The optic nerve is an extension of the brain that connects the retina of the eye to the brain. The retina contains photoreceptors, cells that are activated by light and that connect to other retinal cells called ganglion cells. These, in turn, send long projections called axons into the brain. By this route, the optic nerve sends visual impulses to the brain.
Optic neuritis is the most common optic nerve disease to affect young people.
The average age at the first attack is 31 years, but teenagers and persons over 40 may develop this disease for the first time. It is an inflammatory disease of uncertain cause, which affects more women than men. Commonly there is aching pain in the eye made worse by eye movement. The pain often goes away within a week or so but the blurred vision lasts for weeks to several months. Three fourths of the patients have nearly complete return of central vision, as measured by reading the eye chart.