How can optic neuritis affect my vision if I have multiple sclerosis (MS)?

Optic neuritis, a common first sign of multiple sclerosis (MS), can cause blurry vision, blind spots, dimmed color and eye pain.

A follow-up study of people with optic neuritis found that the majority of those examined 15 years later had 20/20 vision in the affected eye. The study also found that the long-term quality of vision for people treated with high-dose intravenous (IV) corticosteroids was similar to those who were not. In other words, high-dose IV steroid treatment did not negatively impact long-term quality of vision.

Not all of those studied who had optic neuritis went on to develop MS. Of those who did, researchers found that 60 percent had normal vision during the follow-up exams. People with MS were more likely than the overall group, however, to report problems like double vision and trouble focusing on moving objects.
Louis Rosner

The classic case of optic neuritis (ON) attack starts with the initial symptom of simple blurred vision. There is usually a sudden onset - the medical term for the occurrence of the first symptom. ON commonly occurs in one eye and vision can be described as blurry, foggy, misty, cloudy, fuzzy, or distorted. Usually vision loss is in one central spot, called the scotoma, or in the entire eye. When the lesion is in the optic chiasma, the point where the two optic nerves meet, vision will be impaired on the outer side of each eye. ON in both eyes simultaneously is rare, but it is not uncommon to have ON occur in one eye and later in the other. Depth perception can also be impaired, and patients will describe difficulties in judging steps or the position of a moving ball in games like tennis, golf, or football.

Pain and tenderness with eye movement can be present at some stage and can also be accompanied by headache. As vision begins to improve, an effect called movement phosphenes can occur, and the patient will see a bright flash upon eye movement in the dark. The pupils' reaction to light is often affected with ON. While the normal pupil will constrict as a reflex reaction to light, it remains relatively dilated in optic neuritis.

The ON attack will usually reach a peak in a few days. Then there is usually a rather quick recovery within two to six weeks. Sometimes the recovery is slow, and occasionally it is incomplete, leaving decreased visual acuity in the affected eye. When individuals do suffer some loss of vision, it is generally modest, with 20/20 vision becoming 20/30 or 20/40. It is a general rule, however, that good vision returns after the initial attack of ON. Nevertheless, complete recovery does not mean that the optic nerve is completely normal, as seer with what is called Uhthoff's phenomenon.

Uhthoff's phenomenon was first described in 1890, when the German ophthalmologist Wilhelm Uhthoff discovered that some individuals had temporary blurring of vision following strenuous exercise. Uhthoff's phenomenon usually improves slowly, and most people learn to avoid it. It is thought to be a result of a rise in body temperature.

Multiple Sclerosis

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Multiple Sclerosis

Too often, multiple sclerosis is thought of only as "the crippler of young adults." But in fact, 75 percent of all people with MS will never need a wheelchair. In Multiple Sclerosis, Dr. Louis J....

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.