Introduction: Optic neuritis could be the first presentation of a range of relapsing demyelinating syndromes. Here, we evaluated if the extent of optic nerve inflammation at first presentation would be predictive of the disease course and visual outcome.

Methods: 17 patients with clinical diagnosis of optic neuritis were identified from a single centre.  MRI scans were reviewed by two neuroradiologists, unaware of the final diagnosis, and the inflammation along the anterior visual pathways were scored (0-10; +1 for each segment, orbital, canalicular, intracranial,chiasmal, tract, each eye) as previously described (J Neuro-ophthalmology 2013; 33: 123-7). In 10 patients with optimal orbital imaging, clinical and radiological outcomes were evaluated.

Results: 10 patients (8 Female, median age 11 year; range 5.5-15 yrs) had a median orbital imaging score of 4 (range 2-8). Seven had bilateral involvement and 3 unilateral at outset. The diagnosis at final follow-up (median 22months) was Neuromyelitis optica (2), isolated optic neuritis (5), relapsing remitting multiple sclerosis (1), and polyfocal inflammatory demyelination (2). Patients scoring 5 and above (n=4), showed persistence of signal change on repeat optic nerve and /or brain imaging. One patient scoring 8 had relapsing optic neuritis. Visual outcome was good in patients who did not have a relapsing optic nerve demyelination.

Conclusion: The neuroimaging extend of optic nerve involvement at first presentation may be useful in predicting a relapsing form of demyelination, but larger scale studies are now required to evaluate the utility of this as an early predictor of relapsing variants of optic neuritis or polyfocal demyelination.