Eye Movement Defects Flashcards
what is the first manifestation of a squint? (eyes look in different directions)
diplopia
diagnosis of squint
cover test- need a pen torch, occluder and near (1/3m) and distant (6m) targets
should you wear glasses in cover test?
yes
four types of tropias
- esotropia
- exotropia
- hypertropia
- hypotropia
what is esotropia?
outward movement of the eye (convergent)
what is exotropia?
inward movement of the eye (divergent)
what is a hypertropia?
downward movement of the eye
what is hypotropia?
upward movement of the eye
what does ocular motility assess?
muscle pairs
what do you need in an ocular motility assessment?
pen torch
9 positions
should the patient wear their glasses in an ocular motility test?
no
result in ocular motility test if weakness in muscle/muscle pairs
some sclera still seen
three examples of eye movement defects
- VI nerve palsy
- IV nerve palsy
- III nerve palsy
what causes VI nerve palsy?
LR cannot abduct fully
presentation of VI nerve palsy?
some sclera still visible when looking outwards
horizontal diplopia
causes of VI nerve palsy?
raised ICP
tumour
congenital
how does raised pressure affect the CNVI?
nerve rests on temporal bone therefore can be compressed
what is IV nerve palsy?
SO cannot depress the eye
presentation of IV nerve palsy?
eye drifts when looking ahead intorsion depression in adduction weak abduction hypertropia diplopia is vertical head tilt
causes of IV nerve palsy?
congenital decompensated
microvascular
tumour
bilateral in closed head trauma (shaking brain in cranial cavity can stretch the 4th nerve which is very thin)
what is III nerve palsy?
MR, IR, SR, IO, sphincter pupillae and levator palpebrae superioris are affected
presentation of III nerve palsy?
down and out dilated divergent strabismus ptosis diplopia that is horizontal and vertical exotropia with hypotropia
causes of III nerve palsy?
expanding aneurysm (EMERGENCY)
tumour
MS
congenital
what is inter-nuclear ophthalmoplegia?
eyes work together due to connection between the nuclei of the medial longitudinal fasciculus and this is damaged
causes of inter-nuclear ophthalmoplegia?
MS (demyelination)
vascular
mass
presentation of inter-nuclear ophthalmoplegia?
failure to adduct
