Double Vision Symptoms, Causes and Treatment
Learn why double vision should be taken seriously and the complications it can lead to if left untreated.
Diplopia, better known as double vision, is a visual symptom that can be minor or serious. Many of us take for granted our ability to open our eyes and see a single, clear image. It is an automatic function of our vision system; everything works together and there is no problem. But when something goes wrong and we begin to see double images, it can be a sign of a serious underlying problem for which medical attention should be sought 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 may only be temporary.
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 them, which will lead to the disappearance of diplopia. For this reason, many people do not seek medical attention for diplopia. It is important to remember that your brain has merely tricked itself into thinking there is not a problem, and that the underlying problem may still be lurking. If you experience double vision, even if it is minor or temporary, you should consider seeing an optometrist, ophthalmologist, or neurologist.
Types of Diplopia
As mentioned above, there are several types of diplopia. Let’s break them down to understand them better.
Binocular Diplopia: With binocular diplopia, double vision is the result of misalignment of the eyes. In this type of diplopia the condition is present when both eyes are open but goes away when one eye is closed.
Monocular Diplopia: With monocular diplopia, double vision occurs in only one eye and is due to a structural problem. This type is less common than the others and is typically due to dry eye syndrome, a scar or other irregularity on your cornea, a cataract, or significant uncorrected astigmatism. How this type of double vision is treated depends on the cause.
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, for example by 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, you may suffer from one of the four types of diplopia. The best way to determine this is to consult with your eye care provider.
What is Convergence Insufficiency?
Convergence insufficiency usually occurs with eye strain and headaches, such as after reading for an extended period. For example, when focusing on a book, your brain normally causes both eyes to cross inward just slightly. In convergence insufficiency, your eyes have difficulty keeping the focus on the book as they get tired, which may result in blurry or doubled vision. Besides double vision, additional symptoms of convergence insufficiency may include poor concentration; trouble remembering things; headaches; eyestrain; motion sickness; words that move, jump, swim, or float on the page; and sleepiness while reading. Eye exercises can improve double vision caused by convergence insufficiency.
Let’s review other possible causes of double vision.
Causes of Double Vision
As mentioned above, diplopia does not just happen. Here is a breakdown of possible causes for double vision.
Cornea problems: Our cornea is the clear outermost disc that covers the eye and allows light in. 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. If the damaged eye is covered with an eye patch, the problem usually 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 movements. Therefore, if one eye’s muscle is weaker than the other, double vision can result. Conditions like Grave’s disease (a thyroid condition) or myasthenia gravis (autoimmune disease) can contribute to extraocular muscle problems.
Nerve problems: Nerves in our eyes carry 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 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 from our eyes. As we just learned, the nerves transfer information from the eyes to the brain. Once the information arrives, the brain takes over and processes the data. Many different problems—such as strokes, aneurysms, increased pressure from trauma, tumors, and migraines—originate in the brain, and these may cause double vision.
Symptoms of Double Vision
Double vision can occur by itself or it may be accompanied by other symptoms. Additional symptoms may include:
- Pain with eye movements, affecting one or both eyes
- Pain around the eyes, such as in the eyebrows or temples
- Droopy eyelids
- Weakness in the eyes
- Misalignment of the eyes, causing a wandering eye or a cross-eyed appearance
Treatment of Double Vision
Binocular double vision may be treated with a prism that bends light to compensate for eye misalignment. Many people have these prisms added to their eyeglasses. In other cases, eye-muscle surgery may be needed. This surgical procedure involves realigning the eyes. Other people benefit from Botox injections; the substance is injected into an eye muscle, thus improving the alignment of the eyes. There are several treatment options available for 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. Treatment may include:
- Vision Therapy (eye exercises and other non-surgical treatments)
- Specialized Prism Glasses
- Specialized Prism Lenses
- Eye Patches
- 4 mg daily of manganese (stimulates the nerve-muscle connection)
- 75 mg daily of Vitamin-B complex (good for nerve function)
Talking to Your Eye Doctor
Here are some questions to ask your eye doctor about double vision:
- What is causing my double vision?
- Which type of diplopia do I have?
- What are my treatment options?
- Based on the severity of my condition, how often should I schedule follow-up visits?
- Besides manganese and Vitamin-B complex, which other nutrients are good for my eyesight?
- Do you provide vision therapy? Do you think I am a good candidate for vision therapy?
- What eye exercises can I do at home to improve my condition?
- How long will it take for my vision to return to normal?
- Will I need to curtail my daily activities?
- J. Weizer, MD; J. Stein, MD, MS “Reader’s Digest Guide to Eye Care” (Quantum Publishing, 2009) 72-74
- J. Anshel, MD “Smart Medicine for Your Eyes” (SquareOne Publishers, 2011) 203-206
- J. Lavine, MD “The Eye Care Sourcebook” (McGraw-Hill Companies, 2001) 116-120