Optic nerve multiple sclerosis symptom. Coloured axial magnetic resonance imaging (MRI) scan of the eyes (top) and part of the brain of a 38-year-old woman with vision problems. The scan has revealed a problem with the left optic nerve (upper right), with clinical signs of retrobulbar neuritis, a form of optic neuritis that is often an early sign of multiple sclerosis. Both conditions are caused by demyelination of the nerves. This MRI scan is an example of a T2-weighted scan, with grey inversion and the use of gadolinium as a contrast medium.