Acute retinal necrosis associated optic neuropathy.

Acute retinal necrosis (ARN) syndrome is characterized by severe intraocular inflammation, occlusive vasculopathy and peripheral retinal necrosis. Vision threatening complications of this syndrome include retinal detachment, macular oedema and ischaemia and optic neuropathy. Optic nerve involvement may be the presenting sign of ARN and this condition should be included in the differential diagnosis of acute papillitis. Several mechanisms may lead to ARN associated optic neuropathy including vasculitis, optic nerve ischaemia and direct optic nerve invasion by the herpes virus. We review optic nerve involvement during ARN and present its incidence, pathogenesis, differential diagnosis and treatment.