Hemianopsia ( ancient Greek ἡ μι- - semi- + ἀν- - negative prefix + ὄψις - vision) - double-sided blindness in half of the visual field [1] . Hemianopsia is caused by damage to the visual system at the level of the chiasm of the optic tract, the optic tract or the visual cortex .
Hemianopsia | |
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Homonymous hemianopsia | |
ICD-10 | H 53.4 |
ICD-9 | 368.46 , 368.47 |
Mesh |
Terminology
Hemianopsia with the loss of the same (right or left) half of the visual fields is called homonymous, the opposite (two nasal or two temporal) halves - heteronymous. The loss of the temporal halves of the visual field is called heteronymous bitemporal hemianopia , the loss of the nasal halves is called the binasal hemianopia . In addition to the complete loss of half of the visual fields, there may be partial, quadrant (quarter - upper or lower) anopsia, hemianopic scotoma (blind spot) [2] . Preservation of one of the halves of the visual field is defined as hemiopia (ie, the eye, characterized by right-sided hemianopia, simultaneously has left-sided hemiopia, and vice versa) [3] .
Topics of defeat
Partial damage to the intersection of the optic nerves is manifested by hemianopic scotoma . Heteronymous (dissimilar) bitemporal hemianopsy is observed when the central region of the intersection of the optic nerves is affected (due to pituitary tumors, hydrocephalic expansion of the funnel, etc.). Binasal hemianopsia is less common with lesions of the outer chiasma fibers (due to basal inflammatory processes or bilateral aneurysms of the intracranial regions of the carotid arteries ).
Homonymous hemianopsia is observed with damage to the optic tract, the external articular body , the posterior pedicle of the internal capsule, the visual radiance, or the area of the spur sulcus. In this case, the right-sided lesion causes left-sided homonymous hemianopia, and vice versa.
Upper homquamous hemianopsy occurs when the ventral part of the visual path or the lower lip of the spur sulcus is damaged, the lower quadrant of the dorsal part of the visual path or the upper lip of the spur sulcus.
Bilateral lesion of the visual cortex (occipital lobes) is manifested by horizontal upper or lower hemianopia or bilateral hemianopsia with preservation of central vision [2] .
Illustrations
Normal vision
Homonymous hemianopsia
Heteronymous Binasal Hemianopia
Heteronymous Bitemporal Hemianopia
Hemianopsy variants in accordance with the topography of the lesion
Notes
- ↑ Hemianopsia // Brockhaus and Efron Encyclopedic Dictionary : 86 tons (82 tons and 4 extra). - SPb. , 1890-1907.
- ↑ 1 2 Hemianopsia Archive dated December 30, 2009 on Wayback Machine
- ↑ Hemiopia Unsolved . Great Soviet Encyclopedia. Archived April 5, 2013.
See also
- Bitemporal hemianopsia
- Binasal hemianopsia
- Visual system
- Optic nerve
- Scotoma