Retinal vascular imaging: a new tool in microvascular disease research.

The microcirculation is relatively inaccessible to direct visualization and investigation. Recent methods have been developed which use advanced retinal photographic imaging techniques and computer-assisted image analysis to characterize, measure and quantify subtle variations and abnormalities in the retinal vasculature. These quantitative and qualitative assessments demonstrate a close association of retinal vascular signs to both clinical and subclinical cerebrovascular, cardiovascular and metabolic outcomes. Retinal vascular imaging may thus offer potential as a noninvasive research tool to probe the role and pathophysiology of the microvasculature, and as a cardiovascular risk prediction tool. Key areas where retinal vascular imaging has contributed to increased understanding of microvascular pathology and major areas of current and new research are discussed in this review.