Double Vision (Diplopia): Common Causes and Treatment Options

Ever glanced at a friend and suddenly seen two of them? While it might sound amusing, double vision — known scientifically as diplopia — can be a disconcerting experience. Double vision is an issue that many people face, but it can have a wide range of causes. Whether caused by a simple eye muscle imbalance or a more serious underlying condition, understanding the reasons behind double vision can be key to finding relief.

Read on to find out more about what double vision is, different causes and possible treatments that may help restore your vision.

What Is Double Vision?

Also called diplopia, double vision occurs when you see an object twice in your vision (or sometimes even multiple times).¹

Types

There are two main types of double vision:¹

• Monocular diplopia. Only one eye is affected, so you may not notice the double vision if both eyes are open. This means the issue is most likely related to light somehow getting distorted by your eye.
• Binocular diplopia. Both eyes are affected, so you'll notice double vision when both eyes are open. This means your eyes aren't aligned and focusing together. This can sometimes have neurological causes.

In addition to monocular vs. binocular, double vision can be categorized by how the images appear. Vertical diplopia means images are on top of each other vertically. If the images are side-by-side, this is called horizontal diplopia. A rotated double image is called rotational diplopia.²

Symptoms

When you have double vision, you'll see an image twice in your vision. The images might overlap each other or be separate. The double image might be in your vision constantly, or it may come and go (such as when you're tired).³

This condition can even cause you to see more than two images of the same object. Typically, one of the images will be clearer than the rest. Sometimes you may only notice the issue when you're looking far into your peripheral vision, or far up or down.¹

Certain symptoms alongside double vision might point to a serious underlying condition, such as a neurological issue. Symptoms to watch for include:¹

• Clumsiness
• Dizziness
• Eye bulging
• Eye pain
• Headaches
• Paralysis
• Speech issues
• Swallowing issues
• Weakness

Even if you don't have these symptoms, you should still see a doctor right away if you develop any form of double vision.¹

What Causes Double Vision?

Double vision can be caused by a wide range of conditions. Sometimes it's simply a problem with the eye itself; other times it might be a neurological issue or it could be a symptom of an underlying disease.³

Although some of the causes can be benign, it's important to see a doctor right away if you notice a change in your vision to ensure a more serious health issue isn't happening.

1. Cornea problems

Your cornea is a clear layer over the front of your eye that helps focus light. Issues with the cornea can lead to double vision. Some examples include:⁴

• Astigmatism
• Corneal scarring¹
• Dry eyes
• Infections that affect the cornea, like shingles
• Keratoconus (the cornea is cone-shaped rather than round)¹

Cornea issues are often the underlying cause of monocular diplopia.¹

2. Eye muscle problems

Your eye is controlled by six muscles. Issues with these can lead to double vision because your eyes may no longer be able to coordinate their movements. Two examples include:⁴

• Strabismus (crossed eyes). This occurs when one of your eye muscles is weak or paralyzed.
• Graves' disease. This thyroid condition can impact your eye muscles and lead to vertical double vision.

3. Lens problems

Your eye lens, located behind the pupil, helps focus light onto your retina properly. If you have an issue with your lens, it can lead to double vision.⁴

Cataracts, for example, are a common lens problem that can not only impact your overall vision but also lead you to see double.⁴ A dislocated lens can also create double vision.¹

4. Nerve problems

If you develop issues with the nerves that connect your brain and eye muscles, this can also cause double vision. Several illnesses can cause this type of nerve damage, such as:⁴

• Diabetes
• Guillain-Barre syndrome
• Multiple sclerosis
• Myasthenia gravis
• Nerve paralysis¹
• Convergence insufficiency (CI). Sometimes nerve issues can cause trouble maintaining binocular focus on an object near you. However, diseases and other issues can also cause CI.⁵

5. Brain and neurological issues

Whether caused by accidents or illnesses, neurological issues or brain damage can also lead to double vision. These can range widely from less serious causes, like migraines, to life-threatening conditions like a brain aneurysm, stroke or tumor.⁴

Ocular migraines are a particular type of migraine that cause visual disturbances like double vision, flashing lights or temporary vision loss in one or both eyes. They typically don't come with a headache and may resolve in about 30 minutes.⁶

6. Giant cell arteritis

Giant cell arteritis (also called temporal arteritis) is a condition that causes the arteries in your temples to become inflamed, sometimes leading to double vision, blurry vision, dizziness, headaches, fatigue and vision loss.⁴

