Acute inflammatory demyelinating optic neuritis - Evidence-based visual and neurological considerations

Background: Optic neuritis (ON) is an acute inflammatory demyelinating disorder of the optic nerve that occurs most often in young adults. It can be a monophasic or polyphasic disease isolated to the optic nerve(s) or can be associated with a more widespread demyelinating disorder of the central nervous system such as multiple sclerosis (MS) or neuromyelitis optica. Advances in therapeutics that modify the risk of progression to MS have emphasized accurate diagnosis and risk assessment of patients with ON. Review Summary: ON usually presents with acute unilateral visual loss associated with ocular pain exacerbated by eye movements. Similar to results found in studies assessing corticosteroid used in MS relapses, intravenous methylprednisolone accelerates visual recovery from ON but has no impact on long-term visual outcome. A clinically isolated syndrome (CIS), such as ON, is a clinical demyelinating event that is often the initial attack of relapsing-remitting MS. Disease modifying drugs, in particular interferons-beta, have been shown to reduce the risk of MS conversion in high-risk patients presenting with a CIS. The exact timing and patient selection for the initiation of treatment remain controversial. Conclusion: ON is the best studied CIS. The visual prognosis is excellent in most cases regardless of whether the patient is treated with corticosteroids or not. Three recently completed prospective, randomized, double-blinded, placebo-controlled studies have shown that starting a disease-modifying drug at the time of a CIS can reduce the rate of development of MS, However, better diagnostic tools are needed to precisely predict the conversion to MS and the factors influencing disease severity to determine the most appropriate therapeutic paradigm and avoid unnecessary treatment.