10 - Opth - Squints - Incomitant Squints

Question 1

usually due to? can be due to?

Answer 1

CN palsies
occasionally myopathies (usualy bilateral)

Question 2

What would eye with a CNIII palsy look like + why?

Answer 2

only LR and SO spared, therefore,
eye looks down and out

complete ptosis (levator paralysis)

efferent pupillary defect (fixed dilated pupil)

Question 3

What would eye with a CNIV palsy look like and why?

Answer 3

SO affected
eye looks upwards at rest/adduction

pt may complain of tilted image

unable to look down and in (diplopia on looking down)

Question 4

what would eye with a CNVI palsy look like and why?

Answer 4

LR affected
unable to abduct affected eye
eye may drift medially (esotropia)

Question 5

5 causes of neurogenic palsies - think surgical sieve

Answer 5

vascular - eg microvascular - likely cause if pupil sparing CNIII lesion
trauma - head injury
tumour - esp suspect in kids
inflammatory - eg post viral
infection - middle ear with VI palsy, HZoster Opthalmicus

Question 6

Mechanical causes of incomitant squint

Answer 6

blow out fractures

thyroid eye disease

Question 7

Myogenic causes of incomitant squint

Answer 7

Myasthenia Gravis

Tumour/inflammation of EOMuscles

Question 8

Mgmt of diplopia in incomitant squints

Answer 8

Prisms on glasses (combo images)
Occlusion (patch - temp/perm solution)
Surgery - if stable diplopia, aim to treat for primary (ahead) and depressed (reading) vision