Diplopia


Diplopia
Diplopia
Classification and external resources

Photo showing how a patient experiences diplopia
ICD-10 H53.2
ICD-9 368.2
DiseasesDB 31225
eMedicine oph/191
MeSH D004172

Diplopia, commonly known as double vision, is the simultaneous perception of two images of a single object that may be displaced horizontally, vertically, or diagonally (i.e. both vertically and horizontally) in relation to each other.[1] It is usually the result of impaired function of the extraocular muscles (EOM's), where both eyes are still functional but they cannot converge to target the desired object.[1] Problems with EOM's may be due to mechanical problems, disorders of the neuromuscular junction, disorders of the cranial nerves (III, IV, and VI) that stimulate the muscles, and occasionally disorders involving the supranuclear oculomotor pathways or ingestion of toxins.[2]

Diplopia is often one of the first signs of a systemic disease, particularly to a muscular or neurological process,[3] and it may disrupt a person’s balance, movement, and/or reading abilities.[1][4]

Contents

Classification

Binocular

Binocular diplopia is double vision arising as a result of the misalignment of the two eyes relative to each other, such as occurs in esotropia or exotropia. In such a case while the fovea of one eye is directed at the object of regard, the fovea of the other is directed elsewhere, and the image of the object of regard falls on an extra-foveal area of the retina.

The brain calculates the 'visual direction' of an object based upon the position of its image relative to the fovea. Images falling on the fovea are seen as being directly ahead, while those falling on retina outside the fovea may be seen as above, below, right or left of straight ahead depending upon the area of retina stimulated. Thus, when the eyes are misaligned, the brain will perceive two images of one target object, as the target object simultaneously stimulates different, non-corresponding, retinal areas in either eye, thus producing double vision.

This correlation of particular areas of the retina in one eye with the same areas in the other is known as retinal correspondence. This relationship also gives rise to an associated phenomenon of binocular diplopia, although one that is rarely noted by those experiencing diplopia: Because the fovea of one eye corresponds to the fovea of the other, images falling on the two foveas are 'projected' to the same point in space. Thus, when the eyes are misaligned, the brain will 'project' two different images in the same visual direction. This phenomenon is known as 'confusion'.

The brain naturally guards against double vision. In an attempt to avoid double vision, the brain can sometimes ignore the image from one eye; a process known as suppression. The ability to suppress is to be found particularly in childhood when the brain is still developing. Thus, those with childhood strabismus almost never complain of diplopia while adults who develop strabismus almost always do. While this ability to suppress might seem an entirely positive adaptation to strabismus, in the developing child this can prevent the proper development of vision in the affected eye resulting in amblyopia. Some adults are also able to suppress their diplopia, but their suppression is rarely as deep or as effective and takes longer to establish, and thus they are not at risk of permanently compromising their vision. Hence, in some cases diplopia disappears without medical intervention, but in other cases the cause of the double vision may still be present.

Monocular

More rarely, diplopia can also occur when viewing with only one eye; this is called monocular diplopia, or, where the patient perceives more than two images, monocular polyopia. In this case, the differential diagnosis of multiple image perception includes the consideration of such conditions as corneal surface keratoconus, a structural defect within the eye, a lesion in the anterior visual cortex (rarely cause diplopia, more commonly polyopia or palinopsia) or non-organic conditions. Also, sub-luxation of the lens.

Temporary

Temporary diplopia can be caused by alcohol intoxication or head injuries, such as concussion. If temporary double vision does not resolve quickly, one should see an ophthalmologist immediately. It can also be a side effect of the anti-epileptic drugs Phenytoin and Zonisamide, and the anti-convulsant drug Lamotrigine, as well as the hypnotic drug Zolpidem and the dissociative drugs Ketamine and Dextromethorphan. Temporary diplopia can also be caused by tired and/or strained eye muscles, or by one crossing their own eyes at will. If diplopia appears with other symptoms such as fatigue and acute or chronic pain, the patient should see a doctor immediately.

Voluntary

Some people are able to consciously uncouple their eyes, inducing double vision on purpose. These people do not consider their double vision dangerous or harmful, and may even consider it enjoyable. It makes viewing stereograms possible.

