Hydrodynamic experiments after intravascular injection of human orbital vessels, angiofluorographic observations in vivo, histopathological studies of glaucomatous and vascular optic atrophies and clinical studies showed that the most important contribution to the nutrition of the lamina cribrosa and the anterior optic nerve is derived from the choroidal and ciliary vascular system. The significance of the optic nerve branches from the central retinal artery was not clear.