Non‐invasive vascular impedance measures demonstrate ocular vasoconstriction during isometric exercise

摘要

AimsThe calculation of impedance for a vascular network is a common method used in circulation studies. Impedance indices (the ratios of the harmonics of pressure to the harmonics of flow) provide the investigator with a measure of the opposition to blood flow in a pulsatile system and are a proven indicator for vasculopathy. Previous studies investigating the eye's opposition to blood flow have concentrated on simple measures of resistance (the ratio of mean pressure difference to mean flow) which are more appropriate to a steady state or non‐pulsatile system. The purpose of this study is to demonstrate a new, non‐invasive, method to determine the vascular impedance of the eye during the known physiologic stress of sustained isometric exercise.