Vascular Reactivity Response Characteristics to Hypoxia

Oxygen is a necessary part of our everyday lives and is important for normal eye function. Blood flow through the retinal vasculature supplies oxygen to the inner retina. The resistance of the retinal vessels can change, increasing and decreasing blood flow by dilation and constriction of the vessel. The response of retinal hemodynamics to vasoactive stimuli is termed vascular reactivity. To investigate vascular reactivity characteristics, a system that prospectively targets a certain level of oxygen is employed. We characterize how the retinal vessels respond over time to hypoxia as well as define vascular reactivity to different oxygen concentrations in healthy participants. We demonstrate that the vessels increase diameter fully after 6 minutes and flow after 10 minutes. The relationship between retinal hemodynamics and arterial partial pressure of oxygen (PaO2) is demonstrated in healthy humans. Future studies should investigate these changes in diseased models to better understand when the retinal vasculature response may be insufficient.MAS