Multiple sclerosis is a disease in which a person’s immune system mistakes its own healthy tissue as foreign and attacks it. MS affects the brain and spinal cord. This is known as the central nervous system (CNS). The CNS is the command center that sends electrical signals, via nerves, to all parts of the body. The eyes are also a part of the central nervous system.
During a flare up, nerve fibers and their surrounding protective fatty layer, called the myelin sheath, are attacked by the body. The immune system’s reaction to foreign tissue is inflammation. This inflammation damages the myelin sheath surrounding the nerves, in a process called demyelination. As a result, signals traveling in the injured part of the brain and spinal cord are interrupted or delayed.
How does multiple sclerosis impact the eyes and vision?The optic nerve connecting the eyes to the brain can become inflamed during an MS flare up. Another way that the eye is impacted is when areas of the CNS that control eye movement and motion are affected.
Most people with multiple sclerosis have episodes of inflammation that may come and go over time, affecting different regions of the CNS. This is known as “relapsing-remitting MS.” In some cases, symptoms may continue to gradually worsen over time, without remission and usually without episodes of inflammation. This is called “progressive MS.”
An episode can be triggered by stress or infection, and different body systems can be affected. As a result, symptoms can range from difficulty with coordination and balance, weakness and fatigue, to eye pain and blurry vision.
What are common symptoms of MS?Symptoms of MS can last for days or weeks. These symptoms may improve on their own, although they often need treatment. Episodes of inflammation are unpredictable, and a person may not experience symptoms again for weeks to years. Treatment to reduce episodes of inflammation is generally required.
Common symptoms of multiple sclerosis include:
Weakness
Fatigue
Numbness and tingling
Difficulty with balance and coordination
Changes in bladder function
Memory or concentration difficulties
The most common vision and eye complications of multiple sclerosis include:
Optic neuritis
Nystagmus (involuntary, uncontrolled rhythmic eye movements)
In people with multiple sclerosis, optic neuritis, diplopia and nystagmus can occur at the same time or during different episodes. These symptoms can make it difficult to accomplish daily activities such as reading, driving, cooking or even walking. It is critical to contact a doctor quickly if any of these symptoms are noticed.
Optic NeuritisThe optic nerve transfers light signals from the retina, the light sensitive tissue in the back of the eye, to the brain — where they are processed as visual images.
During an attack, the optic nerve can become inflamed, a condition that is called optic neuritis. When this occurs, the nerve is not able to relay signals from the eyes to the brain very well.
Optic neuritis in multiple sclerosis usually occurs in only one eye, although it can occur in both. About half of people with MS develop optic neuritis at some point during the disease. Around 20% of people with MS have optic neuritis as the first sign of multiple sclerosis.
Symptoms can last 4-12 weeks, with greatest intensity within the first few days. Symptoms of optic neuritis include:
Pain with eye movement — This is often the first symptom of optic neuritis
Temporary blindness in one eye
Hazy area in center of vision
Dim or graying of color vision
Pulfrich phenomenon — an object swinging back and forth is seen as moving in a circle.
Uhthoff phenomenon — vision becomes worse when body temperature rises
A comprehensive eye and medical evaluation as well as imaging studies may be required to diagnose optic neuritis. Optical coherence tomography (OCT) is a non-invasive tool that can help to identify how the layers of the retina are affected by a flare up.
A team of doctors, such as an eye doctor and neurologist, may work together to manage and treat this condition. Special vision charts that use low contrast letters rather than the usual high contrast letters can be used to measure the degree of vision loss.
The severity and range of optic neuritis symptoms can vary. As a result, treatment differs for individual cases. In some instances, optic neuritis may go away by itself with no lasting vision complications. In other cases, a doctor may need to prescribe medications such as intravenous steroids to decrease the inflammation of the optic nerve and to more quickly improve vision.
Double vision (diplopia)In an individual with multiple sclerosis, the brain stem can be affected in an episode of inflammation. Inflammation in this area can affect the nerves and portions of the CNS that control the muscles responsible for coordinating eye movement. Due to this, the eyes may not be able to work together as a team. When eye movements are not in sync, two different images are sent to the brain — resulting in distorted or double vision.
Double vision can cause dizziness and difficulty with balance in some people with MS. It can make reading much more difficult as well. People with MS may need medications or other treatments during an episode.
In many cases, symptoms of double vision will improve over time. Use of an eye patch or special glasses, called prism glasses, are sometimes recommended to manage double vision.
NystagmusNystagmus is uncontrollable rapid eye movements that can be up and down or side to side. As a result, a person may be disoriented and feel as if the room is moving. Nystagmus can occur due to inflammation of the brain stem or the cerebellum. Like double vision, it can lead to dizziness and difficulty with balance.
As with other episodes of demyelination, treatment with medications or other medical interventions may be required. In many people, the symptoms of nystagmus may improve over time.
Tilting the head at a certain angle can help some people to decrease the feeling of disorientation. However, if nystagmus continues for a longer period of time, medication may be needed to treat it.
Who is at risk?Multiple sclerosis is not hereditary, although someone with a family member with MS is at higher risk. It is also not contagious. It is a chronic (lifelong) condition that can occur at any age.
MS is one of the most common neurological causes of disability in young people — and is most commonly diagnosed when a person is in their 20’s or 30’s. Women are 2-3X more likely to be diagnosed with MS than men.
A personal storyNearly 1 million people in the United States, and more than 2.3 million globally, live with MS. According to the National Multiple Sclerosis Society, about 200 people are diagnosed with MS every week.
One of these people is Martha. She shares her experience of how MS impacted her eyes and vision, and why she never misses a scheduled eye exam:
“I was diagnosed with multiple sclerosis my senior year in college when I lost my ability to speak coherently. After three years of exacerbations causing loss of speech, Bell's palsy and bouts of generalized paralysis, I woke up one morning to find my vision severely disturbed. The world looked like an old malfunctioning television screen rolling. It was terrifying because I had no idea what had happened or how to make it stop.
The only way I could function without feeling incredibly nauseated and off balance was to keep my right eye closed. I finally made my way to a mirror and figured out that I had lost control of my right eye movements. My eye appeared to be constantly rolling around, and I couldn’t make it stop. I was able to get to the ER (with the help of a friend) where I learned I was experiencing something called ‘nystagmus,’ a relatively common symptom experienced by those of us with MS.
For a few weeks, I couldn’t function with both of my eyes open. I had to wear an eye patch both to keep me from the extreme nausea and to allow me to move through life without feeling as though the world was spinning around me. After about three weeks of high doses of steroids, my eye settled back to normal, and I’ve (thankfully!) not experienced the nystagmus since.
I also never miss my annual eye exams because my doctor keeps a close ‘eye’ on my optic nerve to ensure I’m not showing signs of optic neuritis, another common symptom of multiple sclerosis.”
Where can I find resources for vision issues from multiple sclerosis?Martha is not alone in her experience. When vision is affected by multiple sclerosis, it can be disruptive and anxiety inducing. Having a team of trusted healthcare providers such as eye doctors and neurologists is critical to managing the eye and vision complications of MS.
If a person experiences permanent vision impairment due to multiple sclerosis, performing everyday activities can become a challenge. Low vision eye doctors are trained to perform a specialized eye exam. They are also knowledgeable about the latest devices and technology aids for those affected by vision impairment. This includes magnifiers, special electronic devices and other assistive technology.
The National Eye Institute provides a list of vision rehabilitation resources that can assist with finding low vision specialists.
