Optic neuritis usually affects one eye. Symptoms might include: 
Pain. Most people who develop optic neuritis have eye pain that's worsened by eye movement. Sometimes the pain feels like a dull ache behind the eye.
Vision loss in one eye. Most people have at least some temporary reduction in vision, but the extent of loss varies. Noticeable vision loss usually develops over hours or days and improves over several weeks to months. Vision loss is permanent in some people.
Visual field loss. Side vision loss can occur in any pattern, such as central vision loss or peripheral vision loss.
Loss of color vision. Optic neuritis often affects color perception. You might notice that colors appear less vivid than normal.
Flashing lights. Some people with optic neuritis report seeing flashing or flickering lights with eye movements.
