8.2.3 Clinical Examination of Eye Movements

Question 1

How do you test muscles that share the same movements?

Answer 1

Change the gaze, some muscles are more dominant in certain positions

Question 2

What type of movement can be used to test eye muscles?

Answer 2

H sign

Lateral movements can be used to make one eye move medially and the other laterally, thus in the adducted eye oblique muscles are more dominant and the abducted eye rectus more dominant

Question 3

What is strabismus?

Answer 3

Ocular misalignment

Common in children (congenital or develops in infancy) cause not always known

Question 4

How does strabismus occur in adults?

Answer 4

Acquired due to pathology involving NMJs e.g. myasthenia gravis or nerves supplying muscles CNIII,IV,VI

Question 5

How can cranial nerves be affected in strabismus?

Answer 5

Vasculopathic, microvascular ischaemia due to diabetes or hypertension
Physical compression, tumour or aneurysm (III)
Raised ICP

Question 6

When is the pupil spared in oculomotor pathology?

Answer 6

Vasculopathic causes, compression can press on the peripheries of CNIII causing pupil blowout as parasympathetics travel on the outside

Question 7

How do paitents with CNIV palsy compensate?

Answer 7

Tilt their head as eye will be pulled upwards and medially, so if head tilted in opposite direction light will hit the retina in the same place

Question 8

When is diplopia worse in a CNIV lesion?

Answer 8

Looking down and medially, e.g. walking downstairs or reading

Question 9

When is diplopia worse in a CNVI lesion?

Answer 9

Horizontal gaze

Question 10

What is the most likely cause of CNIII,IV and VI lesions?

Answer 10

Vasculopathic
Paitents otherwise asymptomatic
Lesions usually self-resolve within a few months

Question 11

What history will suggest other causes?

Answer 11

Headache +/- vomiting could suggest raised ICP (secondary to tumour or haemorrhage)
Recent head injury
Presence of pupil involvement, eye pain/headache