Papilledema

Papilledema is optic disc swelling caused specifically by raised intracranial pressure (ICP). It is a clinical finding, not a diagnosis by itself, so the immediate task is to identify why pressure is elevated and whether vision is being damaged. The optic nerve is surrounded by a subarachnoid space containing cerebrospinal fluid. When ICP rises, that pressure is transmitted along the optic nerve sheath to the optic nerve head. The resulting compression disrupts axoplasmic transport at the lamina cribrosa; axons swell, the disc becomes elevated, and retinal nerve-fibre function begins to deteriorate. Persistent pressure can progress to optic atrophy and irreversible visual loss. Papilledema is usually bilateral, although asymmetry is common. Early visual acuity may remain relatively good, while the patient notices brief episodes of greying or “blackout” of vision, often when bending, coughing, or changing position. An enlarged blind spot, arcuate field loss, impaired colour vision, or an afferent pupillary defect indicates more significant optic-nerve dysfunction. Headache, pulsatile tinnitus, nausea, transient visual obscurations, and horizontal diplopia from sixth-nerve dysfunction strengthen the raised-ICP pattern. The duration and severity of swelling matter...