0ptic nerve head of rhesus monkey with optic disc edema secondary to raised intracranial pressure.
(A) Note elevation of floor of optic disc. In peripapillary region (arrows), retina is displaced laterally, and axons have vacuolated appearance and abut retinal pigment epithelium (toluidine blue stain, original magnification x 110). (Reproduced from Tso and Hayreh. 1977a)
(B) Optic disc edema (toluidine blue stain, original magnification x 100).