visual field and lesions

Question 1

visual field

Answer 1

what is viewed by the eyes

Question 2

how can the retina be divided?

Answer 2

-into nasal and temporal half
-into superior and inferior half

Question 3

how does vision come in from the field to the hemiretinas?

Answer 3

crosses over
-ex. from temporal visual field project to the nasal hemiretina

Question 4

ipsilateral blindness

Answer 4

lesions on one optic tract coming from one eye
-occurs before crossing over
-complete lesions on both visual fields from one eye

Question 5

bi-temporal heteronymous hemianopsia (tunnel vision)

Answer 5

lost the crossing fibers
-compression on the optic chiasms
-blindness in the nasal hald of retina or temporal half of the visual field of each eye

Question 6

ipsilateral nasal hemianopsia

Answer 6

compressing/pushing on nerve fibers
-affects only a portion of one eye
-one eye is losing the nasal visual field

Question 7

contralateral homonymous hemianopsia

Answer 7

an entire visual field, right or left, from both eyes
-seeing everything on one side and nothing on the other side
only seeing the left or right visual field and not the whole picture

Question 8

contralateral lower quadrantic anopsia

Answer 8

taking out a quadrant of an eyes visual field
-only one of the fibers coming from this eye in the back of the brain area has been affected

Question 9

cortical blindness

Answer 9

light reflexes may be intact but the visual information never reaches the primary visual cortex

Question 10

macular sparing

Answer 10

there may still be blood supply to the foveal or macular regions by the middle cerebral artery, even if the calcarine artery is occluded