Neuro-opthalmology Flashcards
What signals a neuro problem in eye exam?
optic nerve dysfunction ie. problem with VA, colour vision and pupil
ocular motility dysfunction
How does optic neuritis present?
variable loss of vision
washed out colours
dull ache on eye movement
What are signs of optic neuritis picked up on exam?
dec VA and colour vision
RAPD
enlarged blind spot
swollen optic disc
Is optic neuritis unilateral or bilateral?
unilateral
What is the most common cause of optic neuritis?
demyelination
What causes bilateral swollen discs?
papilloedema due to raised ICP
What retina is responsible for the temporal field of vision?
nasal retina
What retina is responsible for the nasal field of vision?
temporal retina
The optic nerve arising from which retina crosses at the optic chiasm?
nasal retina ie. temporal field of vision
What visual field defect does a lesion of the optic nerve cause?
unilateral visual loss
What can cause an optic nerve lesion?
pituitary tumour
What visual field defect does a lesion of the optic chiasm cause?
bitemporal hemianopia (ie loss of temporal vision in both eyes)
What visual field defect does a lesion of the optic tract cause?
homonymous hemianopia
- if on the left lose left nasal vision, and right temporal vision
- if on the right lose right nasal vision and left temporal
What visual field defect does a lesion of the cortex cause?
cortical blindess ie. homonymous hemianopia with macular sparing
What is a direct pupil response?
if you shine a light on a pupil it constricts
What is a consensual pupil response?
if you shine a light on a pupil the other constricts
What is a RAPD?
when you shine a light on one pupil, the other has a paradoxical dilation because of optic nerve dysfunction in that eye
What causes horner’s syndrome?
paralysis of the sympathetic supply somewhere along the chain
What are specific causes of horner’s?
pancoast tumour
carotid/aortic aneurysm
neck lesions
congenital
How does horner’s syndrome present?
ptosis (droopy eyelid)
miosis (constricted pupil)
anhidrosis (reduced ipsilateral sweating)
How do lesions of CN III, IV and VI affect vision?
cause diplopia
What differentiates true diplopia from an ocular problem?
in true diplopia covering an eye will not resolve the problem whereas in an ocular problem it will
What commonly causes CN palsies?
microvascular
How does a CN III palsy present? why?
down and out eye position –> MR, IR, SR, IO
ptosis –> levator palpibrae
unreactive, dilated pupil –> sphincter pupillae
What causes oculomotor palsy?
microvascular
trauma
PCA aneurysm
How does a CN IV palsy present?
weakness of superior oblique
hyperdeviated eye (points up)
excylotorsion (rotates out)
cant depress eye in adduction
How does a CN VI palsy present?
lateral rectus weakness
weak abduction and horizontal double vision
What causes a CN VI palsy?
microvascular
acoustic neuroma
raised ICP
basal skull #
