BVP - Treatment of Amblyopia - Week 3 Flashcards
How is occlusion for amblyopia treatment done, what does it force, and what does it inhibit?
Occluding the dominant eye
-forces the non-dominant eye to take up fixation
-reduces the dominant eye’s inhibition of amblyopic eye
List four types of occluders. Note which is not recommended and which is used in special cases.
3M opticlude patches
Material ‘over the spectacle’ patches
Opaque material stuck to spectacle lens - not recommended
Black contact lenses - special cases
What does full time occlusion entail? Does prescribing less than this achieve adequate results?
Child is required to wear the patch all waking hours, generally 6-7 days
Many practitioners prescribe less than this and appear to achieve adequate results
Is full time occlusion the mainstream approach?
Until very recently
How long does full time occlusion take to get a good response and how long will it take to get the majority of the effect? Explain the full effect.
Generally get a good response in 3 months
Will need 6 months to get the majority of the effect
If for another year or two, may improve another line or two
Is improvement in acuity with amblyopia treatment symptomatic or asymptomatic?
Asymptomatic
Do children as old as 12 respond as well as younger children to amblyopia treatment? Explain (3).
Yes but:
-response not as good
-response is slower
-compliance is poorer
How effective is full time occlusion in reaching the following goals in cumulative total percentage?
6/6
6/9 or better
6/12 or better
6/6 - 53%
6/9+ - 73%
6/12 - 87%
What is the compliance thought to be for full time occlusion?
~50%
Is compliance better or worse in lower socioeconomic groups?
Worse
Is compliance higher or lower in private practice?
Higher, allegedly
List four tips to improve occlusion compliance.
Parents need to be aware their child will not like it and be prepared
Child needs to be aware that occlusion is non-negotiable
Parents need to fill out an occlusion calendar so you know they are doing it
Child needs to be provided with some rewards for complying
Explain why full time occlusion was the mainstay treatment until only recently and explain what the ATS2B study proved. Make a comparison for the end result and rate of improvement, and the severity of amblyopia it applies to.
Minimal occlusion works perfectly
Major finding in ATS2B was that 2h occlusion worked as well as 6h occlusion for moderate amblyopia over 4 months
-same end result
-same rate of improvement
Consider minimal patching (2h per day). If stable visiond is achieved after 3 months, what effect does switching to 6h occlusion per day (full time) have on VA?
It improves further
Define recidivism. When is it more (2) and less likely (1)?
Some amblyopes get worse once treatment stops
Less likely if the cause of the amblyopia is treated
More likely if it is untreated
-residual strabismus
More likely if the child is younger
Up to what age can recidivism occur?
Up to age 11
What is the incidence of recidivism after treatment is ceased (percentage)?
Up to 24%
What can be a way to detect recidivism? Give a guideline.
Review after a month after treatment stopped
Guideline schdeule:
1 month, 3 months, 6 months, then yearly
What is meant by maintenance therapy for recidivism?
If they have optical penalisation for a year or more, then anecdotally no recidivism
What is failure of amblyopia treatment defined as?
Less than 6/12 acuity
In what percentage of children will amblyopia treatment fail in private practice? Break them down into causes (3) and what should be done in these cases if applicable.
Will fail 15% of the time
10% from compliance failures
-advise on compliance
4% for unknown reasons
-second opintion from ophthalmology
1% will be eccentric fixation
-no treatment effective
Describe what penalisation for amblyopia does, what it removes, and whether it affects distance or near.
Reduces the resolution of the input of the dominant eye, rather than totally block it out
Removes high frequency high acuity data
This can be done at distance, near, or both
Can penalisation be done with dense amblyopia?
No, it will not work
What does penalisation require of the non-dominant eye?
‘adequate’ vision
Describe the left/right hand analogy to how penalisation may work.
How great an injury do you need to your right hand to use your left instead?
How much do you need to blur the dominant eye for them to swap fixation with an amblyopic eye of 6/18 acuity?
3 or more lines of blur
How can you tell if an amblyopic patient has swapped fixation?
Measure binocular acuity, then each eye
-if the eyes are still straight
List three types of penalisation.
Fogging
Atropine
Bangerter/Cling foils
Describe how fogging penalisation is done. What acuity level does it generally need and why?
+1.00D to +3.00D is added to the dominant eye
Generally requires at least 6/12 acuity for adequate compliance (ie peeking over the spectacles)
When doing fogging penalisation, which eye will fixate at near?
The dominant eye
What is the compliance of fogging penalisation like?
97%
Describe atropine penalisation.
Amblyopia treatment primarily by blurring dominant eye at near
Can atropine penalisation be used on most amblyopes?
Yesd
In what demographic of patients is atropine penalisation most useful?
In children younger than 2.5 years of age who wont wear a patch
Does atropine sting?
No
What does an emmetrope blur to at near with atorpine? What about if they are hyperopic (including latent)?
6/90
Blurs more than 6/90 and at distance
What is the line improvement like for atropine vs patching after 2 years? Which has the faster response?
Theyre both about the same (~3.7 lines)
Patching has a faster response
What is a bangerter/cling foil for amblyopia treatment? What does it cause and what does it generally require?
A blurry film that is stuck to the lens of the dominant eye
Causes the non-dominant eye to fixate distance and near
Generally requires 6/12 visiond
Compare the line improvement of bangerter foil to patching (6h) at 24 weeks. Which was more acceptable?
Patching had better improvement vs bangerter foil
Bangerter foil was more acceptable
