Blood supply to optic nerve head and its understanding and subsequent recent advances has changed the whole concept. Before we only knew that optic nerve head is supplied by post ciliary artery which is a branch of an ophthalmic artery which in turn is a branch of internal carotid. It was SS Hayreh who changed the whole concept according to him post c artery after supplying the disc has got segmental distribution in choroid and the choroidal arteries are end arteries.
That meant if there is some impairment in the flow of blood in pc it is not going to produce changes only at disc but in peripapillary choroid characterized by cavernous degeneration of optic disc. Furthermore filling of blood at optic disc and peripapillary choroid depends upon difference of IOP and perfusion pressure greater the difference better is the perfusion pressure and better filling in LPCA in other simple…
