hemianopia
   Also known as hemianopsia. Both terms come from the Greek words hèmi (half), an (not), and opsis (seeing). They translate loosely as 'blindness in one half of the visual field'. Phe-nomenologically, various types of hemianopia can be distinguished. The term homonymous hemianopia refers to a variant affecting both left or both right fields of vision. Homonymous hemianopia is associated primarily with vascular or neoplastic lesions of the optical tract, optic radiation, or occipital cortex. However, it can also occur in rare cases of "ictal blindness. The term heteronymous hemianopia is used to denote a type of hemianopia affecting either both temporal or both nasal fields of vision. Binasal hemianopia is a relatively rare condition. Pathophysiologically, both types of heteronymous hemianopia are associated with compression of the optic chiasm. Etiologically, bitemporal hemianopia can accompany a variety of conditions, such as pituitary tumours, craniopharyngeomas, and aneurysms, whereas binasal hemianopia is attributed primarily to bilateral compression of the optic chiasm by the internal carotid arteries. In addition, both forms of heteronymous hemianopia can be caused by bilateral peripheral conditions such as retinal pathology or glaucoma. In hemianopia superior, the upper half of the visual field is amaurotic; in hemianopia inferior, the lower half. A further distinction is made between positive ('black'), negative ('grey'), and luminous ('white') hemi-anopia. Positive hemianopia is characterized by a black hemifield (hence the name black hemianopia), whereas negative heimanopia is characterized by an amaurotic hemifield of a more neutral hue (hence the name grey hemi-anopia), or the impression that the hemifield is 'missing' (known as hémianopsie nulle in French). The term luminous hemianopia is reserved for a type of hemianopia that can only be seen against a dark background, and which presents as a luminosity. Hemianopia can be complicated by impaired insight into the problem (as in the " Anton-Babinski syndrome) and with "hemianopic hallucinations. Such "visual hallucinations are also referred to as ophthalmopathic hallucinations. See also the entry Charles Bonnet syndrome (CBS).
   References
   Critchley, M. (1953). The parietal lobes. London: Edward Arnold & Co. Freiman, Th.M., Surges, R., Vougioukas, V.I., Hubbe, U., Talazko, J., Zentner, J., Honeg-ger, J., Schulze-Bonhage, A. (2004). Complex visual hallucinations (Charles Bonnet syndrome) in visual field defects following cerebral surgery. Report of four cases. Journal of Neurosurgery, 101, 846-853.
   Pick, A. (1904). The localizing diagnostic significance of so-called hemianopic hallucinations with remarks on bitemporal scintillating sco-tomata. American Journal of Psychology, 15, 586-587.
   Spatt, J., Mamoli, B. (2000). Ictal visual hallucinations and post-ictal hemianopia with anosognosia. Seizure, 9, 502-504.
   Vaphiades, M.S., Celesia, G.G., Brigell, M.G. (1996). Positive spontaneous visual phenomena limited to the hemianopic field in lesions of central visual pathways. Neurology, 47, 408-417.

Dictionary of Hallucinations. . 2010.

Look at other dictionaries:

  • hemianopía — hemianopsia. Ceguera en la mitad del campo visual Diccionario ilustrado de Términos Médicos.. Alvaro Galiano. 2010 …   Diccionario médico

  • hemianopia — Loss of vision for one half of the visual field of one or both eyes. SYN: hemianopsia. absolute h. hemianopsia in which the affected field is totally insensitive to all visual stimuli. SYN: complete h.. altitudinal h. a defect in the visual …   Medical dictionary

  • hemianopia — n. absence of half of the normal field of vision. The commonest type is homonymous hemianopia, in which the same half (right or left) is lost in both eyes. Sometimes the inner halves of the visual field are lost in both eyes, producing a binasal… …   The new mediacal dictionary

  • hemianopía — Eng. Hemianopia Ver hemianopsia …   Diccionario de oftalmología

  • hemianopia — noun hemianopsia …   Wiktionary

  • hemianopia — n. condition causing a loss of perception in half of the visual field, half blindness (also hemianopsia) …   English contemporary dictionary

  • hemianopia — [ˌhɛmɪə nəʊpɪə] (also hemianopsia nɒpsɪə) noun blindness over half the field of vision …   English new terms dictionary

  • hemianopia — hem·i·a·no·pia …   English syllables

  • hemianopia — noun blindness in one half of the visual field of one or both eyes • Syn: ↑hemianopsia • Hypernyms: ↑visual impairment, ↑visual defect, ↑vision defect, ↑visual disorder …   Useful english dictionary

  • altitudinal hemianopia — hemianopia in the upper or lower half of the visual field …   Medical dictionary

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