Occlusion of the posterior ciliary arteries, resulting in infarction of the optic nerve head

Aetiology

• Can be caused by temporal (giant cell) arteritis - arteritic ION
  • Posterior ciliary arteries become affected - wall becomes so inflamed/thickened that lumen becomes occluded
• Non-arteric ION is due to non-inflammatory disease of small blood vessels - vascular risk factors

Clinical features

• Sudden visual loss
• Usually painless

Signs of ION associated with GCA

• Headache
• Scalp tenderness
• Enlarged temporal arteries

Investigations

Fundoscopy

• Pale, swollen disc

Management

• Management of GCA involves steroids