Progression of optic neuritis to multiple sclerosis: an 8-year follow-up study

Objective: The relationship between acute monosymptomatic optic neuritis (A ON) and subsequent multiple sclerosis (MS) is still doubtful. We investigat ed the risk of developing MS in patients from North Bavaria, who were suffe ring from AON. Patients/methods: Twenty-nine patients with clinical evidenc e of AON were included in the study. Initial evaluation included brain reso nance imaging (MRI) and a clinical neurological examination. Follow-up exam inations were performed after 72-108 months (mean: 96 months) in 26 patient s (three patients were lost to follow-up) and consisted of a second complet e neurological examination. Diagnosis of MS was established according to th e criteria of Poser CM, Paty DW, Scheinberg L. New diagnostic criteria for multiple sclerosis: guidelines for research protocols. Ann Neurol 1983;13:2 27-231. Results: At follow-up, 14 of 26 patients (54%) had converted to cli nically definite MS. Nine patients (64%) had developed MS within 2 years af ter the onset of AON. Conclusion: We observed the development of MS in 54% of the 26 investigated AON patients. The exceptional feature of the present study was the relatively long follow-up period of 8 years. (C) 1999 Elsevi er Science B.V. All rights reserved.