A recent study has revealed a graded association between metabolic risk factors and the width and tortuosity of retinal venules. Researchers found the changes even in patients without clinical diabetes. Findings suggest that type 2 diabetes risk factors and prevalent type 2 diabetes are associated with the morphologic features of retinal venules, both in terms of width and tortuosity, whereas coronary risk factors have a greater influence on arteriolar width.

Researchers analyzed data from the United Kingdom component of the European Prospective Investigation into Cancer study, which examined 25,639 participants 40 to 79 years of age at baseline between 1993 and 1997. From this dataset, the cross-sectional study examined 279,802 arterioles and 285,791 venules from 5,947 participants. The study also showed associations between risk factors and body mass index and levels of triglycerides, both of which were absent when examining arteriolar width. After excluding those without hypertension and cardiovascular disease, atherosclerotic risk factors correlated more closely with arteriolar width. The strongest associations observed were those with age and smoking, where there was arteriolar narrowing and increased tortuosity per decade increase in age and, with current smoking, appreciable arteriolar and venular dilation.

The presence of differential retinal vasculometry associations with cardiometabolic risk factors underlines the importance of making separate arteriolar and venular width and tortuosity measures. These results have the authors calling into question the validity of arteriolar-to-venular ratio measures for cardiovascular risk profiling. They deem it possible that relative changes in vessel indices over time and perhaps variations in measures along the length of a vessel may be stronger predictors of vascular health than absolute size. As it stands, further evaluation of noninvasive microvasculature measures can help establish them as predictors of future cardiometabolic disease.

Owen CG, Rudnicka AR, Welikala RA, et al. Retinal vasculometry association with cardiometabolic risk factors in the European Prospective Investigation of Cancer—Norfolk Study. Ophthalmol. 2019;126(1):96-106.