Case Hx And Refraction Flashcards
US prevalence of strabismus?
2-6%
What is the most common cause of monocular vision impairment in children?
Amblyopia
When should a patient with strabismus NOT have diplopia?
When looking monocularly
What type of anomalies are more likely when strabismus has an earlier onset
Sensory: eccentric fixation, anomalous correspondence, suppression
What is it called when a phoria becomes a strabismus over time?
Decompensated phoria
What is the inheritance pattern of strabismus?
Multifactorial
In Archer’s 1989 study, what age/ developmental stage did infants develop ET?
2-4 months during bifixation development
What is the first step of management for strabismus/ amblyopia?
Refractive status
2 ways to control for accommodation
Distance target; pharmacological (cyclo)
Performing retinoscopy on/off axis is critical to evaluation of refractive status
On-axis
Characteristics of ideal cycloplegic agent?
Rapid onset, complete paralysis, adequate duration, rapid recovery, absence of side effects
Which cycloplegic agent is the standard of care for strabismic and/ or amblyopia patients?
Cyclopentolate
30-40 minute max effect; lasts for several hours
can add tropicamide (faster time of onset plus better dilation) or phenylephrine
What are the signs/ symptoms associated with strabismus?
- excessive blinking/ eye rubbing
- Diplopia
- head turn/ tilt
- closing/ squinting one eye
What are the common complaints associated with strabismus?
- cosmesis
- failed school screening
- signs/ symptoms
- family history
- second opinion
What do we need to know about the diplopia a patient is experiencing?
- Monocular vs binocular
- Distance vs near vs both
- Which gaze(s) does it occur? Any associated activities?
What are the 3 general themes associated with signs and symptoms of strabismus?
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
Dizziness, tingling and weakness with strabismus might indicate what?
Possible ischemic event- refer to neuro
What is a concern when a child has infantile strabismus?
The earlier the onset, the higher the risk that the binocular system did not have time to develop a normal binocular potential
What are some causes of sudden onset strabismus?
trauma, vascular, systemic/ pathologic conditions: neurologic or illness
If retinoscopy is performed off-axis, how will the results compare to the actual refractive error?
Will measure MORE minus
hyperopic: will measure less corrective plus power
myopic: will measure more corrective minus power
What are 2 ways to enable on-axis scoping during dry retinoscopy for a patient with esotropia or hypertropia?
1) use neutralizing prism to align the purkinje images
2) use skiascopy bars
What are the benefits of cycloplegic autorefraction?
can obtain K values and check agreement between subjective and objective testing
What is a good step to take after performing cycloplegic retinoscopy with the skiascopy bars?
Verify with trial frame to reduce amount of possible error
vertex distance, etc
How should ret be performed at a follow up exam?
Dry, over glasses originally prescribed
