Optic neuritis

What it is

Optic neuritis is inflammation of the optic nerve, the cable that carries visual signals from the eye to the brain. It usually affects one eye and develops over hours to days, causing the vision in that eye to become blurred, dim or partly lost.

Common symptoms

Symptoms often come on fairly quickly over a few days.

• Blurred, dim or lost vision in one eye
• Pain behind or around the eye, worse when moving the eye
• Reduced colour vision, with colours looking washed out
• A central blind spot or patchy vision in some cases

Causes and links

It is often autoimmune, where the body's defences mistakenly attack the optic nerve. It is commonly associated with multiple sclerosis, though it can also follow infection or occur on its own. A first episode needs investigation to understand the cause and risk of recurrence.

Treatment and outlook

Many people recover useful vision over weeks to months, even without treatment, but urgent assessment is still needed. Treatment may include steroid medicines to speed recovery, and follow-up to check for conditions such as multiple sclerosis. Sudden vision loss in one eye should never be ignored.