Papilledema is edema of the optic nerve due to compression or pressure.
What is Papilledema?

ptic disc appearance, case 2. Fundoscopy of the left eye (a) and right eye (b) reveals grade IV papilledema as evidenced by severe elevation and hemorrhages.Minocycline-associated pseudotumor cerebri with severe papilledema. Bababeygy SR, Repka MX, Subramanian PS - Journal of ophthalmology (2010). Not Altered. CC.