Double Vision or Diplopia
Reviewed by Dr. Robert J. Esposito
Diplopia, better known as double vision, is a visual symptom that can be minor or serious. Many of us take advantage of opening our eyes and seeing a single, clear image. It's an automatic process that is working within our vision system; everything works together and there is no problem. However, when something goes wrong and we begin to see double images, it could be a sign of a serious underlying problem and medical attention should be sought after immediately.
There are many types of Diplopia, as images can be off horizontally, vertically, or diagonally. The condition can affect one eye or both eyes, and it can be temporary or voluntary.
Suppression plays a major role because the brain naturally tries to avoid double vision. The brain accepts and uses the two separate images, but will eventually suppress one of the images, which will lead to the disappearance of diplopia. Many people accept this process without seeking medical attention. It's important to remember that your brain has tricked itself into thinking there isn't a problem, and that the underlying problem may still be lurking. If you experience double vision, even if it's minor or temporary, you should still consider seeing an optometrist, ophthalmologist, or neurologist.
Types of Diplopia
As mentioned above, there are several types of Diplopia. Let's break down each to understand them better.
Binocular Diplopia - With binocular diplopia, double vision is the result of the misalignment of both eyes due to functional problems within the vision system.
Monocular Diplopia - With monocular diplopia, double vision occurs in only one eye and is due to a structural problem within the vision system. This type is much less common than the others.
Temporary Diplopia - Temporary diplopia is generally due to a traumatic event, head injury, or intoxication by a substance such as alcohol.
Voluntary Diplopia - Many of us have intentionally induced double vision. A great example is when viewing stereograms (optical illusions of depth that are created from a flat, two-dimensional image).
Depending on the underlying condition, and whether it is due to a structural or functional problem with the vision system, you may suffer from one of the four types of diplopia.
Causes of Double Vision
As mentioned above, diplopia doesn't just happen. There is usually a reason or a cause for the double vision. Here is a break down of our vision system, including the cornea, lens, muscles, nerves, and brain, with possible causes for double vision.
Cornea problems - Our cornea is the clear outermost disc that covers the eye and allows in focused light. If a problem occurs within the cornea, it generally causes monocular diplopia. The damage on the surface of the eye distorts incoming light, causing the double vision. Usually, if the damaged eye is covered with an eye patch the problem goes away immediately.
Lens problems - Our lens is located behind the pupil and focuses light onto the retina. One of the most common problems we experience with the lens is cataracts. Cataracts are known to cause double vision and can be corrected with surgery. Lens problems can occur in one or both eyes and may be diagnosed as binocular or monocular diplopia.
Muscle problems - The muscles around our eyes are known as extraocular muscles. The extraocular muscles perform our eye's movements, so if one eye's muscle is weaker than the other, double vision can be the result. Conditions like Grave's disease (a thyroid condition) or myasthenia gravis (autoimmune disease) can contribute to extraocular muscle problems.
Nerve problems - Nerves within our eyes carry the visual data from our eyes to our brain. If these important nerves are damaged, double vision can be the result. There are many different conditions, such as multiple sclerosis and diabetes, that can cause or lead to nerve damage in the eyes.
Brain problems - Our brains do much more than think for us. There are many areas within the brain that help process visual information delivered from our eyes. As we just learned, the nerves transfer information from the eyes to the brain. However, once the information arrives, the brain takes over and continues processing the data. Many different problems originate in the brain, such as strokes, aneurysms, increased pressure from trauma, tumors, and migraines, and these may cause double vision.
Symptoms of Double Vision
Double vision can occur by itself, or accompanied by other symptoms as a result of an underlying problem. Additional symptoms may include:
- Pain with eye movements, affecting one or both eyes
- Pain around the eyes, such as in the eyebrows or temples
- Headaches
- Nausea
- Droopy eyelids
- Weakness in the eyes
- Misalignment of one or both eyes, such as a wandering eye or cross-eyed appearance
Treatment of Double Vision
There are treatment options available to treat double vision. The key is figuring out the underlying cause and treating that problem first. Again, double vision is generally a symptom of another problem, so treatment may include:
- Surgery
- Orthoptics
- Vision Therapy Therapy (eye exercises & other non surgical treatments)
- Medication
- Specialized Prism Glasses
- Specialized Prism Lenses
- Eye Patches
[Page updated 1/2011]
