BVP - Treatment of Amblyopia - Week 3

Question 1

How is occlusion for amblyopia treatment done, what does it force, and what does it inhibit?

Answer 1

Occluding the dominant eye

• forces the non-dominant eye to take up fixation
• reduces the dominant eye’s inhibition of amblyopic eye

Question 2

List four types of occluders. Note which is not recommended and which is used in special cases.

Answer 2

3M opticlude patches
Material ‘over the spectacle’ patches
Opaque material stuck to spectacle lens - not recommended
Black contact lenses - special cases

Question 3

What does full time occlusion entail? Does prescribing less than this achieve adequate results?

Answer 3

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

Question 4

Is full time occlusion the mainstream approach?

Answer 4

Until very recently

Question 5

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.

Answer 5

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

Question 6

Is improvement in acuity with amblyopia treatment symptomatic or asymptomatic?

Answer 6

Asymptomatic

Question 7

Do children as old as 12 respond as well as younger children to amblyopia treatment? Explain (3).

Answer 7

Yes but:

• response not as good
• response is slower
• compliance is poorer

Question 8

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

Answer 8

6/6 - 53%
6/9+ - 73%
6/12 - 87%

Question 9

What is the compliance thought to be for full time occlusion?

Answer 9

~50%

Question 10

Is compliance better or worse in lower socioeconomic groups?

Answer 10

Worse

Question 11

Is compliance higher or lower in private practice?

Answer 11

Higher, allegedly

Question 12

List four tips to improve occlusion compliance.

Answer 12

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

Question 13

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.

Answer 13

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

Question 14

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?

Answer 14

It improves further

Question 15

Define recidivism. When is it more (2) and less likely (1)?

Answer 15

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

Question 16

Up to what age can recidivism occur?

Answer 16

Up to age 11

Question 17

What is the incidence of recidivism after treatment is ceased (percentage)?

Answer 17

Up to 24%

Question 18

What can be a way to detect recidivism? Give a guideline.

Answer 18

Review after a month after treatment stopped
Guideline schdeule:
1 month, 3 months, 6 months, then yearly

Question 19

What is meant by maintenance therapy for recidivism?

Answer 19

If they have optical penalisation for a year or more, then anecdotally no recidivism

Question 20

What is failure of amblyopia treatment defined as?

Answer 20

Less than 6/12 acuity

Question 21

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.

Answer 21

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

Question 22

Describe what penalisation for amblyopia does, what it removes, and whether it affects distance or near.

Answer 22

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

Question 23

Can penalisation be done with dense amblyopia?

Answer 23

No, it will not work

Question 24

What does penalisation require of the non-dominant eye?

Answer 24

‘adequate’ vision

Question 25

Describe the left/right hand analogy to how penalisation may work.

Answer 25

How great an injury do you need to your right hand to use your left instead?

Question 26

How much do you need to blur the dominant eye for them to swap fixation with an amblyopic eye of 6/18 acuity?

Answer 26

3 or more lines of blur

Question 27

How can you tell if an amblyopic patient has swapped fixation?

Answer 27

Measure binocular acuity, then each eye

-if the eyes are still straight

Question 28

List three types of penalisation.

Answer 28

Fogging
Atropine
Bangerter/Cling foils

Question 29

Describe how fogging penalisation is done. What acuity level does it generally need and why?

Answer 29

+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)

Question 30

When doing fogging penalisation, which eye will fixate at near?

Answer 30

The dominant eye

Question 31

What is the compliance of fogging penalisation like?

Answer 31

97%

Question 32

Describe atropine penalisation.

Answer 32

Amblyopia treatment primarily by blurring dominant eye at near

Question 33

Can atropine penalisation be used on most amblyopes?

Answer 33

Yesd

Question 34

In what demographic of patients is atropine penalisation most useful?

Answer 34

In children younger than 2.5 years of age who wont wear a patch

Question 35

Does atropine sting?

Answer 35

No

Question 36

What does an emmetrope blur to at near with atorpine? What about if they are hyperopic (including latent)?

Answer 36

6/90

Blurs more than 6/90 and at distance

Question 37

What is the line improvement like for atropine vs patching after 2 years? Which has the faster response?

Answer 37

Theyre both about the same (~3.7 lines)

Patching has a faster response

Question 38

What is a bangerter/cling foil for amblyopia treatment? What does it cause and what does it generally require?

Answer 38

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

Question 39

Compare the line improvement of bangerter foil to patching (6h) at 24 weeks. Which was more acceptable?

Answer 39

Patching had better improvement vs bangerter foil

Bangerter foil was more acceptable