Choroidal blood flow refers to the circulation of blood through the choroid, a layer of blood vessels located between the retina and the sclera in the eye. This blood supply is crucial for providing nutrients and oxygen to the outer layers of the retina, which are essential for maintaining healthy vision. The choroid contains a rich network of blood vessels that help regulate temperature and remove waste products. Proper choroidal blood flow is vital for preventing conditions such as choroidal neovascularization and other retinal diseases that can lead to vision loss.