Diplopia (Double Vision) and Treatment Effectiveness
Medically reviewed by Andrew Greenberg, MD
In diplopia (double vision), you see more than one image at the same time. This may occur in just one or both eyes. It may come on suddenly and be temporary, or it can be something you've experienced for a while. It all depends on the underlying cause.
In this article, you'll learn the symptoms of double vision and how these may vary depending on the type, whether treatment can help restore your vision, what may be causing the condition, potential complications, and more.
Illustration by Mira Norian for Verywell Health
Symptoms of Diplopia Subtypes
The symptoms you experience will depend upon the type of diplopia you are dealing with. That begins with determining whether the double vision affects one or both eyes.
In monocular diplopia, just one eye is affected. When just that eye is open, you may see a ghost image. Most of the time, that ghost image is caused by something in the eye rather than a condition in the brain (neurological).
If you experience double vision only when both eyes are open, there's a likelihood of a neurological cause. If you have double vision in both eyes (binocular), this may go away when you shut one of your eyes since only one image will then reach the brain.
Binocular diplopia may occur because one eye is looking at one image and the other at a slightly different one. It may also occur only when you move your eyes in a certain direction, such as side to side or up and down.
Does Treatment Correct Diplopia?
Sometimes, diplopia resolves on its own, but you shouldn't count on this. Fortunately, there are a variety of approaches to correcting double vision.
In cases where diplopia is caused by an underlying issue such as hyperthyroidism (an overactive thyroid) or multiple sclerosis (an autoimmune condition affecting the nervous system), medication to help control the condition may also resolve your double vision.
If you have binocular double vision caused by seeing two conflicting images, then your eye doctor may recommend occlusion therapy. This involves patching one eye or blocking off one of the lenses on your glasses. This only allows one image through and can be continued until the double vision dissipates and the patch is no longer needed.
Your eye doctor may recommend getting Botox (botulinum toxin) injections in the muscles of the stronger eye so these muscles aren't as dominant. This gives the muscles of the other eye a chance to catch up. Depending on the issue, this may be a temporary approach or ongoing.
If the eyes are misaligned due to muscle issues, muscle surgery may be recommended in some instances.
Causes of Diplopia
Double vision can come from different parts of the eye, the muscles, the nerves, and even the brain. Here are the leading possibilities for what may be at the root of your double vision:
Lens problems: The lens focuses light rays onto the light-sensitive retina. But sometimes, something gets in the way of this. If you develop a cataract (the lens becomes clouded), it's not uncommon to develop double vision, which may continue until the cataract is removed.
Corneal issues: The clear dome over the top of the eye (cornea) can sometimes become damaged. Conditions that may impact the corneal surface and cause double vision include dry eye, scarring, infections, and the development of astigmatism, where the cornea is no longer completely round.
Eye muscle problems: Eye muscles shift your gaze, either up or down or left and right. If one set of eye muscles is weaker or becomes paralyzed, the eyes won't move in concert, and you may end up with double vision. Sometimes, a muscle malady may cause strabismus (misaligned eyes). If you notice that you have vertical double vision where one image is above the other, this may result from Graves' disease, a thyroid disorder that impacts the muscles of the eyes. If you have horizontal double vision, this usually relates to the medial or lateral rectus muscle. Muscle weakness that causes double vision that is worse at a distance is likely due to a sixth nerve palsy causing some loss of function because this indicates trouble with the eyes diverging. Meanwhile, if the double vision is worse when viewing some closeup, the trouble involves bringing the eyes together and likely involves a medial rectus palsy.
Cranial nerve issues: The cranial nerves that send signals from the eyes to the brain can impact eye movement and lead to double vision. Eye nerves can be weakened or damaged by conditions where the immune system attacks them, such as Guillain-Barre syndrome, multiple sclerosis, and myasthenia gravis. If you have diabetes, your nerves can also be affected by high blood sugar.
Brain issues: It's up to the brain to decipher the visual images that come from the eyes. Conditions such as migraine headaches, tumors, aneurysms (outpouchings of blood vessels), strokes, infections, or head trauma can possibly be the cause.
The most common cause of diplopia usually depends on age. When a person over 65 complains of monocular diplopia, the usual diagnosis is cataracts or dry eyes. When that same person complains of binocular diplopia, the cause may be cranial nerve palsy due to diabetes or hypertension.
The cause of diplopia can vary in younger people—commonly, it is dry eyes or ophthalmic migraine. More information about the length of time a problem occurs or whether it fluctuates makes a major difference in the diagnosis.
Sudden Symptoms
While double vision may be a chronic issue for you, in other cases, it may appear suddenly. This can be scary and should be checked out, but remember that you may be having a stress reaction or just be extremely tired.
Still, you should have this checked out to ensure that there is not something more serious going on. The fact that the double vision has come on suddenly should raise a red flag. It may indicate an issue with the brain that needs to be looked at more closely. Other red flags may be headaches with vision problems or vision loss unrelated to issues with the eye itself.
Also, note any other symptoms. Something like a stroke, for example, can come on suddenly. In addition to visual changes like sudden double or blurred vision, some may experience severe headaches, balance difficulties, and numbness on one side. Anyone experiencing symptoms such as these should immediately call 911.
Eye Exam to Diagnose Diplopia
When you visit an eye doctor to assess your double vision, they will first determine whether it is due to an issue with one eye or both. If the double vision appears to be coming from just one eye, then they will look at the structures of the eye under magnification at the slit lamp to get a better look at what may be causing the diplopia in the eye.
As part of the eye exam, the eye doctor will also consider how your eye muscles function by asking you to look side to side and up and down.
They will also determine if your eyes are misaligned by shining a light into them as you look through the prism. In addition, they will give you a neurological exam to determine whether your brain may be the source of your diplopia.
The eye doctor will look for any signs of a muscular disorder, such as eyelid drooping, which can occur with a condition such as myasthenia gravis or muscular dystrophy.
They may also order a blood test to see if an underlying condition (such as Graves' disease) is causing your double vision.
You may also need to undergo magnetic resonance imaging (MRI) to determine whether a tumor or nerve inflammation is the cause of the problem.
Treatment to Correct Temporary Double Vision
In some cases, double vision may be caused by a medical condition. While trying to resolve this, your vision may fluctuate, and an eye doctor may prescribe a temporary fix to help you function in the meantime.
A prism is a pie-shaped piece of glass or plastic that can bend light to bring two images together. They may recommend attaching a press-on prism to one or both of your glasses' lenses to resolve the issue temporarily.
Complications and Ongoing Symptoms
In addition to contending with double vision, without treatment, you may also find yourself dealing with ongoing symptoms such as the following:
Nausea
Headaches
Pain around the temples or eyebrows
Eye weakness
Experiencing pain when moving your eyes
If you experience ongoing double vision, you should seek answers. In many cases, these symptoms can be treated and alleviated.
Summary
Double vision can occur in one or both eyes. It may be caused by something in the eye itself, by the muscles or nerves involved, or even by the brain. While having double vision does not usually mean anything is seriously wrong, particularly if it comes on suddenly, it is important to promptly get it checked.
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