 |
|
||||||||||||||||||||||||||
Vision and visual symptoms
- Optic neuritis
- Acute blurring or loss of vision, usually in one eye
- Possible to have optic neuritis without affecting vision
- Not everyone who experiences optic neuritis develops MS
- Uncontrolled eye movements
- Double vision
Visual symptoms are not uncommon in people with MS, but rarely result in total blindness.
Optic neuritis
Optic neuritis is an inflammation of the optic nerve, the nerve that transmits light and visual images from the retina to the brain. Because the nerve is located behind ("retro") the globe of the eye, the condition is also known as retrobulbar neuritis.It has been estimated that about 55% of people with MS will have an episode of optic neuritis. Frequently, it is the first symptom of MS.
Acute blurring or loss of Vvsion, usually in one eye
Optic neuritis is generally experienced as an acute blurring, graying,or loss of vision, almost always in one eye. It is rare that both eyes are affected at the same time. There may or may not be pain in the affected eye. Loss of vision usually reaches its maximum extent within a few days and generally improves within 4 to 12 weeks. Recent studies suggest that a short course of methylprednisolone administered intravenously,followed by a tapered course of oral steroids may be useful in helping to reverse the inflammation and restore vision. There is, however, no definitive evidence that treatment with steroids produces a more complete recovery than that which would have happened without treatment.
Possible to have optic neuritis without affecting vision
A person may have a subclinical episode of optic neuritis. That is, there may be demyelination of the optic nerve that occurs without affecting visual function so that the person is not aware of any symptoms. Demyelination, or destruction of myelin, the fatty sheath surrounding and insulating nerve fibers,causes nerve impulses to be slowed or halted and produces the symptoms of MS. In these subclinical cases, visual evoked potentials, electrical diagnostic tests, are very useful in demonstrating evidence of lesions, or damaged areas, along the optic pathways.
Not everyone who experiences optic neuritis develops MS
Not everyone who has an episode of optic neuritis goes on to develop MS. Studies with up to 10 years of follow-up have demonstrated that approximately 50-60% of people with isolated optic neuritis go on to develop MS. More recent studies reported that those persons with optic neuritis who also had abnormalities in their cerebrospinal fluid or on MRI were more likely to develop MS.Other studies have shown that a majority of people with optic neuritis have evidence of demyelination in the brain as seen on MRI scanning. While other disease processes can cause optic neuritis, in a young, otherwise healthy person, MS is most likely to be the cause.
Uncontrolled eye movements
Nystagmus, or uncontrolled horizontal or vertical eye movements, is another common symptom. Nystagmus may be mild and only occur with an extreme lateral gaze, or it may be severe enough to impair vision. Some drugs and special prisms have been reported to be successful in treating the visual deficits caused by nystagmus and a related eye movement disorder, opsoclonus, which causes "jumping vision."
Double vision
Diplopia, or double vision, occurs when the pair of muscles that control a particular eye movement are not perfectly coordinated due to weakness in one or both pairs of muscles. When the images are not properly fused, the patient perceives a false double image. Diplopia usually resolves on its own. In some cases, a brief course of corticosteroids may be helpful. Patching one eye can also be useful. Special lenses are rarely recommended because the symptom tends to be transitory.
Source - NMSS Information Resource Center and Library. Compendium of Multiple Sclerosis Information (CMSI). © 1997, National Multiple Sclerosis Society. Rev. 10/97. Reproduced with permission.
