Ch 7: Clinical Correlates pg 185-187 Flashcards
visual field deficit
anopsia
loss in half of a field
hemianopsia
loss in a quarter of a field
quadrantanopsia
lesion in part of the visual pathway originating in nasal retina will result in deficits in what visual field?
temporal
*and vice versa…
lesion in front of the optic chiasm will result in visual field defects that are….
monocular and ipsilateral to side of lesion
ex. complete R optic nerve lesion–>loss of vision in R eye
small spotlike deficits in the visual field (scotomas) of that eye result from lesions in…
retina
papilledema, optic neuritis (MS), blockage of central artery of retina can cause lesions where, and what signs?
optic nerve–>anopsia in ipsilateral eye
aneurysm of internal carotid artery can cause what signs..
ipsilateral nasal hemianopsia (will compress the axons of the optic nerve that arise form the temporal part of the retina)
ex. compression of temporal retinal axons on R–>R nasal hemianopsia
complete lesion of fibers that cross the optic chiasm can result in…
bitemporal heteronymous hemianopsia: loss of vision from both R and L temporal fields (only temporal axons cross)
pituitary adenoma can cause…
bitemporal superior quadrantanopsia
(axons conveying visual info from superior temporal quadrants cross inferiorly in the optic chiasm and the pituitary will compress it from below)
*may eventually progress to bitemporal heteronymous hemianopsia
craniopharyngioma or aneurysm at junction of ACA and anterior communicating artery can cause…
bitemporal inferior quadrantanopsia, initially
compresses from above the optic chiasm
lesions in visual pathways past the chiasm will cause visual field deficits that are…
contralateral, homonymous (meaning same side in both eyes), and binocular
complete lesion of left optic tract results in…
right (contralateral) homonymous hemianopsia
*can’t see right temporal hemifield or left nasal hemifield
occlusion of the anterior choroidal artery, main blood supply to the optic tract, or the thalamogeniculate artery (a branch of the PCA that supplies the LGN) can result in…
contralateral homonymous hemianopsias
pupils that are unreactive to light, but contract briskly in near response
Argyll Robertson pupils
Argyll Robertson pupils are ocmmonly seen in patients with..
tabes dorsalis (neurosyphilis) or diabetes mellitus
relative afferent pupillary defect from a lesion of an optic nerve and will show what type of pupil?
Marcus Gunn pupil
*common in MS/optic neuritis
how can a relative afferent pupillary defect be tested?
swinging flashlight test
- when light is swung to affected eye, both pupils paradoxically dilate
how will a lesion of an optic tract affect the pupillary light reflex?
slight suppression
how will a lesion in the lateral geniculate nucleus or visual radiations affect the pupillary light reflex?
no change
*will see contralateral homonymous hemianopsia
a lesion to the oculomotor nerve will cause the pupils to…
dilate on the affected side and not constrict to light presented to either eye or to the near response (efferent pupillary defect)
