Papilledema is swelling (edema) of the optic nerve head due to raised intracranial pressure (cf. other causes of disc swelling, which may cause pseudopapilledema).
A number of stages of papilledema are described: in the acute stage, the only findings may be edema at the superior and inferior poles of the disc, absence of spontaneous venous pulsation, and enlargement of the blind spot. As papilledema progresses the whole disc is involved and splinter hemorrhages may be evident at the disc margin. These early stages may be asymptomatic, or may be associated with transient losses of vision (obscurations), often provoked by activities or movements which further raise intracranial pressure, thus compromising retinal perfusion pressure. Enlargement of the blind spot and constriction of the visual field may be evident, but visual acuity is often unimpaired (cf. disc swelling due to papillitis). Chronic papilledema produces gliosis of the optic nerve head and eventually optic atrophy ("sequential optic atrophy") with nerve fibre damage and permanent visual field defects.