optic disc and visual fields Flashcards
which cranial nerve is the optic nerve?
CNII
Is the optic nerve an afferent or an efferent nerve?
afferent (sensory)
-takes info from eye to the brain
what different types of vision can we test in the optic nerve?
- direct response (pupils)
- RAPD
- peripheral
- central
- visual fields
why is the cup in optic nerve important?
- if you can see a cup the nerve is not swollen
- how much tissue you have in longitudinally
what would cause the nerve to go pale?
- demyelination
- ischaemia
what are you looking for when looking at an image of an optic nerve?
- contour
- colour
- cup
what does expansion of the cup mean?
-you’ve lost tissue
how may the optic nerve present in glaucoma?
- asymmetry of optic nerve
- enlarged cup
what is this?
-swollen disc
what can cause swelling of the disc?
- people with raised ICP
- vascular ischaemia
- sometimes putting in dilating fluid
how does a swollen disc present?
- indistinct contour
- colour varies, depends how long it’s been swollen for (may have haemorrhages or be pale)
what should you rule out of you see a bilateral swollen disc (nerve)?
-raised ICP
what is a disc drusen?
-usually lumps of calcium in the optic nerve
how may disc drusen present?
- assymetry of optic disc
- swollen optic disc
