Ocular-motor Disorders

Question 1

Phoria

Answer 1

Indicates weakness of a muscle

If eye is not focused on something, it drifts.

Question 2

Tropia

Answer 2

Indicates paralysis of the muscle.

Eye drifts even when focusing on a target

Question 3

Eso

Answer 3

Eye is deviated inward

Esophoria, esotropia

Question 4

Exo

Answer 4

Eye is deviated outward

Exophoria, exotropia

Question 5

Hyper

Answer 5

Eye is deviated upward

Hyperphoria, hypertropia

Question 6

Hypo

Answer 6

Eye is deviated downward

Hypophoria, Hypotropia

Question 7

Which CN constricts the pupil? Sympathetic or parasympathetic?

Answer 7

Parasympathetic fibers of CN III. They supply the ciliary body and sphincter of iris.

Question 8

Acquired CN III palsy

Answer 8

• Sudden onset of binocular horizontal, vertical or oblique diploplia.
• Ptosis or droopy eyelid.

Question 9

Congenital CN III Palsy

Answer 9

• Found in young children
• May be able to suppress the second image in diploplia, may not complain.
• Ptosis and strabismus
• Amblyopia is major complication

Question 10

Complete CN III palsy is usually associated with a large angle _____ and _____?

Answer 10

Exotropia and hypotropia. Down and out.

Question 11

CN III palsy differential

Answer 11

• HTN, diabetes
• Tumor
• Congenital
• Aneurism

Question 12

CN III Palsy Tx

Answer 12

• Neuroimaging
• Consult a neuroradiologist
• Tx is directed at underlying etiology
• Maximize function

Question 13

CN IV

Answer 13

Trochlear nerve
Has longest intracranial course
Only nerve with a dorsal exit from the brainstem
Innervates Superior Oblique (SO4)

Question 14

CN IV Palsy

Answer 14

• Binocular vertical diploplia/subjective tilting of objects

- Neck pain

Question 15

What is nasal upshoot?

Answer 15

Ipsilateral Hypertropia. Eye is deviated upward .

Question 16

CN IV Palsy causes greater hypertropia in _____ gaze.

Answer 16

Left

Question 17

CN IV Palsy Tx

Answer 17

Neuroimaging
LP if negative imaging
Treat underlying etiology

Question 18

CN VI

Answer 18

Abducens Nerve
Enters orbit via the superior orbital fissure
Innervates Lateral rectus (LR6)

Question 19

CN VI Palsy

Answer 19

• Binocular horizontal diploplia that worsens with gaze toward defective lateral rectus muscle.
• Strabismus toward paralyzed side.

Question 20

CN VI Palsy Presentation

Answer 20

• Primary position esotropia

- Eye is turned in (crossed eye)

Question 21

When is CN VI palsy an emergency?

Answer 21

When focal signs or papilledema are present

-Increased ICP