Optic neuritis is a common eye problem where inflammation or demyelination affects the optic nerve. It is a condition in its own right, but is also strongly associated with multiple sclerosis. Not everyone who experiences optic neuritis goes on to develop further symptoms of MS, but a significant proportion do.
For 1 in 4 people with MS, optic neuritis was the first MS symptom that they noticed.
Optic neuritis usually comes on suddenly and causes blind spots or areas of poor vision in one eye. Colour vision or visual field can be severely affected. You might also have pain, particularly when you move your eyes.
Optic neuritis generally gets worse over a few days and reaches a peak about two weeks from onset. After that, symptoms generally improve and you will usually have recovered within 4-6 weeks. However, you may find that problems with your vision persist longer than this.
Optic neuritis is common in the general population, affecting between one and five people in 1000. Like multiple sclerosis itself, optic neuritis normally affects people aged between 20 and 40 and women more than men. Seven out of ten of people with MS will experience optic neuritis at some point.
Optic neuritis is usually temporary and associated with good recovery. You may be offered steroids as a treatment, which is intended to reduce the inflammation quickly and prevent permanent damage to the nerve. There is no long-term difference in progression and recovery between those that do take steroids and who choose not to.
Given the connection with MS, if you have optic neuritis you are likely to be asked to undergo a range of tests. These could include blood tests, an MRI scan and visual evoked potential tests, to see whether your doctor can diagnose MS. Getting treatment early can reduce the severity and progression of MS.
Bear in mind that the symptoms experienced with optic neuritis could be due to other eye conditions or headaches. Optic neuritis is also associated with a rare condition called neuromyelitis optica. The treatments for this and MS are different, and so a doctor needs to confirm exactly what is going on for you.