Diplopia Flashcards
4 classes of dip.
- physiological - object outside point of fixation
- monocular - eye or glasses abnormality
- binocular - ocular misalgnment
- cerebral polyopia - processing problem - persists with a pinhole
how to diff. between monocular and binocular dip.
if persists with one ey closed, it is monocular
what is cause of binocular dip.
ocular misalignment
causes of mono. dip (7)
- astigmatism
- lid lesion
- dry eye
- corneal damage
- iridotomy
- cataracts
- decentered lens
what happens in mono with pinhole
resolves
2 causes of ocular misalignment
- innervational
2. mechanical
6 clues to cause of binoc. dip.
- image sep.
- head posture
- ptosis
- comtancy
- light reflex
- alternate cover test
what does image separation tell us
max. separation in position of gaze where muscle is weakest
what does head position tell us
in 4th nerve palsy the head tilts to the opposite shoulder
4 mimickers of true ptosis
- hypotropia
- contralateral lid retraction (graves)
- dermatochalsis
- brow ptosis
what are names of eyes pointing in various directions
up: hypertrophia
down: hypotrophia
in: esotrophia
out: exotrophia
what is most common cause of ptosis
involutional, not neurogenic
what happens in alternate cover test
when cover the good eye, the bad one comes to look at you
what is comitant eye gaze
symmetric misalignment in all positions of gaze
what does comitant vs. incomitant tell us
- comitant - childhood strabismus or chronic innervational disease
- incomitant - innervational or mechanical
sign of CN 6 palsy and type of dip
eye inward - horizontal
sign of CN4 palsy
affected eye higher - tilts head to opposite side of lesion
3 step test for CN4 palsy
- when look ahead the higher eye has palsy
- on lat. gaze, the object sep. increases in direction opp. of palsy
- on head tilt the sep. increases when tilt head towards the palsy
signs of CN3 palsy
down and out and may or may not have blown pupil
causes of CN3
aneuysm if pupil
ischemia, trauma
what is worse sign, complete or partial sparing
partial sparing
what is internuclear opthalmoplegia
lesion of the MLF causes ipsilateral loss of abbduction to side of lesion
what happens in pituitary apoplexy
CN3 palsy and bitemporal hemianopsia
2 conditions least likely to have loss of acuity and binocular diplopia
- CN3 palsy
2. myasthenia gravis
treatment for monocular
glasses, tears, catarct surgery
treatment for binocla
prism glasses, patch, surgery
2 options in surgery
- weaken agonist muscle
2. stengthend antag.
when to do surgery
after some time and have tried other options
what must be done if dip doesnt decrease after 3-6 months
image
what is dangerous dip.
misalignment + eyelid, pupil, optic nerve abnormality
