Case Hx And Refraction

Question 1

US prevalence of strabismus?

Answer 1

2-6%

Question 2

What is the most common cause of monocular vision impairment in children?

Answer 2

Amblyopia

Question 3

When should a patient with strabismus NOT have diplopia?

Answer 3

When looking monocularly

Question 4

What type of anomalies are more likely when strabismus has an earlier onset

Answer 4

Sensory: eccentric fixation, anomalous correspondence, suppression

Question 5

What is it called when a phoria becomes a strabismus over time?

Answer 5

Decompensated phoria

Question 6

What is the inheritance pattern of strabismus?

Answer 6

Multifactorial

Question 7

In Archer’s 1989 study, what age/ developmental stage did infants develop ET?

Answer 7

2-4 months during bifixation development

Question 8

What is the first step of management for strabismus/ amblyopia?

Answer 8

Refractive status

Question 9

2 ways to control for accommodation

Answer 9

Distance target; pharmacological (cyclo)

Question 10

Performing retinoscopy on/off axis is critical to evaluation of refractive status

Answer 10

On-axis

Question 11

Characteristics of ideal cycloplegic agent?

Answer 11

Rapid onset, complete paralysis, adequate duration, rapid recovery, absence of side effects

Question 12

Which cycloplegic agent is the standard of care for strabismic and/ or amblyopia patients?

Answer 12

Cyclopentolate

30-40 minute max effect; lasts for several hours

can add tropicamide (faster time of onset plus better dilation) or phenylephrine

Question 13

What are the signs/ symptoms associated with strabismus?

Answer 13

• excessive blinking/ eye rubbing
• Diplopia
• head turn/ tilt
• closing/ squinting one eye

Question 14

What are the common complaints associated with strabismus?

Answer 14

• cosmesis
• failed school screening
• signs/ symptoms
• family history
• second opinion

Question 15

What do we need to know about the diplopia a patient is experiencing?

Answer 15

1. Monocular vs binocular
2. Distance vs near vs both
3. Which gaze(s) does it occur? Any associated activities?

Question 16

What are the 3 general themes associated with signs and symptoms of strabismus?

Answer 16

1) discovery or change in frequency or magnitude (over course of day OR since initial discover)
2) no apparent strab, but experiences signs/ symptoms; possible diplopia
3) discovery of poor VA

Question 17

Dizziness, tingling and weakness with strabismus might indicate what?

Answer 17

Possible ischemic event- refer to neuro

Question 18

What is a concern when a child has infantile strabismus?

Answer 18

The earlier the onset, the higher the risk that the binocular system did not have time to develop a normal binocular potential

Question 19

What are some causes of sudden onset strabismus?

Answer 19

trauma, vascular, systemic/ pathologic conditions: neurologic or illness

Question 20

If retinoscopy is performed off-axis, how will the results compare to the actual refractive error?

Answer 20

Will measure MORE minus

hyperopic: will measure less corrective plus power

myopic: will measure more corrective minus power

Question 21

What are 2 ways to enable on-axis scoping during dry retinoscopy for a patient with esotropia or hypertropia?

Answer 21

1) use neutralizing prism to align the purkinje images
2) use skiascopy bars

Question 22

What are the benefits of cycloplegic autorefraction?

Answer 22

can obtain K values and check agreement between subjective and objective testing

Question 23

What is a good step to take after performing cycloplegic retinoscopy with the skiascopy bars?

Answer 23

Verify with trial frame to reduce amount of possible error

vertex distance, etc

Question 24

How should ret be performed at a follow up exam?

Answer 24

Dry, over glasses originally prescribed