What is diplopia or double vision?

In medicine, double vision is known as diplopia and is described as the simultaneous perception of two images of a single object. The two images can be shifted from each other horizontally, vertically or diagonally; they can also be rotated.


Diplopia is the result in most cases of incoordination in the movement of the extrinsic muscles of the eyeball, the group of muscles that control eye movement. The two eyes still function, but they cannot move in a coordinated fashion to focus on an object.

Dysfunction of the extrinsic eye muscles can be caused by mechanical problems, changes in the neuromuscular junction, or problems with cranial nerves III, IV or VI as well as the visual cortex. The range of associated diseases and conditions is very wide and includes ophthalmic, infectious, neurological, autoimmune, cancer and some systemic diseases. For example:

abscesses Diabetes Drugs eg fluoroquinolones and psychotropics Brain tumor anisometropia Guillain-Barré syndrome keratoconus Multiple sclerosis Lyme disease orbital myositis Sinusitis Strabismus Botulism alcohol intoxication

As diplopia can be a sign of a systemic disease, including neurological processes, it is advisable to see a doctor if it appears, especially if pain also appears. In addition to double vision, diplopia often affects the perception of balance, coordination of movements, and other skills, for example, reading.

types of double vision

Classification of double vision is one of the first steps in diagnosing diplopia. The first major classification is whether it is binocular or monocular, that is, knowing which symptoms affect each eye separately and whether double vision requires both eyes (binocular) or if it also appears with the eye covered (monocular).

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Binocular: Binocular diplopia occurs with both eyes open, if one of the two is covered, it disappears. It is due to strabismus, both esotropic (inward) and exotropic (outward), when each eye receives the image in different parts of the retina. In children it is common for the brain to suppress the image of one eye, which is why diplopia is rare in childhood strabismus but common in adults. monocular: Monocular diplopia is double vision with only one eye. There is also monocular polyopia, which is the perception of double vision in each eye independently, which causes the perception of more than two images of the same object if both eyes are open. Monocular diplopia is much less common than binocular diplopia and is more often due to causes of a benign nature such as keratoconus, lens subluxation or in some cases astigmatism. Serious causes include damage to the anterior visual cortex. Temporary: Temporary binocular diplopia may be due to alcohol intoxication and the effect of psychoactive drugs such as benzodiazepines, opioid drugs, or some antiepileptic drugs. It can also be due to concussion and other mechanical causes. voluntary: Some people are able to misalign their eyes voluntarily, for example by forcing the focus to the center (crossed eyes) or focusing on objects behind other closer objects. In these cases, diplopia does not pose any harm or problem.


Treatment of diplopia depends on the specific condition causing it, and in any case, diagnosing and treating the underlying cause is essential. Some general guidelines include eye exercises, covering one of both eyes, correction with prisms, or surgery in severe cases.

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