An inflammatory disorder of the nervous system characterized by multiple neurologic symptoms over time. Multiple sclerosis (MS) occurs because of inflammation of the nerves in the body and brain. A myelin sheath normally surrounds the nerves in the body, acting just like the “insulation” on electrical wires. With MS, inflammation causes this insulation to break down, effectively “short circuiting” the normal nerve transmission. The eye is one of the areas most often affected as the optic nerve contains over a million individual nerve fibers. Inflammation in this nerve causes vision problems – this is called optic neuritis and is often one of the first symptoms of MS.