BVP - Strabismus Assessment II - Week 11 Flashcards Preview

OD2 - Applied Clinical Training & Research Studies in Vision and Optometry > BVP - Strabismus Assessment II - Week 11 > Flashcards

Flashcards in BVP - Strabismus Assessment II - Week 11 Deck (21)
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1
Q

How can the comitancy of strabismus be checked?

A

Observe the magnitude of the strabismus in all 9 gazes using a pentorch (hirschberg) or cover test

2
Q

What is meant by a comitant strabismus?

A

It has the same magnitude in all 9 directions of gaze

3
Q

What is meant by a incomitant strabismus?

A

Varies by 10^D or more in different positions of gaze

4
Q

Describe what incomitancy would be seen with a 4th nerve palsy (what strabismus and in what gaze).

A

Vertical incomitance in R-L gaze

5
Q

Describe what incomitancy would be seen with a 6th nerve palsy (what strabismus and in what gaze).

A

Horizontal incomitance in R-L gaze.

6
Q

Describe what incomitancy would be seen with musclew malinsertion (what strabismus and in what gaze).

A

Horizontal incomitance in up-down gaze

7
Q

Describe what incomitancy would be seen with a high AC/A ratio (what strabismus and in what gaze).

A

Horizontal incomitance in near-far fixation

8
Q

List three common causes of incomitancies.

A

A and V pattern in esotropia and exotropia
4th nerve palsy
Duane’s syndrome

9
Q

What is the cause of duane’s syndrome?

A

Congenital 6th nerve palsy

10
Q

What is the cause of 4th nerve palsy (2)?

A

Can be congenital but also trauma

11
Q

What does A and V pattern in esotropia and exotropia indicate and what prognosis (good or poor)?

A

Indicates early onset strabismus with poor prognosis

12
Q

List 3 uncommon causes of incomitancies. Note if it is acquired or congenital.

A

Browns syndrome
Acquired 6th nerve palsy
Congenital 3rd nerve palsy

13
Q

What is browns syndrome and what happens with time?

A

Problem relaxing the superior oblique through the trochlea that often improves with age

14
Q

Consider a monocular H test (action field). List the muscles used to bring the eye to each fixation (one each) for all 6 positions.

A
IO         SR
  I            I
MR ----- LR
  I            I
SO         IR
15
Q

Describe the parks three steps test (3).

A

Note which eye is higher (hypertropic) in the primary gaze
Note if the hypertropia is worst in the left or right gaze
Note if the hypertropia is worst if the head is tilted left or right, using the midline of the head to note affected muscles
In each case, using a monocular H action field circle the affected muscles
By the end of the test, the muscle circles most (three times) is the affected muscle
-note which eye and muscle

16
Q

List the three golden rules of pratt johnson.

A

The strabismus is a superior oblique palsy until proven otherwise
Congenital until proven otherwise
Patients usually dont fixate with the eye that has a palsy

17
Q

What is the deviation of esotropia like at near vs distance typically?

A

Often the same

18
Q

Describe what convergence excess esotropia is, its cause, and what it responds to.

A

When near deviation of esotropia is worse than distance
Almost always caused by a high AC/A ratio
Responds to plus addition (bifocals)

19
Q

What is it called when distance deviation of esotropia is worse than near deviation?

A

Divergence insufficiency

20
Q

What is divergence deficiency usually caused by?

A

6th nerve palsy, which innervates the lateral rectus - abduction deficit

21
Q

What is 6th nerve palsy typically caused by (pathology)? What should be done in these cases?

A

Intracranial pathology that increases pressure inside the brain (hydrocephalus or tumour)

Urgent referral to an ophthalmologist needed, may have papilloedema

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