Double vision (also called diplopia) may be temporary, or long-lasting. It is often visually disturbing and can limit day to day activities like driving, walking down the stairs, and working on the computer. Diplopia may sometimes be misinterpreted as Ghost images and blurriness.
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 strabismus. They will see double if their 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.
Other causes of double vision include:-
- Stroke, head injury, brain tumor, brain swelling or a brain aneurysm. A head injury, tumor, stroke or related condition can cause double vision that comes on suddenly.
- Cranial nerve palsies. Double vision also can be caused by paralysis or loss of coordination of one or more muscles that control the position and teaming of the eyes due to cranial nerve palsy. Cranial nerve palsies can be caused by viral fever diabetes, head injury, tumor, multiple sclerosis, meningitis, high blood pressure, blockage of an artery or an aneurysm.
The above two are causes of binocular diplopia, that is double vision with both eyes open. There is relief from diplopia when one of the eyes is closed.
3. Corneal irregularities. Ghost images can be caused by such conditions
as keratoconus (cone-shaped corneas) and corneal dystrophies (deterioration of the corneal structure).
4. Dry eyes. Severe dry eyes 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, lid hygiene techniques or a combination of all these treatments.
5. Refractive surgery. If you have had 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. An irregular corneal 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.
6. Cataract or lens abnormality. Cataracts may cause ghost images, usually in one eye only. This is because the clouding of the eye's natural lens and can cause light rays to scatter in different directions, creating multiple but incomplete images, especially when you look at lights. Sometimes severe blunt trauma to the eye can cause tilting of the
lens, causing monocular diplopia.
Lens surgery usually will eliminate this ghost image problem.
Generally, treatments for double vision can include surgery, vision therapy, prism glasses or medications.
It’s important to have a comprehensive eye exam to help determine the cause of the double vision as soon as possible.
If you have a 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 could be masking a serious problem that needs to be solved.