Optic neuritis is a demyelinating inflammatory condition affecting the optic nerve. It usually affects young women and can be the first sign of multiple sclerosis.
It causes a variable degree of visual disturbance (acuity) which usually comes on quite rapidly and is usually central (scotoma). Commonly, it causes a change in colour vision, chiefly red desaturation.
On examination of the fundus, the picture may be normal, or the patient may have a swollen optic disc and/or relative afferent pupil defect.
Optic neuritis is normally self-limiting and no treatment will aid its cure. However steroids may be useful (in potential MS patients) to reduce the recurrence of ON or slow the onset of MS.
Notes on Medicine/Surgery 