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G. Michelson, M. Scibor; Intravascular Oxygen Saturation in Retinal Vessels in Normals During Flicker . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3914.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To measure oxygen saturation in retinal arteries and veins during flicker provocation. Methods: In 11 eyes of 11 healthy subjects (mean age 30+–12 years) we examined the oxygen saturation in retinal vessels by the Imaging Spectrometer (Jena). The estimation of the oxygen saturation OS2arterial and OS2venous of retinal vessels was based on the evaluation of different extinction spectra of hemoglobin and oxy–hemoglobin. The arterio–venous difference avD was calculated by the equation avD = OS2arterial – OS2venous. The measurement of OS2arterial and OS2venous was performed before flicker, 30sec, 60 sec and 180 sec during provocation with flicker, and 360 sec after finishing flicker. The light provocation of the retina was performed 180 sec with a full–field luminance flicker with 10 Hz. For statistical analyses, the non–parametric Mann–Whitney–Wilcoxon test were performed. Results: The oxygen saturation in retinal arteries and veins, and the arterio–venous–difference (+– standard deviation) was before flicker 92.8+– 3.3% (OS2arterial), 59.8+–1.9% (SO2venous), and 34.0+–1.4% (avD). During flicker the venous oxygen saturation SO2venous decreased significantly by –7.6 % +– 2.6%. SO2venous stepped down from 59.8% (before), to 57.4+–2.3 (after 30 sec flicker), to 54.7+–2.8% (after 60 sec flicker), and to 52.2% (after 180 sec flicker). 3 minutes after finishing flicker the venous oxygen saturation became normal (57.8+–2%). The arterial oxygen saturation remained stable under flicker (93.5+–1.2% after 180 sec flicker). The arterio–venous difference increased significantly under flicker to 44.3% after 180 sec flicker provocation. Conclusions: During flicker normal eyes showed a significant decrease of the venous oxygen saturation and an increase of the arterio–venous difference in retinal vessels. Measuring retinal oxygen saturation in retinal arteries and veins during flicker might be a new test to detect impaired regulation of the blood supply of the retinal ganglion cells during phases of increased neuronal activity.
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