Electron microscopic study of human papilledema.

Papilledema associated with neoplastic invasion of the orbit in the optic disks of two patients was found and examined by light and electron microscopy. Pathologic changes in the optic nerve head and nerve included axonal degeneration and mild interstitial edema. Axonal swelling appeared to be the major factor in the overall increase in tissue volume of the optic nerve head. Vascular and perivascular glial alterations were nonspecific.