Multiple Sclerosis and Vision
According to the Multiple Sclerosis Foundation, virtually everyone who gets multiple sclerosis will experience visual problems at some point over the course of the disease. This hub looks at the visual problems most commonly associated with MS, and offers a few tips for coping when these problems arise.
MS, a neurological disorder, doesn't actually affect the eyes. Visual changes with MS most often stem from damage or inflammation to either the optic nerve or the part of the brain that controls the eye muscles.
The most common visual problem, and one of the most common of all MS symptoms, is optic neuritis. Optic neuritis is often the first sign of MS, and may cause any of the following visual changes:
- blurred vision
- decreased sensitivity to color (colors may appear washed out, and differences in hue may become hard to discern)
- pain when moving the eye
- phosphenes (the appearance of flashing lights in response to eye movements or sudden noises)
- Afferent Pupillary Defect (failure of the pupil to dilate properly in response to changes in light)
- in very rare cases, total loss of vision
Because there are two independent optic nerves, optic neuritis usually affects only one eye at a time. A doctor can sometimes detect optic neuritis by using an ophthalmoscope to examine the back of the eye, where the head of the optic nerve can be seen. If the problem is further back along the nerve, tests known as visual evoked potentials, which measure the speed of signals moving down the optic nerve, can help verify a diagnosis of optic neuritis.
Treating Optic Neuritis
The prognosis for optic neuritis is usually very good. In most cases, the problem gets better on its own over a period of weeks or months (usually less than a year), although recovery is not always 100%. In severe cases, oral and intravenous steroids may be used. These can help speed up recovery time, although the degree of recovery will not be any more complete than if steroids had not been administered. Unfortunately, because the eye itself is undamaged, corrective lenses cannot help with the symptoms of optic neuritis.
Double Vision and Nystagmus
After optic neuritis, the two most common vision problems that occur with MS are diplopia (double vision) and nystagmus (uncontrolled eye movement). Both of these problems can affect balance and orientation. Combined with the leg weakness and gait problems that often accompany MS, these visual problems can be extremely hazardous.
Double Vision (Diplopia)
Diplopia can have many causes, but when it occurs in patients with MS, the cause is usually misalignment of the eyes, meaning that the muscles controlling the eyes are unable to make both eyes converge on exactly the same spot. The problem often resolves on its own, but if not, treatments may include:
- exercises to strengthen the muscles controlling eye movement
- eyeglasses with special prism lenses that bend light enough to compensate for the misalignment
- surgery on the muscles controlling eye movement
- wearing a patch over one eye, so that the brain receives only one image
Nystagmus is uncontrolled movement of the eyes, a condition that makes the world appear to wiggle or jump. This motion is sometimes so subtle that even eye specialists cannot detect it without special equipment. This unpleasant condition may get better on its own. If it doesn't, it can be very hard to treat. Medications including anticonvulsants and muscle relaxants are often tried, but these are not always successfull. Unlike diplopia, surgery is usually not recommended for treatment of nystagmus.
Other Vision Problems With MS
Visual problems occurring less frequently in patients with multiple sclerosis include:
- Ocular Dysmetria: over or under-shooting when moving the eyes to look at something
- Vestibulo-Ocular System Dysfunction: inability of the visual system to adjust to motion or tilting of the head or body, resulting in blurred or distorted vision and disorientation
- Gaze Palsy: inability to move an eye in a specific direction
In the 1890s, neuro-ophthalmologist Wilhelm Uhthoff discovered that exercise increased the severity of optic neuritis symptoms. It was later discovered to be the increase in body temperature caused by exercising, not the exercise itself, that intensified the symptoms. In fact, heat can cause a temporary worsening of many symptoms in patients with MS or other neurological disorders, with vision simply being the first area affected in most cases.
A patient with MS needs to be aware of the potential effects of anything that raises body temperature, including exercise, hot weather, a hot shower or bath, fever or consuming hot food or beverages, especially where their vision is concerned.
This increase in symptoms is not a true flare-up or worsening of the disease, only a temporary situation. No actual neurological damage has occurred, and when the patient's body temperature returns to normal, the worsening of symptoms will subside.
Coping With Visual Problems
There are a number of things a person with low vision can do to make life easier:
- Regularly rest your eyes.
- Alternate visually-intensive activities with things requiring little or no visual effort, such as making phone calls or listening to an audiobook.
- Keep your environment visually simple and uncluttered. Avoid complicated patterns, and arrange objects so that they are easily distinguished from each other.
- Experiment with different types of lighting to see what works best for you.
- Rather than rely on typical lighting placement such as overhead lighting or lamps on end tables, put lights where they shine on the specific areas that will help you the most.
- Remove objects that cause glare, such as shiny objects, reflective surfaces and badly positioned lighting.
- Use color (paint, colored tape, etc) to increase visual contrast and make things stand out.
- Arrange your environment to minimize things that you could bump into, trip over or knock down.
- Avoid overheating.
- Use vision aids such as magnifiers.
- Look for large print versions of items. Most printed materials are available in large print format.
- Use the available options on your computer, such as larger fonts, text to voice software, etc.
While MS is often the cause of the problems described here, It's important to remember that they can have other causes, including potentially serious problems such as glaucoma or detatched retina. A person with multiple sclerosis should not dismiss these symptoms as just their MS "acting up". It could be something else altogether, possibly even something completely treatable if caught early enough. A person experiencing any of these visual problems should visit a doctor as soon as possible.
-  National Multiple Sclerosis Society. Optic Neuritis. http://www.nationalmssociety.org/about-multiple-sclerosis/what-we-know-about-ms/symptoms/visualsymptoms/optic-neuritis/index.aspx
-  National Multiple Sclerosis Society. Vision Problems. 2009
-  All About Multiple Sclerosis. Multiple Sclerosis Symptoms. http://www.mult-sclerosis.org/mssymptoms.html
-  Multiple Sclerosis Resource Centre. Visual Disturbances. http://www.msrc.co.uk/index.cfm/fuseaction/show/pageid/1713
-  US Department of Veteran's Affairs - Multiple Sclerosis Center of Excellence. Visual Dysfunction in Multiple Sclerosis. http://www.va.gov/MS/articles/Visual_Dysfunction_in_Multiple_Sclerosis.asp
-  Multiple Sclerosis Foundation. Optic Neuritis and MS. http://www.msfocus.org/article-details.aspx?articleID=380
-  Multiple Sclerosis Foundation. Eye Movement Abnormalities in MS. http://www.msfocus.org/article-details.aspx?articleID=382