The Relationship between Retinal Vascular Reactivity and Arteriolar Diameter in Respo

[ODwire.org NewsBot]

The Relationship between Retinal Vascular Reactivity and Arteriolar Diameter in Response to Metabolic Provocation. Invest Ophthalmol Vis Sci. 2009 Apr 1; Authors: Tayyari F, Venkataraman ST, Gilmore ED, Wong T, Fisher J, Hudson C Purpose: To compare the magnitude of vascular reactivity in response to metabolic provocation in retinal arterioles of varying diameter in healthy, young subjects. Method: Ten healthy, young subjects (mean age 26.2yrs, SD 3.5) attended for three sessions. Session 1 was used to select 2 discrete hemodynamic measurement sites along the superior temporal arteriole. Retinal arteriolar blood flow was assessed at relatively narrow and wide sites using the Canon Laser Blood Flowmeter. At sessions 2 and 3, CO2 and O2 were sequentially administered (and alternated across sessions) using manual gas flow control via a modified sequential re-breathing circuit to achieve target hypercapnia and hyperoxia. Blood flow was assessed for each gas phase. Total vascular reactivity capacity (TVRC) was taken as the difference in flow between hypercapnia and hyperoxia. Results: The baseline diameter for the narrow and wide measurement sites was 92.4microm (+/-13.6) and 116.7 microm (+/-12.7), respectively (ReANOVA p