Causes

Diplopia has a diverse range of ophthalmologic, infectious, autoimmune, neurological, and neoplastic causes.

Treatment

The appropriate treatment for binocular diplopia will depend upon the cause of the condition producing the symptoms. Efforts must first be made to identify and treat the underlying cause of the problem. Treatment options include eye exercises[1], wearing an eye patch on alternative eyes[1], prism lenses[6], and in more extreme situations, surgery[4] or botulinum toxin.[7]

See also

References

  1. ^ a b c d O'Sullivan, S.B & Schmitz, T.J. (2007). Physical Rehabilitation. Philadelphia, PA: Davis. ISBN-13:978-0-8036-1247-1.
  2. ^ Blumenfeld, Hal (2010). Neuroanatomy through Clinical Cases. Sunderland MA: Sinauer. ISBN 978-0-87893-058-6.
  3. ^ Rucker, JC. (2007). Oculomotor disorders. Semin Neurol., 27(3):244-56.
  4. ^ a b Kernich, C.A. (2006). Diplopia. The Neurologist, 12(4): 229-230
  5. ^ http://www.merck.com/mmpe/sec09/ch098/ch098e.html
  6. ^ Phillips PH. (2007). Treatment of diplopia. Semin Neurol., 27(3):288-98.
  7. ^ Taub, M.B. (2008). Botulinum toxin represents a new approach to managing diplopia cases that do not resolve. Journal of the American Optometric Association, 79(4): 174-175
  • ^ Cassin, B. & Solomon, S. (1990) Dictionary of Eye Terminology. Gainesville, Florida: Triad Publishing Company

External links


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Look at other dictionaries:

  • Diplopía — Saltar a navegación, búsqueda Diplopía Clasificación y recursos externos Aviso médico CIE 10 H53.2 …   Wikipedia Español

  • diplopía — f. oftalm. Alteración de la percepción de las imágenes en forma de visión doble. Puede producirse una diplopía binocular, cuando las imágenes procedentes de cada ojo no se fusionan y el sujeto forma dos imágenes, una procedente de cada ojo; la… …   Diccionario médico

  • Diplopia — Di*plo pi*a, Diplopy Dip lo*py, n. [NL. diplopia, from Gr. ? double + the root of ? sight: cf. F. diplopie.] (Med.) The act or state of seeing double. [1913 Webster] Note: In crossed or heteronymous diplopia the image seen by the right eye is… …   The Collaborative International Dictionary of English

  • diplopia — s. f. Duplicação mórbida da imagem dos objetos na visão. = DIPLOPSIA …   Dicionário da Língua Portuguesa

  • diplopía — (Del gr. διπλόος, doble, y ὄψ, ὀπός, vista). f. Med. Fenómeno morboso que consiste en ver dobles los objetos …   Diccionario de la lengua española

  • diplopia — [dip lō′pē ə] n. [ModL < Gr diploos, double + ōps (gen. ōpos); akin to ops, EYE] a vision disorder in which a single object appears double; double vision diplopic [dipläp′ik] adj …   English World dictionary

  • diplopia —    The term diplopia comes from the Greek words diploös (double) and opsis (seeing). It translates as double vision. The ensuing coexistence ofsim ilar images within the field of vision is called * multiplication. Diplopia can be divided into two …   Dictionary of Hallucinations

  • Diplopía — (Del gr. diploos, doble + ops, opos, vista.) ► sustantivo femenino MEDICINA Enfermedad ocular que consiste en ver dobles los objetos, provocada con frecuencia por una anomalía de los músculos del ojo. SINÓNIMO [visión doble] * * * diplopía (del… …   Enciclopedia Universal

  • diplopía — Eng. Diplopia Percepción de dos imágenes de un solo objeto. Vista doble. Visus duplicatus. Poliopía binocular. Diploscopia. Visión doble. Ambiopía …   Diccionario de oftalmología

  • diplopia — ż I, DCMs. diplopiapii, blm med. «widzenie podwójne, wywołane niesprawnością mięśni zewnętrznych gałki ocznej lub pasmowatym zmętnieniem soczewki» Diplopia jednooczna, obuoczna. ‹z gr.› …   Słownik języka polskiego