Neuro-ophthalmology Flashcards
What causes optic neuritis?
Demyelination of optic nn
- Usually 2’ to MS or ischaemic optic neuropathy (blood clot)
Sx optic neuritis (2)
Blurred vision
Retrobulbar pain on movement
O/E optic neuritis (3)
Red colour vision
RAPD
Central scotoma
If a patient has a repeat episode of optic neuritis, what should be done?
MRI (b/c risk MS)
What is papilloedema
Swelling of optic disc due to incr ICP
Is papilloedema usually uni or bilateral ?
Bilateral
Sx papilloedema (3)
Transient visual obscurations + enlarged blind spots
Gradually progressive
O/E (6)
May have - splint haemorrhages, exudates, cotton wool spots, retinal folds
Enlarged blinds spots
Progressive field loss
What is AAION
Inflammation of the aa to the optic discs which causes infarction
Sx AAION (5)
Temporal headache + Jaw claudication W loss Myalgia Visual loss
O/E AAION (4)
Raised CRP/ESR
Margins blurred
Cup obliterated
Rest of fundus = pallor
Which aa is specifically affected in AAION
Posterior ciliary aa
Mx AAION (2)
Urgent high dose steroids
Continue for 2 years
Temporal aa biopsy within 1 week starting Tx
Which aa is affected in Non-arteritic AION
Posterior communicating aa
O/E NAION (3)
ESR not raised
Swelling not as gross as AAION, visual impairment not as excessive
No systemic Sx
What do 50% of patients with NAION have?
HTN
Tx NAION
Low dose aspirin
Features of optic atrophy (3)
Afferent pupillary defect
Optic nn - atrophic + palsies
Loss surface capillaries
Which mm are affected in CN III palsy? (5)
MR IF SR LPS IO
Appearance eyes IIICN palsy (3)
Eyes point down + out
Ptosis
Dilated/mydriasis
Which mm is affected in CN IV palsy?
SO
Appearance eyes CN IV palsy
Eyes can’t look down + in
What may a patient with CN IV palsy complain of when looking down + in?
Vertical diplopia
What is bilateral CN IV palsy associated with?
Head injuries
What mm is affected in CN VI palsy?
LR
Appearance CN VI palsy
Pt can’t abduct
Eye may drift medially b/c pull medial rectus
What 2 things should you test to see if a patient has CN VII palsy?
Corneal sensation
Bells
What part of the visual circuit is affected if patient presents with bitemporal hemianopia
Optic chiasm
Causes of bitemporal hemianopia (3)
Pit tumour
Meningioma
Aneurysm of ant communicating aa
What part of the visual circuit is affected if patient presents with homonymous hemianopia
Optic tract lesion
Cause of homonymous hemianopia
Usually CVA
Which loop is affected in L superior quandrantopia
Meyers
What cortex of brain is affected in L superior quadrantopia
Temporal lobe
What loop is affected in L inferior quadrantopia
Baum’s
What cortex of brain is affected in L inferior quadrantopia
Parietal
What part of brain is affected if you get homonymous hemianopia w/ macular sparing ?
Visual cortex CVA
Why do you get macular sparing?
B/c macular fibres recieve a sep blood supply to peripheral visual cortex
What is an afferent pupil defect?
Disruption of fibres travelling from RCG to PTN and from PTN to same + contralateral EWN
Affect of Afferent pupil defect on pupillary responses
No consensual or direct response
Affect of RAPD on pupillary responses
Reduce light + consensual response
Pupil dilates on swinging light test
What causes Horner’s syndrome?
Lesion of sympathetic pathway
PS Horner’s syndrome
Affected pupil smaller than usual
Apparent enophthalmos
Partial ptosis
Cause fo Argyll Robertson Pupils
Congenital syphillis
Appearance + response of Argyll Robertson Pupils (4)
Pupils small + irreg
Sluggish light responses
Light near dissociation
Sometimes blind
Appearance + response Argyll Robertson Pupils (3)
Efferent defect
SLugish pupil response
LND
