Comprehensive Guide to Special Senses Eyes and Ears Practice Test

The retina has dual blood supply: the inner retina is nourished mainly by the central retinal artery, while the outer retina, including the photoreceptors, is supplied by the choroidal circulation fed by the posterior ciliary arteries. Vessels in the optic nerve sheath primarily perfuse the optic nerve itself (and surrounding meninges) rather than the retinal tissue. So the optic nerve sheath vessels are not a primary source of retinal blood supply, whereas the central retinal artery and the choroidal circulation via the posterior ciliary arteries are.