W6_10 Approach to Diplopia Flashcards
what’s cerebral polyopia?
an uncommon disorder that has a homonymous visual field defect due to some cerebral lesion
how can you decrease monocular diplopia acutely (non-medical)?
using a pinhole
if diplopia is worse in left gaze, which cranial nerve is likely affected?
left CN VI
a head tilt could indicate a palsy of which cranial nerve?
CN IV of opposite side of tilt of tilt
hypotropia, contralateral lid retraction, dermatochalasis, brow ptosis are all what?
pseudoptosis
three types of true ptosis?
neurogenic (e.g. CN III, horners);
myogenic;
mechanical
the alternate cover test is used for testing what?
binocular diplopia
what can cause comitant bip. diplopia?
childhood strabismus or chronic innervational disease
what can cause incomitant bip diplopia?
innervational (eg. CN III palsy); mechanical disease (eg. Graves disease)
what should you r/o when you see CN VI palsy? why?
r/o increased ICP, so check for papilledema; recall CN VI has to climb the clivus and has to bend, so it’s susceptible to pressure
if patient tilts head to the left, what CN palsy does that indicate?
right CN IV palsy (contralateral to the tilting)
what’s the 3 step test for CN IV palsy?
1: hypertropia of affected eye
2: lateral gaze to opposite side increases diplopia
3: head tilt to same side of palsy increases diplopia
you see signs of CN III lesions, and see that pupil is affected. what are you worried about?
aneurysm (along the circle of willis arteries, esp PComm)
you see signs of CN III lesions, and see that pupil is not affected. what is likely cause?
microvascular ischemic
what is amblyopia?
impaired or dim vision of a greater degree than it looks