Vision problems related to myasthenia gravis (MG) can make reading, driving, and navigating basic daily activities difficult. Eye and vision symptoms are often the first symptoms of myasthenia gravis.

Ocular myasthenia gravis is a type of MG in which the muscles that control your eyes and eyelids become easily tired and weak. While eye symptoms are common for all people living with myasthenia gravis, about 15 percent of people with the condition have only eye-related symptoms.

Like other symptoms of myasthenia gravis, ocular symptoms can differ from person to person. A person’s individual symptoms also can change from day to day — or even throughout the day.

Continue reading to learn more about five eye and vision symptoms that may develop in people with myasthenia gravis.

How Is Ocular Myasthenia Gravis Different From Generalized Myasthenia Gravis?

People with ocular MG don’t experience symptoms in other parts of the body, such as muscle weakness in the arms and legs and difficulty with:

• Swallowing
• Eating
• Breathing
• Talking
• Walking

Someone who has MG symptoms beyond those affecting their eyes and vision is said to have generalized MG.

What Causes Ocular Myasthenia Gravis?

Myasthenia gravis can cause muscle weakness in the muscles you can control, called voluntary muscles. Muscle weakness in MG is caused by communication problems between the nerves and muscles. In a healthy body, the brain sends a signal to the muscles — such as a request to contract — through the nerves. Nerves and muscles don’t quite touch, so nerves use a chemical called acetylcholine to send the signal across a space called the neuromuscular junction to the muscles.

Myasthenia gravis is an autoimmune disease, a condition in which a person’s immune system mistakenly attacks their own healthy tissue. In MG, the immune system makes antibodies (special immune proteins) that attack and destroy the acetylcholine receptor on a person’s muscles. Without enough acetylcholine receptors, a person’s muscles can’t easily receive signals from the brain.

Which MG symptoms a person experiences depends on which muscles their immune system is attacking. The muscles that control the movements of the eye — called extraocular muscles — may be more susceptible to MG-related weakness than other muscles in the body, due to structural differences. Additionally, eye muscles may be more likely to fatigue because they contract more rapidly than muscles in other parts of the body.

When a person’s eye muscles become weaker, they may experience symptoms that affect their eyes and vision.

Does Ocular Myasthenia Gravis Progress?

According to the Myasthenia Gravis Foundation of America, about half of people who have only eye problems in the first year after an MG diagnosis go on to develop generalized MG. People who have only eye-related symptoms of MG for five years or more usually don’t develop generalized MG.

Ocular Symptoms of Myasthenia Gravis

Ocular MG can cause a variety of symptoms. People with ocular MG may experience one or more of the following at different times.

1. Drooping Eyelids

Drooping eyelids — also called ptosis — is one of the most common symptoms of ocular myasthenia gravis. If you have ptosis, your eyelids fall, making it look like your eyes aren’t fully open. If your eyelid covers your pupil, your vision could be blocked. Ptosis can occur when the muscles that hold your eyelids up become fatigued.

Ptosis can affect one or both eyes. You may also experience the curtain effect, where eyelid drooping starts or worsens in one eye when the other eyelid is lifted. You may also notice that your upper eyelid twitches upward if you look down for a prolonged period of time.

If your eyelids block your vision, it may become unsafe for you to drive or do certain other activities. It may also be more difficult to read or watch television.

2. Double Vision

Double vision — also called diplopia — is a common symptom of ocular MG. If you have double vision, you see two images instead of one.

Your eye movements must be aligned for you to have clear vision. Double vision occurs when the muscles that move your eyes in unison become weak or fatigued, causing your eyes to become misaligned. Like other types of muscle weakness in MG, double vision may improve after resting.

In addition to difficulty seeing and reading, double vision can cause symptoms such as:

• Headache
• Nausea
• Dizziness

3. Blurred Vision

Some people experience blurred vision instead of double vision due to weak or fatigued eye muscles. Blurred vision happens when you have trouble focusing your eyes, making things appear less clear or sharp than usual. This is caused by weakness of the muscles that focus the eyes, a process called accommodation.

If you have blurry vision, your symptoms may change throughout the day. You may notice blurry vision in one eye or both eyes.

4. Dry Eyes

Dry eyes are a common symptom in people with myasthenia gravis. About 21 percent of people with ocular MG experience dry eyes. It can be caused by difficulty blinking or difficulty closing your eyes all the way (called lagophthalmos).

Dry eyes may feel different from person to person. Dry eye symptoms may include:

• Burning sensations
• Light sensitivity
• Trouble wearing contact lenses
• Blurred vision
• Gritty eyes
• Stringy mucus in your eye
• Blepharitis (eyelid irritation)

5. Bulging Eyes

If you have a thyroid issue called Graves’ disease, you may have bulging eyes — also called exophthalmos or proptosis. People living with myasthenia gravis are more likely to develop thyroid issues than the general population. Graves’ disease is the most common type of thyroid disease that occurs with myasthenia gravis.

Eye symptoms caused by Graves’ disease are similar to ocular MG symptoms, such as:

• Double vision
• Blurred vision
• Dry eyes
• Swollen, puffy eyes
• Light sensitivity
• Pressure or pain in your eyes

Graves’ disease is another type of autoimmune disease that causes your thyroid gland to become overactive. Graves’ disease can also cause your immune system to attack the tissues and muscles around your eyes, making them inflamed and swollen. This is known as thyroid eye disease. Swollen tissue and inflamed muscles around your eyes can make them appear as if they’re protruding from your face more than usual.

Treatment for Graves’ disease involves antithyroid medications, radioiodine therapy, or surgery to remove the thyroid gland. There are also medications that target the thyroid eye disease directly. After appropriate treatment, 2 out of 3 people with both Graves’ disease and myasthenia gravis will see an improvement in their ocular symptoms.

How Is Ocular Myasthenia Gravis Treated?

Eye and vision problems can have a significantly negative impact on your quality of life, but treatments are available. The treatment you receive will depend on your symptoms. Your neurologist may coordinate your care with a doctor who specializes in treating eyes, called an ophthalmologist.

Some symptoms of ocular MG can be managed or treated with medical devices, including:

• Dark sunglasses — These can help with light sensitivity and fatigue.
• Eyelid tape — This special tape can hold droopy eyelids open without hurting your skin.
• Eyelid crutches — This device attaches to your eyeglasses and can hold droopy eyelids open.
• Eyelid surgery — This procedure lifts the eyelids permanently to prevent drooping.
• Eye patch — Wearing an eye patch over one eye can improve double vision and help with eye fatigue.
• Eyeglass prisms — This special type of eyeglasses helps correct double vision.

If you have severe symptoms, or if they interfere with your quality of life, your doctor may prescribe immune system-modulating therapy, such as:

• Azathioprine
• Corticosteroids, such as prednisone
• Cyclosporine
• Mycophenolate mofetil

It’s important to have regular eye exams if you’re living with MG. Long-term side effects of some medications, such as prednisone, can lead to eye problems like cataracts (cloudy areas on the lens of your eye) or glaucoma (pressure buildup inside your eye).

If you have generalized MG as well as ocular symptoms, your neurologist may recommend other treatment options such as pyridostigmine (Mestinon), thymectomy (surgical removal of the thymus gland), or newer targeted medications.

Talk With Others Who Understand

MGteam is the social network where people with myasthenia gravis and their loved ones come together to ask questions, give advice, and share their stories with others who understand life with myasthenia gravis.

Do you have ocular myasthenia gravis? Have any MG treatments helped your symptoms? Share your experience in the comments below, or start a conversation by posting on your Activities page.