You may know myasthenia gravis (MG) as a condition that affects how nerves and muscles work together. Ocular MG is a type of MG that specifically involves the muscles that control your eyes and eyelids. Around 50 percent of people with MG first notice vision changes and about 85 percent go on to develop muscle weakness in other parts of the body. However, some people experience only eye-related symptoms.

If your vision changes due to ocular MG, you might worry about eventually losing your eyesight. Although some conditions and injuries can cause blindness, ocular MG doesn’t lead to permanent vision loss.

What Is Ocular Myasthenia Gravis?

Ocular MG weakens the extraocular muscles, which control eye movement and help lift the eyelids. You use these muscles when you:

• Blink
• Look side to side or up and down
• Keep your eyes open
• Make certain facial expressions, like raising your eyebrows

Why are the eye muscles especially affected by MG? It’s because extraocular muscles respond differently to an autoimmune attack than other muscles do.

MG is an autoimmune disorder in which the immune system targets specific chemical receptors in muscles, leading to weakness. Eye muscles are more vulnerable because they have fewer of these receptors compared to other muscles. Additionally, extraocular muscles work harder than most muscles, contracting rapidly and frequently throughout the day. This makes them more prone to fatigue, even in people without MG.

Can Myasthenia Gravis Lead to Blindness?

Ocular MG can affect vision, but it doesn’t typically cause blindness. The condition weakens the muscles that control eye movement and eyelid position but doesn’t damage the optic nerve or retina, which are essential for your vision.

Common Vision Changes From Myasthenia Gravis

Eye weakness from MG can fluctuate throughout the day. You might have fewer eye problems after sleeping or closing your eyes for a while. Eye or vision symptoms are typically most noticeable late in the day or after prolonged use, such as driving long distances.

Diplopia (double vision) commonly occurs because weakness of the eye muscles often causes misalignment. When your eyes are misaligned, you see two of the same image. You might have trouble focusing due to ocular MG.

Ptosis (droopy eyelids) is another common ocular MG symptom. When one or both eyelids droop, it can partially block your vision. A droopy upper eyelid may limit your peripheral vision, making it harder to see out of the corner of your eye on the affected side.

Functional Blindness From MG

Although ocular MG doesn’t damage eyesight, its symptoms can lead to functional blindness. Severe ptosis in MG may cause your eyelids to droop so much that they cover most or all of your pupils (the black centers of your eyes), making it hard to open your eyes. When this happens, functional blindness occurs.

Resting your eyes might reduce ptosis temporarily, but even occasional functional blindness can affect your quality of life. Talk to your doctor if the symptoms of ocular MG stop you from working, performing daily tasks, or enjoying activities like reading.

What MGteam Members Say

Members of MGteam have described low vision from ocular MG and its impact on their lives:

• “I enjoy reading, but my vision has been affected by MG — blurry vision as well as double vision.”
• “My eyes are having some focus problems. I’m not seeing double, but in order to read small print, I have to alternately close one eye.”
• “My vision fluctuates from day to day. Some days I see fine with my glasses, some days not so great, and others I don’t need my glasses at all.”
• “I overdid my reading, so now I have double vision. Very frustrating. I love to read!”
• “It’s rough when you wake up with blurred vision because, for me, rest is the answer. My ‘rest’ was always reading, scrolling on Facebook, sewing, TV … anything with my eyes! So for me to ‘rest’ eyes shut, doing nothing, is difficult.”

Can You Have Both Blindness and Myasthenia Gravis?

If you’ve lost your vision and ptosis isn’t the cause, your blindness is likely due to something other than MG. An eye care provider, such as an optometrist or ophthalmologist, can help determine if your vision loss is caused by an issue such as:

• Macular degeneration (damage to the central part of the retina, the light-sensitive layer at the back of the eye)
• Retinopathy (a disease affecting the blood vessels in the retina)
• An injury (usually affects just one eye)

Be sure to keep up with your regularly scheduled eye exams to monitor your vision and eye health.

How Is Vision Loss From Myasthenia Gravis Managed?

Without treatment, changes from ocular MG can impair your vision and reduce your quality of life. Luckily, treatment for ocular MG can help with low vision.

Medications for Myasthenia Gravis

Prescription medications can help treat MG by improving muscle function or reducing immune system attacks. For example:

• Pyridostigmine (Mestinon) improves communication between nerves and muscles, helping reduce muscle weakness, including around the eyes.
• Corticosteroids such as prednisone or prednisolone (Omnipred, Orapred, Pred Mild, and others) help control the immune response to improve symptoms.
• Intravenous immunoglobulin (Asceniv, Bivigam, Gamunex-C, and others) helps regulate the immune system and can reduce symptoms of ocular MG.

Talk to your neurologist about medications to manage your ocular MG.

Prism Lenses

Fresnel prisms are thin, transparent sheets that can be attached to eyeglasses to adjust how light enters the eyes. For many people with ocular MG, prism lenses can help correct double vision. If a temporary prism attachment improves your vision, you may be able to get glasses with built-in prism lenses.

Ptosis Props

Traditional bar ptosis props can be attached to most eyeglasses. These small bars hold up your eyelid so it doesn’t droop and obstruct your vision.

Covering One Eye

Some simple strategies can also improve low vision from ocular MG. For example, if you have double vision, blocking one eye might help. You can do this by wearing an eye patch or placing tape over one lens of your glasses. If you have ptosis and one eyelid already covers an eye, it may naturally reduce your double vision.

What Members Say

Members of MGteam have described their positive experiences with treatment for low vision or vision changes from ocular MG:

• “I received rituximab (Rituxan) and Gamunex-C this month. It’s finally working. Today is the first time in six months that my vision is clear to drive.”
• “I went to my ophthalmologist and got fitted with prism lenses for my glasses. They take away the double vision.”
• “I ended up wearing an eye patch over my right eye so I could read or watch TV. I no longer have double vision, praise the Lord!”
• “Mestinon keeps my eyelid open. Things are looking up.”

Talk With Others Who Understand

MGteam is the social network for people with myasthenia gravis and their loved ones. On MGteam, more than 2,000 members come together to ask questions, give advice, and share their stories with others who understand life with myasthenia gravis.

Have you experienced vision loss from myasthenia gravis? How have you managed this symptom? Share your experience in the comments below, or start a conversation by posting on your Activities page.