Acute Optic Neuritis (AON) causes an acute inflammation of the optic nerve. It is a rare disease (prevalence 5/100 000, with 130,000 patients/year in Europe and US) occurring in adults between the age 20 and 40 years.
It produces sub-acute loss of vision and eye pain occurring over several days. There is a slow improvement within 1- to 3-month but the vision deficits persists in 65 to 75% of patients with QoL impairment.
AON is mainly related to multiple sclerosis (1st sign in 30% of MS patients, >50% MS patients will have AON) but idiopathic origin is also seen.
AON offers a measurable imaging endpoint (thinning of retinal layers by Optical Coherence Tomography, OCT) correlated with clinical outcome. There is no approved treatment for repair and the standard of care is the administration of IV corticosteroids that have no effect on long-term protection.