Causes and Treatment of Double Vision (Diplopia)
When the eyes are working properly, each eye sees a slightly different view of the same object. A complex system involving muscles, nerves and the brain puts these two images together to create one true 3D image. When the eyes point or focuses incorrectly, or the visual processing system isn't working properly, you may find yourself seeing two of each object, referred to as double vision otherwise known as diplopia medically.
Occasionally, double vision may be a temporary problem occurring when you are overtired or have consumed a lot of alcohol. Your eyes may have trouble working together and thus your focus splits into two objects. But double vision is often a symptom of a more serious condition. So if you are experiencing double vision that is beyond a symptom of fatigue, it should be taken seriously and you should consult an eye doctor as soon as possible.
Double vision can be a consequence from any part of the visual system not working correctly; from the anterior structures of the eye like the cornea and lens; to posterior structures, to eye muscles, to the brain.
Below are some of the more common causes of double vision.
Corneal surface problems:
When the cornea is not a clear surface to see through, it may cause double vision.
Stroke or brain condition
Double vision may be the first sign of a stroke, brain swelling, aneurysm or tumor, which is why it should be taken very seriously. Sufferers need to rule out these more serious conditions or get them treated urgently. A head injury can also cause double vision to occur suddenly. Your eye doctor may refer you to a specialist such as a neurologist for further tests and treatment.
Cranial nerve palsies
Cranial nerve palsies can cause the eyes to look in separate directions, resulting in double vision. These palsies are often caused by diabetes, but can also be the result of a head injury, tumor, multiple sclerosis, meningitis, high blood pressure or an aneurysm. The diplopia is usually resolved when the underlying condition is treated but some people may require additional help such as vision therapy, special eyeglasses or surgery.
Ghost images can be caused by conditions such as keratoconus (cone-shaped cornea) or corneal dystrophies, when the corneal structure deteriorates. These problems can sometimes be helped with special rigid contact lenses to help resurface the eye, though sometimes surgery is required to insert corneal implants.
Eye herpes and shingles can also cause corneal changes, which can lead to double vision.
Occasionally, double vision is a side effect of refractive surgery such as LASIK. This happens when the surface of the cornea, which is usually smooth, becomes rough and irregular or dry, causing light rays to scatter instead of focusing clearly. The condition often improves over time as the eye heals, and the use of eye drops may help too. (Consult your surgeon or eye doctor before using any over-the-counter drops after surgery.)
Severe dry eye
While they probably don't seem like much, tears are actually an important part of the visual system. They affect how light rays pass through the cornea and are focused, so if you have severely dry eyes, you may find yourself seeing ghost or shadow images. Simple eye drops, punctual plugs, or oral supplements to promote tear production, lid hygiene techniques or a combination of all these treatments can relieve chronic dry eye and, in turn, clear up the double vision.
If an eye’s lens is clouded with a cataract, this can cause incoming light rays to scatter, creating incomplete images, especially when looking at lights. If you wear eyeglasses, getting an anti-glare coating on them may give some temporary relief, but you will likely need cataract surgery to cure the problem long-term.
Other causes of double vision
- Severe migraine
- Eye alignment problems, such as strabismus (crossed eyes)
- Thyroid disorders
- Autoimmune disorders (including Graves' disease and Myasthenia gravis)
Eye Muscle Misalignment
If an eye muscle is weak is one eye, the two eyes will not move in the same alignment, thus creating double vision. Some causes of muscle misalignment are
- Strabismus (crossed eyes)
- Graves disease (a thyroid disorder)
- Myasthenia gravis (an autoimmune disorder)
Certain conditions can damage the nerves that control our eye muscles. Cranial nerve palsies can cause the eyes to look in separate directions, resulting in double vision.
- Multiple Sclerosis (an inflammatory disease that affects the ability of the nerve cells in the brain and spinal cord to communicate with each other.
- Guillain-Barre syndrome (a disorder affecting the peripheral nervous system resulting in progressive muscle weakness)
- Diabetes can also cause muscle weakness
Severe migraines can cause double vision. But double vision may be the first sign of a stroke, brain swelling, aneurysm or tumor, which is why it should be taken very seriously. Sufferers need to rule out these more serious conditions or get them treated urgently. A head injury can also cause double vision to occur suddenly. Your eye doctor may refer you to a specialist such as a neurologist for further tests and treatment.
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