Retinal hemodynamic oxygen reactivity assessed by perfusion velocity, blood oximetry and vessel diameter measurements

TY - JOUR

T1 - Retinal hemodynamic oxygen reactivity assessed by perfusion velocity, blood oximetry and vessel diameter measurements

AU - Klefter, Oliver Niels

AU - Lauritsen, Anne Øberg

AU - Larsen, Michael

N1 - © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

PY - 2015/5/1

Y1 - 2015/5/1

N2 - Purpose To test the oxygen reactivity of a fundus photographic method of measuring macular perfusion velocity and to integrate macular perfusion velocities with measurements of retinal vessel diameters and blood oxygen saturation. Methods Sixteen eyes in 16 healthy volunteers were studied at two examination sessions using motion-contrast velocimetry and retinal oximetry with vessel diameter corrections. To test oxygen reactivity, participants were examined during normoxia, after 15 min of hyperoxia and finally after 45 min of normoxia. Repeatability was assessed by intraclass correlation coefficients (ICC) and limits of agreement. Results Fifteen minutes of hyperoxia was accompanied by mean reductions in arterial and venous perfusion velocities of 14% and 16%, respectively (p = 0.0080; p = 0.0019), constriction of major arteries and veins by 5.5% and 8.2%, respectively (p < 0.0001), increased retinal arterial oxygen saturation from 95.1 ± 5.0% to 96.6 ± 6.4% (p = 0.038) and increased retinal venous oxygen saturation from 62.9 ± 6.7% to 70.3 ± 7.8% (p = 0.0010). Parameters returned to baseline levels after subsequent normoxia. Saturation and vessel diameter ICCs were 0.88-0.98 (range). For perfusion velocities, short-term ICCs were 0.79-0.82 and long-term ICCs were 0.06-0.11. Intersession increases in blood glucose were associated with reductions in perfusion velocities (arterial p = 0.0067; venous p = 0.018). Conclusion Oxygen reactivity testing supported that motion-contrast velocimetry is a valid method for assessing macular perfusion. Results were consistent with previous observations of hyperoxic blood flow reduction using blue field entoptic and laser Doppler velocimetry. Retinal perfusion seemed to be regulated around individual set points according to blood glucose levels. Multimodal measurements may provide comprehensive information about retinal metabolism.

AB - Purpose To test the oxygen reactivity of a fundus photographic method of measuring macular perfusion velocity and to integrate macular perfusion velocities with measurements of retinal vessel diameters and blood oxygen saturation. Methods Sixteen eyes in 16 healthy volunteers were studied at two examination sessions using motion-contrast velocimetry and retinal oximetry with vessel diameter corrections. To test oxygen reactivity, participants were examined during normoxia, after 15 min of hyperoxia and finally after 45 min of normoxia. Repeatability was assessed by intraclass correlation coefficients (ICC) and limits of agreement. Results Fifteen minutes of hyperoxia was accompanied by mean reductions in arterial and venous perfusion velocities of 14% and 16%, respectively (p = 0.0080; p = 0.0019), constriction of major arteries and veins by 5.5% and 8.2%, respectively (p < 0.0001), increased retinal arterial oxygen saturation from 95.1 ± 5.0% to 96.6 ± 6.4% (p = 0.038) and increased retinal venous oxygen saturation from 62.9 ± 6.7% to 70.3 ± 7.8% (p = 0.0010). Parameters returned to baseline levels after subsequent normoxia. Saturation and vessel diameter ICCs were 0.88-0.98 (range). For perfusion velocities, short-term ICCs were 0.79-0.82 and long-term ICCs were 0.06-0.11. Intersession increases in blood glucose were associated with reductions in perfusion velocities (arterial p = 0.0067; venous p = 0.018). Conclusion Oxygen reactivity testing supported that motion-contrast velocimetry is a valid method for assessing macular perfusion. Results were consistent with previous observations of hyperoxic blood flow reduction using blue field entoptic and laser Doppler velocimetry. Retinal perfusion seemed to be regulated around individual set points according to blood glucose levels. Multimodal measurements may provide comprehensive information about retinal metabolism.

KW - Adult

KW - Blood Flow Velocity

KW - Blood Glucose

KW - Blood Pressure

KW - Diagnostic Techniques, Ophthalmological

KW - Female

KW - Hemodynamics

KW - Humans

KW - Hyperoxia

KW - Laser-Doppler Flowmetry

KW - Male

KW - Middle Aged

KW - Oximetry

KW - Oxygen

KW - Regional Blood Flow

KW - Retinal Vessels

KW - Young Adult

U2 - 10.1111/aos.12553

DO - 10.1111/aos.12553

M3 - Journal article

C2 - 25270587

SN - 1755-375X

VL - 93

SP - 232

EP - 241

JO - Acta Ophthalmologica

JF - Acta Ophthalmologica

IS - 3

ER -