Sixth nerve palsy is a nerve issue that affects eye muscle control. Having it makes it hard or impossible to turn an affected eye outward. It has many possible causes but is rare overall. Most of the causes are treatable, and often, treatment isn’t even necessary. Early diagnosis and treatment are key in preventing permanent effects.
Sixth nerve palsy is a condition where damage to a specific nerve disrupts eye movement and alignment. It’s usually one-sided (unilateral) and affects one eye only, but it can sometimes affect both eyes (bilateral). It’s also known as abducens (pronounced “ab-DEW-sens”) nerve palsy.
Your 12 cranial nerves connect to your brain directly and come in pairs, each having a left and right side. Your sixth cranial nerve pair, also known as the abducens nerve, connects to the lateral rectus muscle on each of your eyes.
Your lateral rectus muscles pull outward. They help your left eye look left and your right eye look right. Sixth nerve palsy disrupts signals traveling through the nerve, causing weakness or paralysis in the lateral rectus muscle.
Sixth nerve palsy is rare. Worldwide, there are between 370,000 and 900,000 new cases annually. In the U.S., there are between 15,000 and 37,000 new cases annually.
Anyone can develop sixth nerve palsy, but the odds increase significantly at age 50 and keep rising as you age. Available research indicates the risk of developing it is highest between ages 60 and 75.
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The symptoms of sixth nerve palsy happen because you can’t move or align your eyes properly. Some symptoms are possible with just sixth nerve palsy, while others may occur with conditions that can cause or contribute to sixth nerve palsy.
The main symptoms of sixth nerve palsy include:
Sixth nerve palsy can happen with any condition or event that can damage your abducens nerve. And sections of it travel through your brain, so conditions that affect the brain itself can also affect the abducens nerve.
Many cases of sixth nerve palsy are idiopathic, meaning they happen for unknown reasons. But the majority of cases do have causes experts can find and diagnose. Those causes include:
Like the brain tissue surrounding it, the abducens nerve is vulnerable to damage from a head injury. Examples include:
Viruses, bacteria and other microbial invaders can attack your nervous system, including the abducens nerve. Examples include:
Disruptions in blood flow and circulation inside your brain can affect the abducens nerve. Without blood flow, a problem called ischemia (pronounced “iss-KEY-me-uh”) develops. That’s when cells malfunction when they aren’t getting enough blood flow. The affected cells die if ischemia is severe and/or lasts too long.
Circulatory conditions and events that can cause sixth nerve palsy include:
Conditions that affect multiple body systems can also cause or contribute to sixth nerve palsy. Examples include:
Conditions that affect your blood can cause increased pressure inside your skull, which can cause surrounding brain tissue to press on and damage the abducens nerve. And other growths inside your brain can press on the abducens nerve. Examples include:
Many other neurological (nervous system-related) conditions can cause or contribute to sixth nerve palsy. Examples include:
Certain medical procedures or treatments can affect or damage the abducens nerve. Some examples include:
Some people may have a higher risk of developing sixth nerve palsy. In many cases, a cause like those listed above may not be the main cause, but it might make it easier for something else to cause sixth nerve palsy. Examples include:
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The complications of sixth nerve palsy depend strongly on the underlying cause and treatments used for this condition. Because these can vary widely, your healthcare provider is the best source of information about the possible or likely complications in your case and what you can do to avoid or minimize them.
One key complication providers will try to avoid in children is amblyopia (lazy eye). It happens when a child’s brain starts relying more and more on one eye and ignoring input from the other. The unused eye’s alignment will “drift” out of position and worsen.
A health care provider, such as an ophthalmologist, neurologist or neuro-ophthalmologist, can diagnose sixth nerve palsy using a combination of methods. Those include:
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The treatments for sixth nerve palsy vary widely, and they usually fall into one of two categories:
The main factor is what’s causing it, but other factors play a role, too. Treating the underlying condition is usually enough for sixth nerve palsy to go away on its own. Because so many factors can determine the best treatment for sixth nerve palsy, your healthcare provider is the best source of information about the best treatment options. They can tailor the information to fit your specific situation and needs.
For many people, little or no treatment is necessary. If your case doesn’t appear to need treatment early on, your healthcare provider or eye specialist will schedule follow-up visits to monitor your condition. Treating the palsy will only happen if it becomes necessary. However, treating the effects of the palsy is still likely to happen.
Treating the palsy’s effects is a little more straightforward and usually involves minimizing or stopping the symptoms. Some of the treatments that help the effects of sixth nerve palsy include:
Strabismus surgery can sometimes undercorrect or overcorrect for sixth nerve palsy. In cases like this, the difference is often treatable with prism correction, which can make up for an undercorrection or reverse an overcorrection.
The recovery time after treatment varies. Your healthcare provider can tell you more about what you should expect in your particular case.
Some treatments work immediately and offer relief from symptoms. Patching is an example of this, as it stops double vision by blocking vision in one eye. Prism correction may also provide quick improvements, but it may take days or weeks — depending on the degree of correction — to fully adjust to the change.
Sixth nerve palsy happens unpredictably. The conditions that can cause it don’t always do so, and it often happens for unknown reasons. That means it’s not preventable. You can reduce your risk of developing it from certain causes, though. Examples include:
Sixth nerve palsy isn’t usually dangerous, but it’s still disruptive. It can interfere with school, work, hobbies, social activities and more. It can also feel unpleasant. You might experience dizziness, nausea, headaches and more.
If you experience symptoms of sixth nerve palsy, especially an inability to turn your eyes outward (or in any forward-facing direction), you should talk to a healthcare provider. Most of the time, sixth nerve palsy is a minor concern. But sometimes it happens because of a much more dangerous condition. The best way to increase your odds of a good outcome is to get a diagnosis and treatment sooner rather than later.
Sixth nerve palsy can have a variable duration. Some causes, like migraines, may last only hours. Other causes may last longer, between three and six months. In some cases, it’s a permanent condition. Your healthcare provider is the best person to tell you what’s likely in your case and what you can do to limit how long the condition affects you, or how to adapt to its effects.
The outlook for sixth nerve palsy is good overall. For most people, it’s a temporary condition that’ll go away on its own or with treatment of the underlying cause(s).
In some cases, though, sixth nerve palsy happens because of more serious conditions. That’s more likely when it happens in someone under age 50, and/or if it affects both eyes. Regardless, it’s always a good idea to get medical care if you have the symptoms of sixth nerve palsy. Earlier diagnosis and treatment can make a difference between a full recovery and long-term (or even permanent) effects.
If you have sixth nerve palsy, your healthcare provider will guide you on managing it and the condition(s) that cause it (if any are identifiable). It’s important to follow their guidance, particularly when it comes to managing the symptoms. Wearing eye patches, filters or other corrective items is important because it can help you recover faster and minimize unpleasant symptoms.
You should also see your provider as recommended for follow-up visits so they can track any changes and modify your treatment if necessary. Sixth nerve palsy isn’t an emergency, but it is a condition that you should get diagnosed and treated without delay.
Some questions you may want to ask your healthcare provider include:
A note from Cleveland Clinic
Sixth nerve palsy is a condition that can disrupt your life, but it’s usually treatable and temporary. However, it’s important to get diagnosed and treated sooner rather than later. Talk to a healthcare provider if you have trouble moving your eyes outward (or in any direction). Doing that can improve the odds of a positive outcome. That way, you can look forward to more important things, rather than have your gaze limited by the effects of this condition.
Last reviewed on 12/19/2023.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy