly, RO is based on similar principles as standard pulse oximetry, utilizing the light absorbance of oxyhemoglobin and deoxyhemoglobin at the carefully selected wavelengths of 570 and 600 nm. Studies have shown that the retinal oximeter produces repeatable and reliable measurements when detecting differences in SO 2 levels in controls, as well as in patients with retinal pathology. [3][4][5]...

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“…Metabolic dysfunction regarding to impaired vascular supply is directly reflected by retinal oxygen saturation which can be detected noninvasively by dual wavelength fundus photography [3]. Normally, the oxygen saturation in retinal vessels differs along vascular segments and is higher in the macular region than retinal periphery [4]. Many retinal diseases are caused by a dysfunction of the vascular network.…”

mentioning

confidence: 99%

Selected aspects of retinal signaling and energy metabolism and its perspective as a cerebral surrogate model

Albanna¹,

Lüke²,

Alpdogan³

et al. 2018

New Front Ophthalmol

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Purpose: The isolated and superfused retina from vertebrates is routinely used for neurophysiological measurements of basic retinal signal generation and transduction. Such an ex vivo isolated neural network moreover represents a useful model system for the investigation of drugs and toxins and may also be helpful to elucidate molecular mechanisms of CNS diseases. The present overview aims to bring observations to the reader's attention, which, in part, have been made more than 50 years ago and were sparsely followed up upon in subsequent research, but may support the idea that the isolated bovine retina represents a useful system to investigate the physiology and pathophysiology of energy supply to neuronal tissue. Material and methods:Parallel recording of ERGs and pyridine nucleotide oxidation in the isolated and superfused vertebrate retina. The review will focus on topics, which discuss the connection between retinal electrophysiology and underlying energy metabolism.Results: Previous and present reports about (i) transretinal signaling cascades, (ii) the involvement of the pharmacoresistant Cav2.3 / R-type calcium channel in transretinal signaling and (iii) data about the retinal oxygen demands and concentration in different layers are collected, which elucidate that the retina may be used as a cerebral surrogate model in different research areas. Retinal tolerance to ischemia is several times larger than the tolerance in the remaining brain. Conclusions:The retinal energy supply through retinal vessels is regulated and controlled by neurovascular coupling. Classical retinal recording techniques and special retinal abilities in electrical-vascular coupling will be set in perspective with novel recording techniques, currently brought into clinical application for the detection of impaired neurovascular coupling after aneurysmal subarachnoid hemorrhage in the brain. The present review elucidates that important pathophysiological aspects related to the upregulation of pharmacoresistant Cav2.3 / R-type calcium channels during SAH may be investigated in the isolated vertebrate retina. Ischemic tolerance in the vertebrate retinaThe oxygen consumption of the vertebrate retina on a per gram basis has been described as higher than that of the brain [1,2]. Oxygen cannot be "stored" in tissue so that a constant and adequate supply must be guaranteed to preserve function. Metabolic dysfunction regarding to impaired vascular supply is directly reflected by retinal oxygen saturation which can be detected noninvasively by dual wavelength fundus photography [3]. Normally, the oxygen saturation in retinal vessels differs along vascular segments and is higher in the macular region than retinal periphery [4]. Many retinal diseases are caused by a dysfunction of the vascular network. Interestingly, the venous oxygen saturation in diabetic retinopathy was higher in venules draining the macular surroundings than retinal periphery that reflect specific metabolic conditions [5,6].Since a relatively unobstructed light path...

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Normative Values and Predictors of Retinal Oxygen Saturation

Cited by 53 publications

References 38 publications

Lack of differences in the regional variation of oxygen saturation in larger retinal vessels in diabetic maculopathy and proliferative diabetic retinopathy

Lack of differences in the regional variation of oxygen saturation in larger retinal vessels in diabetic maculopathy and proliferative diabetic retinopathy

Oxygen Saturation of Retinal Vessels in All Stages of Diabetic Retinopathy and Correlation to Ultra-Wide Field Fluorescein Angiography

Selected aspects of retinal signaling and energy metabolism and its perspective as a cerebral surrogate model

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