Visual symptoms are quite common in MS. They can result from damage to the optic nerve or from an incoordination in the eye muscles, neither of which is correctable with eyeglasses. The optic nerve connects the eye to the brain. Inflammation or demyelination in the optic nerve causes optic neuritis, which is experienced as a temporary loss or disturbance in vision and possibly pain behind the affected eye. Typically, vision returns partially or fully within a few weeks. While it is quite rare for a person with MS to become totally blind, it is not at all uncommon for an individual to have recurrent episodes of optic neuritis over the course of the disease, usually in one eye at a time. Damage to the optic nerve can result in a blurring of vision, which may or may not totally resolve over time. This blurring of vision is not correctable with eyeglasses because it is the result of nerve damage rather than changes in the shape of the eye. Colour vision requires a great many nerve fibres from the eye for accurate transmission and is particularly susceptible to changes from demyelination.

Although episodes of optic neuritis typically resolve spontaneously, acute loss of vision used to be treated fairly routinely with low doses of oral cortisone in order to end the episode more quickly. Recent research has demonstrated that high-dose corticosteroids such as methylprednisolone (Solu-Medrol®) or dexamethasone (Decadron®) are more effective in the treatment of optic neuritis. If visual loss is relatively mild and manageable, the best alternative is probably to wait for the episode to remit on its own. However, a course of high-dose corticosteroids may be prescribed if everyday functioning becomes too impaired.

Optic neuritis can cause a large, noticeable "blind spot" in the centre of the visual field, and the person experiences a visual image with a dark, blank area in the middle. This is called a central scotoma and is not correctable with either eyeglasses or medication, although steroids may be helpful in the early, acute phase.

Diplopia (double vision), the experience of seeing two of everything, is caused by weakening or incoordination of eye muscles. This symptom is typically treated with a short course of steroids. Patching one eye while trying to drive or read will stop the double image; however, permanent patching of the eye will slow the brain's remarkable ability to accommodate to the weakness and produce a single image in spite of the weakened muscles. Some physicians are prescribing eyeglasses with special prisms that help to minimise double vision.

Upon examination, the physician may detect a rhythmic jerkiness or bounce in one or both eyes. This relatively common visual finding in MS is nystagmus. Nystagmus does not always cause symptoms of which the person is aware. In the event that it does become troublesome, clonazepan (Klonopin®) is sometimes effective in reducing this annoying but painless problem.

Source: Multiple Sclerosis The Questions You have - The Answers You Need, By: Rosalind C Kalb, PhD, Second Edition, 2000, New York: Demos, pp37-39. ISBN: 1 888 799 43 9

Reproduced with kind permission from Demos Medical Publishing
Available from Demos Medical Publishing, 386 Park Avenue South, Suite 201, New York, NY 10016, USA. Tel +(212) 683 0072. Fax: +(212) 683 0118. Web site: www.demosmedpub.com or by e-mail to orderdept@demospub.com

Source:

Multiple Sclerosis The Questions You have - The Answers You Need, By: Rosalind C Kalb, PhD, Second Edition, 2000, New York: Demos, pp37-39. ISBN: 1 888 799 43 9

Reproduced with kind permission from Demos Medical Publishing
Available from Demos Medical Publishing, 386 Park Avenue South, Suite 201, New York, NY 10016, USA. Tel +(212) 683 0072. Fax: +(212) 683 0118. Web site: www.demosmedpub.com or by e-mail to orderdept@demospub.com