Autoregulation of the blood supply to the anterior optic nerve and lamina cribrosa.

In the optic nerve an axial arterial system of peripheral origin is present; several intraneural collaterals of the central retinal artery are absent in the majority of cases while a rich pial network always exists. The question whether the central retinal artery should be considered as an important axial nutritional artery for the anterior optic nerve has to be answered in the negative. One or two large centrifugal collaterals running to the pial sheath-network probably play an autoregulatory role, protecting the laminar region from a temporary lack of blood supply during moderate rises in intraocular pressure.