Visual pathway Flashcards
what is the definition of a visual field
everything you can see with one eye (including in your periphery)
how do you test visual fields
confrontation test (outpatient screening) or automated perimetry)
NOT the same as visual acuity (snellan chart)
how are images of objects in your visual field originally formed
upside down - inverted on your retina
where do all fibres from the eye originally travel
through the optic nerve to the optic chiasma
what happens at the optic chiasma
the medial nasal fibres cross over to the other side
what fibres does the optic tract contain
fibres from the lateral temporal half of the ipsilateral eye
crossed over medial nasal fibres from the contralateral eye
where do fibres from the optic tract synapse
at the lentiform geniculate body (LGB) of the thalamus
from synapsing on the LGB where does the optic radiation pass
passes behind the internal capsule (retro-lentiform fibres) to reach the primary visual cortex
where is the primary visual cortex located
the occipital lobe
what side of the visual field would the right visual cortex see
the left half of the visual cortex
and vice versa
what damage would you expect from damage to the right optic nerve
whole blindness in the right eye
what damage would you expect from the optic chiasma being disrupted in the middle
bitemporal hemianopia - loss of vision in lateral halves of vision in each eye
what damage would you expect if the right optic tract was damaged
contralateral homonymous hemianopia - loss of vision in left halves of vision in each eye
what damage would you expect if the optic radiation of the right side is damaged
contralateral homonymous hemianopia - loss of vision in left halves of vision in each eye
