The retina lies in the back of the eye and is a multi-layered tissue which detects visual images. These images are transmitted to the brain through approximately 1 million tiny nerve fibers. These nerve fibers converge in the back of the eye, before going to the brain, into a bundle called the optic nerve. If some or all of the nerve fibers are damaged, visual capability deteriorates.

When the optic nerve becomes inflamed, this condition is called optic neuritis. The nerve tissue becomes swollen and red, and the nerve fibers do not work properly. If many of the nerve fibers are involved, the vision may be dramatically affected, but if the optic neuritis is mild, vision is nearly normal. Optic neuritis can be caused by other diseases and conditions and may affect the optic nerve of one or both eyes.

Some people, especially children, develop optic neuritis following a viral illness such as mumps, measles, or a cold. In others, optic neuritis may occur as a sign of a more serious neurological disease affecting nerves in various parts of the body, such as multiple sclerosis. In a rare condition called Leber's optic neuropathy, which often runs in families, a special kind of optic neuritis may appear in both eyes within a short span of time. Often, the cause for optic neuritis is unknown.

Optic neuritis usually comes on suddenly, and the patient notices blurred vision in one or both eyes. The vision is dim, like somebody turned down the lights, and colors may appear to be washed out. There may be pain in the area of the eye socket, especially when moving the eyes. The vision may continue to get worse over a week or two, and may seem worse after exercising or a hot bath.

A careful description of these symptoms is important to your doctor for the diagnosis of optic neuritis. The optic nerve enters the back of the eye where it appears as a small disc. Your eye doctor can examine the optic nerve inside the eye by using a special diagnostic instruments or lens. Swelling of the optic nerve may or may not be visible. If the optic nerve inflammation occurs inside the eye, it can be readily detected. If swelling of the nerve occurs behind the eye, the doctor may not be able to see the swollen nerve tissue.

Since optic neuritis can be confused with many other causes of poor vision, an accurate medical diagnosis is important. MRI, CT scans, visual brain wave recordings or laboratory blood tests may be ordered to rule out other systemic diseases. Other vision tests which may be performed include color vision, side vision, and pupil reactions to light.

The treatment for optic neuritis can sometimes vary. Steroid is the treatment of choice and is usually given as an initial high dose intravenous form followed by an oral form. This may accelerate the healing process and lessen the chance of developing other associated neurological disease later. In many cases, patients with optic neuritis improve without treatment. The vision and the peripheral field of vision may return to normal or suffer some residual and permanent damages.