Choroidal blood vessels are a network of blood vessels located in the choroid, a layer of tissue between the retina and the sclera in the eye. These vessels supply oxygen and nutrients to the outer layers of the retina, which are essential for maintaining healthy vision. The choroidal blood supply is crucial for the function of photoreceptors, the cells responsible for converting light into visual signals. Any disruption in the blood flow can lead to various eye conditions, affecting overall visual health and clarity.