Remote ischemia affects the diameter of larger retinal vessels in normal persons

Abstract

PurposeRemote ischemic conditioning (RIC) implies that repeated episodes of ischemia in one organ can protect another remote organ from the adverse consequences of ischemia. It remains to be elucidated whether the diameter response in retinal vessels can be used as a marker of RIC in general and whether the response can be used to predict the effect of RIC on the visual prognosis in diseases characterized by retinal ischemia.MethodsIn twenty normal persons aged 20–31 years the Dynamic Vessel Analyzer (DVA) was used to measure the resting diameter and diameter changes during isometric exercise and flicker stimulation before, immediately after, and one hour after RIC induced by transient ischemia in the left arm.ResultsThe baseline diameter of retinal venules was reduced non‐significantly immediately after (p = 0.07) and significantly one hour after RIC (p < 0.009), whereas the baseline diameter of arterioles was unaffected by the intervention (p > 0.61). Arterial constriction induced by isometric exercise was significantly reduced immediately after RIC (p < 0.04), but not one hour after RIC (p > 0.99). None of the other diameter responsese were affected by RIC (p > 0.22 for all comparisons).ConclusionsThe diameter of large retinal vessels is affected one hour after controlled transient ischemia in the left arm. This indicates that the diameter response of retinal vessels could be a potential marker of ischemic conditioning in the body in general. The potential of remote ischemic conditioning as an intervention on vision threatening retinal diseases where ischemia is a part of the pathogenesis should be investigated.