Retinal Oxygen Delivery and Extraction in Ophthalmologically Healthy Subjects With Different Blood Pressure Status

Abstract

Purpose To compare retinal oxygen delivery (DO 2 ) and oxygen extraction (VO 2 ) in ophthalmologically healthy subjects with different blood pressure (BP) status. Methods In this case-control study, we prospectively included 93 eyes of 93 subjects (aged 50–65 years) from a Dutch cohort ( n = 167,000) and allocated them to four groups (low BP, normal BP [controls], treated arterial hypertension [AHT], untreated AHT). We estimated vascular calibers from fundus images and fractal dimension from optical coherence tomography angiography scans. We combined calibers, fractal dimension, BP, and intraocular pressure measurements in a proxy of retinal blood flow (RBF), using a Poiseuille-based model. We measured arterial and venous oxygen saturations (S a O 2 , S v O 2 ) with a scanning laser ophthalmoscope. We calculated the DO 2 and VO 2 from the RBF, S a O 2 , and S v O 2 . We compared the DO 2 and VO 2 between groups and investigated the DO 2 –VO 2 association. Results DO 2 and VO 2 were different between groups ( P = 0.009, P = 0.036, respectively). In a post hoc analysis, the low BP group had lower DO 2 than the untreated AHT group ( P = 4.9 × 10 −4 ). The low BP group and the treated AHT group had a lower VO 2 than the untreated AHT group ( P = 0.021 and P = 0.034, respectively). There was a significant DO 2 –VO 2 correlation (R obs = 0.65, b obs = 0.51, P = 2.4 × 10 −12 ). After correcting for shared measurement error, the slope was not significant. Conclusions The DO 2 and VO 2 were altered in ophthalmologically healthy subjects with different BP status. Future studies could elucidate whether these changes can explain the increased risk of ophthalmic pathologies in those subjects. Translational Relevance Understanding the baseline interplay between BP, retinal perfusion, and oxygenation allows for improved evaluation of retinal disease manifestation.

Association between localized retinal nerve fiber layer defects in nonglaucomatous eyes and metabolic syndrome: a propensity score-matched analysis

“…We found that localized RNFL defects were associated with central obesity. Previous studies also reported that obesity (high BMI) was associated with a thinner RNFL ( 4 - 6 ). In a recent study, a higher BMI was associated with reduced retinal oxygen delivery and extraction in healthy subjects.…”

“…Localized RNFL defects have been associated with certain components of metabolic syndrome in previous studies, including obesity ( 4 - 6 ), cardiovascular risk factors ( 7 ), hypertension ( 7 - 10 ), and albuminuria in patients with type 2 diabetes ( 11 ). Metabolic syndrome is a growing epidemic estimated at 1.4 billion worldwide and rising every year ( 12 ).…”

A case of choroidal melanocytosis observed by multimodal imaging with laser speckle flowgraphy

“…Oxygen supply to the inner retina is provided solely by the retinal circulation, whereas oxygen supply to the outer retina is provided primarily by diffusion from the choroidal circulation, with negligible supply from the retinal circulation [ 21 ]. Through autoregulatory mechanisms and vessel wall remodeling, the oxygen volume delivered to the outer retinal tissues can be controlled to some extent by the extraction of oxygen from the retinal circulation.…”

Retinal Vessel Caliber Measurement Bias in Fundus Images in the Presence of the Central Light Reflex

“…The exact criteria, rationale, and power specifications of the recruitment process have been described extensively in our recent studies on the same population. 26 , 27 In short, the subjects included were required to fall into one of four predefined groups: low BP, normal BP, treated high BP, and untreated high BP. Subjects in the low BP group were invited based on documented recordings of systolic BP (SBP) and diastolic BP (DBP) that were below the respective 10th percentile of the population on two or more separate occasions.…”