Update on retinal vascular caliber.

Retinal vessels are the only blood vessels that can be viewed directly, in vivo, repetitively and non-invasively. Retinal vessel caliber is influenced by physiological (age, sex, race, blood pressure, blood glucose, body mass index) and pathological (atherosclerosis, dyslipidemia, smoking) determinants. There are studies on large population groups that demonstrate the associations between retinal vasculature and subclinical or clinical changes in systemic diseases (hypertension, diabetes, stroke, renal or cardiac diseases). The assessment of retinal vessels can provide information about the pathophysiology of many diseases, but it also has a direct applicability in clinic, being used as a screening method that predicts the risk of their occurrence.