S5 - Retina and Visual Pathways

Question 1

Lec 5 - do the cover test on anatomy on the first slide

Answer 1

do it

Question 2

what is papilodema - what is seen?

Answer 2

loss of healthy optic disc due to raised ICP

Question 3

what is the macula and the fovea

Answer 3

central point with most dense rods and cones for colour vision

fovea is a dip in the surface

Question 4

draw out the nerve route of CNII all the way to PVC

then add Visual feilds, and what are they responible for?

Answer 4

temporal fibers responsible for nasal visual fields

nasal fibers are responsible for temporal visual fields

Question 5

outline what is seen in a lesion too

cnII
optic chiasm ( plus two reasons why)
Optic tract

what is the pattern of visiaul field loss, whats is the name of this ?

use drawing from previous Q to help

Answer 5

monocular blindness

bitemporal heminopia

homonous heminopia (R or L)

Question 6

optic radiations - are responisble for which quadtrant

Answer 6

sup rad - inferior quadrant of vision

inf rad - superior quadrant of vision

Question 7

outline what is seen in a lesion too

superior optic radiation in parietal lobe

inferior optic radiation in temporal lobe

both inf and sup radiatons same side are affected eg in a stroke

what is the pattern of visiaul field loss, whats is the name of this ?

use drawing from previous Q to help

Answer 7

check vs lecture
quadrinopias

aka move diagonally always

Question 8

outline what macula sparing is

Answer 8

occipital lobe has a dual blood supply - PCA and MCA

a PCA stroke - MCA and hence supply to macula is spared

but most of occiptial lobe and rest of vision is lost

tunnel vision

Question 9

outline the accommodation reflex

KEY

Answer 9

taught mainly in groupwork, so check that and youtube videos

• Required for near vision
• 3 aspects (3 ‘C’s):
• Convergence (medial rectus)
• Pupillary Constriction (constrictor pupillae)
• Convexity of the lens to increase refractive power (ciliary muscle)
• Cerebral cortex must be involved because it is relating to image
analysis
• Therefore the reflex follows the visual pathway via the lateral
geniculate nucleus to the visual cortex

from PVC to CNIII and EWN triggering bilateral synchrinised action - Watch youtube video !!

this has links to demylination conditions such as multiple sclerosis

Question 10

what si amurosis fugax

Answer 10

transient blindness due to hypoxia from occlusion of the central retinal artery