[Inflammatory optic neuropathies]

Diagnosis of inflammatory optic neuropathy is very likely in a young adult presenting acute, unilateral and painful visual loss. Relative afferent pupillary defect is a very sensitive and specific sign of optic neuropathy. Ophthalmological exam is mandatory to estimate severity of visual loss, appearance of optic disks and check for another eye disease. Magnetic resonance imaging is indicated to rule out a compressive optic neuropathy and to quantify the inflammatory lesion index, which is the best prognostic indicator of multiple sclerosis development (MRI is abnormal at entry in about 50% of patients with isolated optic neuritis). Spontaneous outcome of optic neuropathies is favourable. Corticosteroids have demonstrated efficacy only in shortening length of evolution and by using parenteral high doses. Clinical benefit from introducing beta-interferons treatment after a first episode of isolated optic neuritis remains to be evaluated. Secondary inflammatory optic neuritis (infection, vasculitis, sarcoïdosis) are rare and usually present atypical evolution or other symptoms.