Incipient Optic Neuritis

Optic neuritis typically entails discrete attacks of rapidly-evolving, transiently painful vision loss with recovery over weeks to months. Though nadir acuity and prognosis vary according to etiology (e.g., multiple sclerosis, NMO, anti- MOG), the natural history of each attack is generally similar. However, the classic natural history of optic neuritis has exceptions. Atypical resolution of optic neuritis is well described (i.e., chronic relapsing inflammatory optic neuropathy), but atypical onset of optic neuritis is poorly defined. We describe 3 patients with unusually protracted courses between symptom onset and progression to typical optic neuritis. We term this early, forme fruste disease state 'incipient optic neuritis.'