The choroid is the vessel plexus of the eyeball and lies between the sclera
and retina. The choroid is the main supplier of nutrients to the eyeball.
Fine vessels run in the choroid and supply the optic cells of the retina.
The choroid is supplied with blood from the ciliary circulation which recieves
blood from the opthalmic artery. There are three layers to the choroid: the
large vessel layer the small vessel layer of Bruch's membrane which is associated
with the retina.