Double Vision or Ghost Images

If you start seeing double images when your eyes normally work well together, you should usually take this development seriously. While this condition (known as diplopia in our lingo) may be temporary, you should still visit your eye doctor to find out what's going on.

Temporary episodes of double vision can happen for many reasons, including drinking too much alcohol or being overly tired. This type of short-term double vision is usually not cause for worry. But if the double vision is long-lasting or keeps coming back, reasons for it can include:

• Stroke, head injury, brain tumor, brain swelling or brain aneurysm: A head injury, tumor, stroke or related condition can cause double vision that comes on suddenly. After examining you, your eye doctor may refer you to a specialist such as a neurologist or neurosurgeon for further testing and treatment.
   

Double vision can occur when the eyes look in separate directions because of cranial nerve palsies, strabismus or other reasons.

• Cranial nerve palsies: Most cranial nerve palsies (causing the eyes to look in separate directions) happen because of diabetes. Cranial nerve palsies also sometimes result from head injury, tumor, multiple sclerosis, meningitis, high blood pressure, blockage in an artery or aneurysm. Most cranial nerve palsies go away without treatment when the condition that caused them improves. But some people may need vision therapy, surgery or special prism in eyeglasses to help with the double vision.
   
• Cataracts: Cataracts may cause ghost images, usually in one eye only. This is because the clouding of the eye's natural lens that sits behind the pupil (called a cataract) can cause light rays to scatter in different directions, creating multiple but incomplete images, especially when you look at lights. Cataract surgery (removing the natural lens and replacing it with an artificial lens, called an implant) will eliminate this ghost image problem. However, you may find some temporary relief by having a non-glare (anti-reflective) coating on your glasses lenses.
   
• Refractive surgery: If you have had LASIK, PRK, or any refractive surgery to help you see better without glasses or contacts, you may experience some double or ghost imaging because of changes to your corneas (the eye's clear front surfaces). An irregular surface, caused by the surgery itself or by dryness, may cause light rays to scatter instead of focusing properly. This problem usually clears up within weeks or months. But you may need to use eye drops for a while.
   
• Dry eyes: Severe dry eyes, such as Sjogren's syndrome, can cause ghost images due to insufficient or poor quality tears. Many people who suffer from dry eyes can be helped by eye drops (over-the-counter or prescription), punctal plugs, oral supplements or medications, lid hygiene techniques or a combination of all these treatments. It's very important to have a dry eye workup and treatment, if necessary, from an eye doctor who has an interest in this disorder and has kept up to date on the latest diagnosis and treatment methods.
   
• Corneal irregularities: Ghost images can be caused by such conditions as keratoconus (cone-shaped corneas) and corneal dystrophies (deterioration of the corneal structure). These ghost images can be harder to manage. Many corneal irregularities can be helped when you wear special contact lenses or use dry eye treatments such as eye drops or punctal plugs. Some people with this condition may need surgery, such as a corneal transplant or Intacs implants. Your eye doctor can help you figure out the best treatment for your individual problems.

Rather than clearly seeing a double image, you may instead notice only a partial or "ghost image" around or to the side of what you are looking at, especially a light source.

Ghost images, like those created by cataracts, are usually seen by only one eye (monocular double vision). Ghost images also are more common after corneal surgery, like LASIK, PRK or a corneal transplant. Most of these problems disappear when the problem is resolved, such as after cataract surgery or when the refractive surgery heals.
 

Most of us obviously don't expect to see double images. But in truth, the ability to see a single image with two eyes involves a complex system of muscles, nerves and other eye parts. When two eyes correctly and accurately point and focus at the same time, we see only one image of the world. When two eyes point and focus differently from each other, double vision may happen.

Some people are born with eyes that don't work together, a condition called strabismus. Eyes can be crossed inward or turn outward. One eye can even go up while the other goes down. If you have strabismus, you will see double if your brain allows it, because each eye sees a different thing at the same time. But the brain usually adapts by shutting down or ignoring the information from one eye. This is called suppression. Surgery or vision therapy can help many people with strabismus.

Generally, treatments for double vision can include surgery, vision therapy, prism in the glasses prescription or medications. It's important to have a comprehensive eye examination to help determine the cause of the double vision as soon as possible. Your eye doctor may then treat the double vision or send you to a specialist (such as a neurologist or neurosurgeon).

If you have sudden double vision that you ignore and then it goes away over a long time period, this may mean your brain has tuned out one of the images (suppressed it). Although this is certainly more comfortable and bearable for you, it is not a good sign. Suppression may mask a serious problem that needs to be solved. In fact, the condition may be a matter of life or death, such as a brain tumor or aneurysm. So see your eye doctor immediately if double vision develops.

Some conditions causing double vision are difficult, if not impossible, to fix. Some strokes and nerve palsies cause fluctuating double vision that can't be measured accurately enough to correct. In these circumstances, you may need a period of adjustment so that you can learn to live with the symptoms. Your eye doctor can help by prescribing prism, patching one eye for periods of time, fogging parts of your glasses lenses or using special contact lenses. In most cases, your brain will eventually suppress one of the images so you can get on with your life. As with most life changes, patience is a virtue in dealing with such problems!