Vascular supply to the optic nerve of primates

The vascular system of the optic nerve head was studied in eight species of primates. The Bushbaby had an unusual vascular supply, but all the others were quite similar to the human. There is overlapping arterial supply of the disk derived from the pial network on the optic nerve behind the globe, the short posterior ciliary arteries (not anastomatically joined to form a circle of Zinn-Haller), and the central retinal artery. These are connected anastomotically at the capillary level. Venous drainage is accomplished by at least two routes-the central retinal vein and the vortex veins.