7. Other illnesses or diseases

Many other illnesses and conditions can cause diplopia. Some are serious health concerns and others can be alleviated with rest or other mild treatments. Examples include:

• Digital eye strain. If you look at a screen for too long without breaks, your eyes can become strained. This can lead to double vision, dry eye, blurry vision, sore eyes, shoulder pain and headaches.⁷
• Botulism. This toxin can attack nerves and muscles, causing double vision and other serious symptoms like vomiting and difficulty swallowing or even breathing.⁸

Diagnosing Double Vision

Because double vision can have so many potential causes, your doctor will need to do a thorough examination and ask about your medical history and symptoms to diagnose you.¹

Your eye exam may also involve:¹

• Checking for eye bulging
• Following your doctor's finger with your eyes to check for muscle weakness⁹
• Seeing how your pupils respond to light
• Using special devices to examine your eyes' internal structures
• Using a tool shaped like a prism to see how far misaligned your eyes are⁹

Your doctor will also want to know if you have any symptoms that might point to a specific underlying cause, like numbness, weakness, trouble swallowing or dizziness.¹

Depending on what your doctor suspects, they may suggest additional tests, such as:

• An MRI or a CT scan to look for abnormalities¹
• A thyroid blood test if Graves' disease is suspected¹
• A blood test for Lyme disease⁹
• Other blood tests, such as looking for an antibody commonly seen in myasthenia gravis³

Treatment for Double Vision

The treatment for double vision will depend heavily on the cause and can range from non-surgical therapies to surgeries or medication to treat an underlying disorder. In many cases, vision can be restored with vision therapy or other treatments.

Non-surgical vision therapy

For many types of double vision, vision therapy might be an option.

• Eye exercises. If you have convergence insufficiency, for example, you may start with exercises like focusing on objects that pull your eyes inward to the direction of your nose.⁵
• Occlusion therapy. You may be asked to wear an eye patch over one eye until the problem resolves.¹⁰
• Prism glasses. This can help correct double vision, but you may need to wear prism glasses for several months (or longer). You'll either have a thin Fresnel prism attached to your lenses or you may get special-made glasses with a prism.¹⁰
• Longer vision therapy. Some people may be prescribed individualized vision therapy with an optometrist for six to nine months depending on the case.²

Medications

Sometimes you may need medication to help with the underlying cause of your disease. Depending on the cause, this might be coupled with vision therapy.

If your double vision is caused by Graves' disease, for example, you'll need to treat your thyroid issue first. Then, you may need over-the-counter eye drops, steroids or even radiation to reduce eye swelling caused by Graves'.¹¹

Surgery

Sometimes you may start with vision therapy, and if that doesn't help, you may need surgery.⁵ In other cases, surgery may be needed based on the cause of your double vision. For example, people with Graves' disease may need orbital decompression surgery to help ease pressure on their optic nerve.¹¹

Tips to Prevent Double Vision

Not all causes of double vision can be prevented, but you can lower your overall likelihood of developing the condition by taking some precautions:¹²

• Wear protective goggles or headgear if your work or sport brings the chance of eye injury.
• Work with your doctor on controlling your blood sugar if you have diabetes.
• Wear a seat belt to reduce the chances of head trauma in an accident.
• Maintain a healthy diet for eye health.¹³ Foods high in zinc, beta-carotene, omega-3s, vitamins A, C and E, lutein, antioxidants and fiber may help.¹⁴
• Consider vitamin B12 supplements. Observational studies indicate that B12 may slow cataract development, but not all doctors agree supplements are needed. Speak to your eye doctor about your specific situation.¹³

Frequently Asked Questions About Double Vision

Do you still have questions about double vision? Read these answers to commonly asked questions about this eye condition.

CareCredit Credit Card Financing for Double Vision

Whether you’re paying for eye surgery or getting an eye exam, the CareCredit credit card can help you pay for care where your insurance leaves off.* Use our Acceptance Locator to find a vision specialist near you that accepts CareCredit. Continue your wellness journey by downloading the CareCredit Mobile App to manage your account, find a provider on the go and easily access the Well U blog for more great articles, podcasts and videos.

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Author Bio

Stephanie Dwilson specializes in science journalism, breaking news and animal health and is a business owner, non-practicing attorney and writer.