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H. Kergoat, S. Jean–Louis, J.V. Lovasik; Oxygen Inhalation Induces Uniform Vasoconstriction in All Retinal Quadrants . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3909.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Purpose: Many studies have evaluated the changes in retinal vessel diameter during altered physiology or pathology. These studies were mainly based on analyses of individual fundus photographs and as such did not allow the evaluation of vessel dynamics over time. Our research objective was to detail the time–course and amplitude changes in the diameter of arteries and veins across the retinal quadrants, before, during and after hyperoxic vascular stress. Methods: Methods: Vasomotor dynamics of retinal vessels were quantified with a Retinal Vessel Analyzer that digitized the fundus image in real time, and simultaneously quantified dynamic changes in vessel diameter. The arterial and venous diameters within one disc diameter of the optic nerve head in each quadrant were studied. Twenty young adults participated in this study where the vessel diameters were measured during successive phases of breathing either room air or pure oxygen. The oxygen saturation level (SaO2), end–tidal carbon dioxide (EtCO2), pulse rate (PR), respiratory rate (RR) and blood pressure (BP) were also monitored throughout testing. Results: Results: Breathing 100% O2 caused an increase in SaO2 and a decrease in the EtCO2. All other systemic parameters measured (PR, RR, BP, OPP) remained unchanged. However, the retinal veins and arteries constricted by ∼14% and ∼9% respectively, in all retinal quadrants. After the experimental hyperoxia, inhalation of room air was associated with a progressive increase in the caliber of vessels back towards their pre–test size. The amplitude and overall profile of vessel reactivity to and recovery from hyperoxia was the same across retinal quadrants. Conclusions: Conclusions: Retinal vessels change caliber uniformly across retinal quadrants during a transient systemic hyperoxic stress. This type of physiological vascular provocation may have diagnostic use for vascular pathologies of the eye, and assessing the quality of vascular regulation during normal senescence.
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