Visual Lesions Flashcards
Loss of vision is named for
vision field lost (NOT retinal)
Scotoma
small visual field deficit
Anopsia
large visual field deficit
Hemianopsia
1 half of visual field lost
Homonymous
visual field deficit same in both eyes (L visual field)
Heteronymous
visual field deficit in opposite halves (L/R)
Quadrantanopsia
deficit in 1/4 of visual field
Agnosia
visual association cortex lesion
Optic n. lesion
complete blindness in affected eye
Causes for optic nerve lesion
trauma or degenerative disease
Optic Chiasm lesion
Bitemporal heteronymous hemianopsia (tunnel vision)
Causes for Optic Chiasm lesion
pituitary tumor impingement
Early signs of pituitary tumor
bitemporal superior quadrantanopsia
Optic tract lesion
contralateral homonymous hemianopsia
Lateral optic chiasm lesion
ipsilateral nasal hemianopsia
Causes of Lateral optic chiasm lesion
internal carotid artery aneurysm (hard to detect due to binocular vision)
Optic radiation lesion
Contralateral homonymous hemianopsia (loss of ALL fibers on one side fro LGN to visual cortex)
Will optic radiation lesion have a pupillary light reflex?
YES!
Temporal (Meyer’s) Loop Lesion
Upper fibers = Contralateral Superior Quadrantanopsia
Parietal Portion Lesion
Contralateral Inferior Quadrantanopsia
Unilateral Lesion to the primary cortex
Contralateral homonymous hemianopsia EXCEPT MACULAR SPARING
Causes of Unilateral Lesion to the primary cortex
occlusion of the posterior cerebral artery or its calcarine branch
Why is there macular sparing in Unilateral Lesion to the primary cortex
disproportionately large area for fovea and presence of collateral circulation from the MIDDLE CEREBRAL ARTERY
