Feeding the Sense of Sight

When light hits your retina, the neurons there quickly convert this information into electrical signals that the brain can recognize as an image. To support this energy-demanding task, retinal neurons signal to nearby blood vessels to dilate, allowing them easy access to oxygen- and nutrient-rich blood. 

In this image of the vasculature of the rat retina, the large artery on the left delivers blood that feeds into the smaller capillaries (in green). The deoxygenated blood is then carried out of the retina by the vein on the right.