caliber: a standalone construct

In vascular medicine, caliber is the lumen diameter of a blood vessel, and retinal vessel caliber in particular is the width of the arterioles and venules photographed at the back of the eye, treated as a non-invasive marker of microvascular health. Narrower retinal arterioles and wider venules track with hypertension and with the risk of cardiovascular disease. Hubbard and colleagues' 1999 Methods for evaluation of retinal microvascular abnormalities associated with hypertension/sclerosis in the Atherosclerosis Risk in Communities Study set out the standard way to grade these vessel calibers from retinal photographs. The referent is a measured vessel width summarised as an arteriole-to-venule ratio, an entirely different construct from the bore of a gun, which it shares only the word with.[1]

Unit

The vessel lumen diameter, in micrometres, often summarised as the arteriole-to-venule ratio

Recovery means

Not applicable

Measured by

Graded from digitised retinal photographs by summarising arteriolar and venular diameters into central-equivalent calibers