Microangioarchitecture of optic papilla.

Two hundred postmortem normal human eyes of 100 cases were studied by four methods to investigate the microangioarchitecture of the optic papilla. The following results have been obtained. The Zinn's circle is important to the blood supply of the optic papilla. It gives off tributaries to the papillar prelaminar and laminar layers and pial vessel network at the retrolaminar portion. The blood supply of the prelaminar layer comes directly from the branches of the short posterior ciliary arteries and Zinn's circle, while the choroidal vessels contribute only a few branches to this area. The above two results are not consistent with Hayreh's idea. Between the central retinal artery system and short posterior ciliary artery system, there are anastomoses at the pial vessel network and in the optic nerve at the retrolaminar portion, but none is found, obviously, in the intraocular portion of the optic nerve. The microangioarchitecture of the optic papilla is accommodated to the nerve in which it resides. The most superficial vessels are radiating, those in the prelaminar and laminar layers are lamellar, and those in the retrolaminar portion are an interwoven network. The caliber of the capillary at the prelaminar and laminar layers is the narrowest, therefore, an ischemic change easily takes place right here.