Optic neuritis

May involve the retrobulbar (retrobulbar neuritis) or the intrabulbar (papillitis) portion of the optic nerve, or both.

Idiopathic ON, the most common form of ON, is an inflammatory optic neuropathy in the absence of evidence of a systemic inflammatory disease.

May occur in isolation or be a manifestation, often the first, of multiple sclerosis (MS).

Investigations including MRI of the brain can help predict the risk of conversion to MS and can dictate early intervention with disease-modifying treatments (interferon-beta, glatiramer acetate) that reduces the risk of conversion to MS.

Acute treatment for idiopathic ON includes intravenous corticosteroid treatment followed by oral prednisone or observation alone.

Oral prednisone alone should not be used in the treatment of idiopathic acute ON.

Optic neuritis (ON) represents inflammation of the optic nerve. By far the most common form is idiopathic ON, which is a primary demyelinating disease occurring in isolation or as part of multiple sclerosis (MS).[1]Ebers GC. Optic neuritis and multiple sclerosis. Arch Neurol. 1985 Jul;42(7):702-4. http://www.ncbi.nlm.nih.gov/pubmed/4015469?tool=bestpractice.com [2]Optic Neuritis Study Group. The clinical profile of optic neuritis: experience of the Optic Neuritis Treatment Trial. Arch Ophthalmol. 1991 Dec;109(12):1673-8. http://www.ncbi.nlm.nih.gov/pubmed/1841573?tool=bestpractice.com When in isolation, primary demyelinating ON is considered a forme fruste of MS. ON manifests as the subacute or acute onset of pain in the eye and pain with eye movements and loss of vision, typically with central or centrocecal scotoma that usually reaches a nadir at approximately 1 to 2 weeks. ON recovers over several months, with ultimate visual acuity that is possibly reduced but seldom severely so.