It is important to note that multiple sclerosis does not affect the eyeball directly. The optic nerves in each eye convert light we see to electrical impulses that travel down the optic nerves to the brain.
Motor control of our eyes is controlled by nerves connecting into musculature that moves our eyes.
Processing of the electrical impulses from our eyes is processed in the brain by neurons which are also nerve cells.
There are numerous diseases and conditions that can impact a person’s vision and thus it is important to engage your health care provider(s) should vision problems occur.
The visual symptoms that occur in MS may be the result of optic neuritis — inflammation of the optic nerve — or lesions (damaged areas) along the nerve pathways that control eye movements and visual coordination. Optic neuritis may result in blurring or graying of vision, or blindness in one eye. A scotoma or dark spot may occur in the center of the visual field.
Optic neuritis is almost always self-limiting, and affected individuals generally make a good recovery. Studies suggest that treatment with intravenous methylprednisolone, sometimes followed by a tapered course of oral steroids, may be useful.
Optic neuritis is often one of the first symptoms people experience in MS.
Nystagmus, or uncontrolled horizontal or vertical eye movements, may be mild — only occurring when the person looks to the side — or it may be severe enough to impair vision. Some medications 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.”
Diplopia & Cranial Palsy
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 person perceives a false double image. Double vision may increase with fatigue or overuse of the eyes (e.g., with extended reading or computer work), and improve with rest. Resting the eyes periodically throughout the day can be beneficial.
Diplopia usually resolves without treatment. In some cases, a brief course of corticosteroids may be helpful. Patching one eye can also be useful for driving or other short tasks, but is not recommended for long periods of time since it will slow the brain’s ability to accommodate to the problem. Special lenses are rarely recommended because the symptom tends to be transitory.
These various visual symptoms are common in people who live with multiple sclerosis but rarely result in total blindness.
Often optic neuritis is one of the first symptoms that presents itself in newly diagnosed individuals thought usually not the only symptom.
There are many diseases or conditions that can result in visual dysfunction. It is important to consult an eye care professional for any visual problem that lasts more than 48 hours especially if there appears to be no particular reason for the dysfunction.
If other forms of symptoms occur in conjunction with a visual dysfunction such as fatigue, weakness, walking problems, pins and needles feelings, itching that does not go away when scratched it is wise to schedule an appointment with a neurologist quickly. If a neurologist is not readily available or cannot see you promptly a visit to your local hospital may be in order.
In many diseases including multiple sclerosis early intervention tends to lead to the best long term outcomes of patients.