Neurology/Neurosurgery - Diplopia

Question 1

What is the difference between monocular and binocular diplopia?

Answer 1

Binocular disappears when you cover one eye

Monocular does not.

Question 2

Where is the likely cause of monocular diplopia?

Answer 2

Usually, it will be a problem with the eye itself and not with convergence

Question 3

What is usually the cause of binocular diplopia?

Answer 3

Usually, it will be a problem with convergence of the left and right eye and a misalignment.

Question 4

What are the reasons your eyes might not converge?

Answer 4

Eyes move due to muscles, under control of the nerves.

Therefore problem may be due to muscle problems or may be due to nerve problems

Question 5

What muscle(s) are controlled by the abducens nerve?

Answer 5

LR6 - lateral rectus - abducts eye

Question 6

What muscle(s) are controlled by the trochlear nerve?

Answer 6

SO4 - Superior oblique. Abducts, depresses and internally rotates the eye - (?change this based on rachel’s answer!)

Question 7

What muscle(s) are controlled by the oculomotor nerve?

Answer 7

AO3 - all others 3.

• medial rectus - adducts eye
• inferior rectus - depresses eye
• superior rectus - elevates eye
• inferior oblique - abducts, elevates and externally rotates eye
• levator palpaebrae superioris - elevates eyelid
• Sphincter pupillae - constricts pupil (parasympathetic innervation)

Question 8

What would be seen in an abducens palsy then?

Answer 8

Failure to abduct the affected eye. Diplopia maximum in lateral gaze on affected side. Causes an esotropia.

Question 9

Which nerve(s) are most susceptible to a raised ICP?

Answer 9

Abducens - 6th nerve palsy may be an early sign of raised ICP/idiopathic intracranial hypertension.