Neuro-opthalmology

Question 1

What signals a neuro problem in eye exam?

Answer 1

optic nerve dysfunction ie. problem with VA, colour vision and pupil

ocular motility dysfunction

Question 2

How does optic neuritis present?

Answer 2

variable loss of vision
washed out colours
dull ache on eye movement

Question 3

What are signs of optic neuritis picked up on exam?

Answer 3

dec VA and colour vision
RAPD
enlarged blind spot
swollen optic disc

Question 4

Is optic neuritis unilateral or bilateral?

Answer 4

unilateral

Question 5

What is the most common cause of optic neuritis?

Answer 5

demyelination

Question 6

What causes bilateral swollen discs?

Answer 6

papilloedema due to raised ICP

Question 7

What retina is responsible for the temporal field of vision?

Answer 7

nasal retina

Question 8

What retina is responsible for the nasal field of vision?

Answer 8

temporal retina

Question 9

The optic nerve arising from which retina crosses at the optic chiasm?

Answer 9

nasal retina ie. temporal field of vision

Question 10

What visual field defect does a lesion of the optic nerve cause?

Answer 10

unilateral visual loss

Question 11

What can cause an optic nerve lesion?

Answer 11

pituitary tumour

Question 12

What visual field defect does a lesion of the optic chiasm cause?

Answer 12

bitemporal hemianopia (ie loss of temporal vision in both eyes)

Question 13

What visual field defect does a lesion of the optic tract cause?

Answer 13

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

Question 14

What visual field defect does a lesion of the cortex cause?

Answer 14

cortical blindess ie. homonymous hemianopia with macular sparing

Question 15

What is a direct pupil response?

Answer 15

if you shine a light on a pupil it constricts

Question 16

What is a consensual pupil response?

Answer 16

if you shine a light on a pupil the other constricts

Question 17

What is a RAPD?

Answer 17

when you shine a light on one pupil, the other has a paradoxical dilation because of optic nerve dysfunction in that eye

Question 18

What causes horner’s syndrome?

Answer 18

paralysis of the sympathetic supply somewhere along the chain

Question 19

What are specific causes of horner’s?

Answer 19

pancoast tumour
carotid/aortic aneurysm
neck lesions
congenital

Question 20

How does horner’s syndrome present?

Answer 20

ptosis (droopy eyelid)
miosis (constricted pupil)
anhidrosis (reduced ipsilateral sweating)

Question 21

How do lesions of CN III, IV and VI affect vision?

Answer 21

cause diplopia

Question 22

What differentiates true diplopia from an ocular problem?

Answer 22

in true diplopia covering an eye will not resolve the problem whereas in an ocular problem it will

Question 23

What commonly causes CN palsies?

Answer 23

microvascular

Question 24

How does a CN III palsy present? why?

Answer 24

down and out eye position –> MR, IR, SR, IO
ptosis –> levator palpibrae
unreactive, dilated pupil –> sphincter pupillae

Question 25

What causes oculomotor palsy?

Answer 25

microvascular
trauma
PCA aneurysm

Question 26

How does a CN IV palsy present?

Answer 26

weakness of superior oblique
hyperdeviated eye (points up)
excylotorsion (rotates out)
cant depress eye in adduction

Question 27

How does a CN VI palsy present?

Answer 27

lateral rectus weakness

weak abduction and horizontal double vision

Question 28

What causes a CN VI palsy?

Answer 28

microvascular
acoustic neuroma
raised ICP
basal skull #