Swelling or edema of the optic nerve head may be visualized by ophthalmoscopy. It produces haziness of the nerve fibre layer obscuring the underlying vessels; there may also be hemorrhages and loss of spontaneous retinal venous pulsation. Disc swelling due to edema must be distinguished from pseudopapilledema, elevation of the optic disc not due to edema, in which the nerve fibre layer is clearly seen.
Disc swelling may be due to raised intracranial pressure (papilledema, q.v.), or local inflammation of the optic nerve (papillitis), and may be associated with marked impairment of vision, for example in optic neuritis, or be without specific visual complaint (as may be the case in papilledema). The clinical history, visual acuity and visual fields may help determine the cause of disc swelling.
Recognized causes of disc swelling include:
- Optic neuritis
- Acute ischemic optic neuropathy (arteritic, nonarteritic) Orbital compressive lesions, for example, optic nerve sheath meningioma (Foster Kennedy syndrome)
- Graves ophthalmopathy (through compression of retinal veins by myositis)
- Central retinal vein occlusion
- Infiltration: carcinoma, lymphoma, granuloma
- Raised intracranial pressure (papilledema; more usually bilateral)
- Raised intracranial pressure (papilledema)
- Malignant hypertension
High CSF protein, as in Guillain-Barré syndrome
- Any of the unilateral causes