Eye neurology Flashcards
Which part of the brain is the visual cortex in?
Occipital lobe
Describe the pathway of the visual field
Globes Optic nerves Optic chiasm Optic tract Lateral geniculate Cortex
What muscle does CN VI supply?
Lateral rectus
How is lateral rectus tested?
Try to look laterally. Eye will pull medial if LR injured
What causes a CN VI palsy?
Microvascular
Raised ICP
Tumour
What is commonly associated with CN VI palsy?
Bilateral papilloedema
What muscle does CN IV supply?
Superior oblique
How is a CN IV palsy tested?
Eye will look superior since SO causes depression when adducted
Why is there a head tilt present in CN IV palsy?
SO also causes some intorsion so the head has to make up for this
What can also cause bilateral CN IV palsy?
Blunt head trauma since CN IV is at the back of the head so any trauma may cause stretching
How many muscles does CN III supply in the eye region?
6
What is the common presentation for a CN III palsy?
Down and out
Why is a CN III palsy an emergency?
If painful then likely an aneurysm
Also affects levator palpebrae superioris so affects the eyelid
What is strabismus?
Squint
What is inter-nuclear ophthalmoplegia?
The affected eye will not adduct
Unaffected eye will show nystagmus
Where is the injury in inter-nuclear ophthalmoplegia?
Medial Longitudinal Fasiculus, where CN III, IV and VI meet
What is the most common cause of INO?
Multiple Sclerosis
What other, apart from INO, condition is found commonly in MS?
Optic neuritis
What is ION?
ischaemic optic neuropathy
What signs will an optic neuritis present with?
Progressive unilateral visual loss
Colour desaturation
Central scotoma
Pain on moving eye
How is optic neuritis treated?
Steroids
What pathology which affects the optic chiasm can cause visual loss?
Pituitary tumours
If a pathology causes loss of sight of one side of the eye bilaterally, where is the pathology?
Lateral geniculate bodies
or
in occipital cortex
