amblyopia evidence

tx time

Dose-effect relationship (MOTAS, 2004)

• 82% of improvement occurred in the first 6

  weeks of treatment (almost all improvement had

  occurred after 12 weeks

Stewart et al, 2005

• No further improvement over 4 hours of actual wear – but need to prescribe 6 hours

occlusion time - how long

pedig - repka et al 2003

• 2hr vs 6hr -

supervision during occlusion

• time of appointment

• impact of age

• amount of occlusion

• effect of compliance

• encouragement

• monitoring

other consideration

• reaction to patch

• coping with VA

• compliance

• psychological aspects

atropine

• pedig 2004

  • Comparison of daily atropine

    with atropine installed twice

    weekly (i.e. at weekend)

    Both groups showed the same

    improvement in acuity

• Pedig 2002

  • Comparison of occlusion (≥6hrs per day) vs. 1 drop

    After 6 months follow up no significant difference in improvement in acuity

    Occlusion group showed faster response though – after 5 weeks, 2.22 lines occlusion and 1.37 lines atropine

pedig 2009 - amblyopia

Severe amblyopia (20/125-20/400) (6/37.5-3/60)

Trial 1: Comparison of wk end atropine plus plano vs. wk end atropine and full correction (age 3-6yrs)

Trial 2: Wk end atropine vs. 2 hours occlusion (age 7-12 yrs) criteria: strabismic and/or anisometropic

amblyopes age 3-7 years

No difference in outcome in either trial

Greater improvement in the younger group vs. older group

Conclusion atropine is effective

Refractive adaptation

Moseley et al. 2002, Stewart et al. 2004)

• ge 3-8 years

  Acuity 0.1-1.6 LogMAR

• Mean improvement ‘glasses only’ 0.24 LogMAR

• No difference in response between pure anisometropes or

  those with associated strabismus

• Mean time to best acuity 14 weeks (up to max of 18 wks)

  22% of children required no occlusion after refractive

  adaptation

pedig 2002,2003,2004 - age of tx

• no effects of age in relation to outcome

Clarke et al (2003) - age of tx

reported no difference in the outcome in children where treatment was delayed by 12 months (treatment undertaken by 5 years),

MOTAS (2004) - age of tx

improvements in VA increased significantly with decreasing age (under 4 years vs. 4- 6 years vs. 6yrs+)

critical age period - PEDIG (2005)

500+ strab and aniso amblyopes age 7-17 years PEDIG (2005)

Treatment of optical correction RCT with or without additional 2-6 hours occlusion

(7-12 yr olds also had atropine penalisation)

Improvement considered to be significant if acuity increased by 2 lines by the final

follow up after 24 weeks

24% of those with optical correction alone showed significant improvement

53% of 7-12 year olds significant improvement, but only 25% in 13-17 year age group

(though if not previously treated for amblyopia 47% improved)

Hess 2010 - age of tx

• 33-45 yrs some improvement possible

Binoc tx

Parts of the visual scene only visible to amblyopic eye - I BIT

Herbison et al (2013)

Interactive binocular tx for amblyopia

• Computer games

• Binocular treatment (less detailed

  image to FE)

Binoc TX - PEDIG (2016)

• RCT binocular treatment iPad vs occlusion

• Non-inferiority trial – aim is to prove that a novel treatment is not inferior to an actively used standard treatment

Compliance poor (probably with both)

• VA improvement with the iPad treatment was not as effective as 2 hours occlusion

Binoc tx - Kelly et al. (2018)

• Binocular treatment games/movies

• 1 hour a day, 5 days a week for 2 weeks (10 hours total) or

• movie (9 hours total – 6 visits)

• 6 strabismic, 21 aniso, 14 mixed

• Mean ± SD amblyopic eye BCVA improvement from baseline to the 2-week visit with binocular

• treatment was 0.14 ± 0.09 logMAR (1.4 ± 0.9 lines)

• Some improvements in stereo also

  • Note variability in improvement

  • Ongoing study only short follow up

penalisation

Lenses/cycloplegic drugs

Total - High convex lens (+/- atropine)

Most likely use is to enhance effect of atropine – reduce

Hm correction or give plano to FE

Other options: Levodopa-Carbidopa

Neurotransmitter

Increases dopamine levels

• Parkinson’s Disease

• Small improvements found in VA & CS? Maintained

• Side effects mental disturbances, bleeding and bruising, palpitations, uncontrolled movements, fatigue, dizziness, vivid dreams

• RCT PEDIG (2015) for residual amblyopia: no extra improvement when combined with 2hrs occlusion vs placebo

points to consider when using occlusion

What is their age and relation to the critical periods

Indicators of prognosis

Latent nystagmus - partial occlusion or atropine both eyes 2/52

Compliance and how to improve

Risk of intractable diplopia

Effect of Amblyopia Treatment On Suppression Study (EATOSS) –

Newsham & O’Connor

• Effect of occlusion on the density suppression

• Any association with other factors

• Age of patient

• Degree of amblyopia/Amount of occlusion prescribed

• Angle of strabismus

Amblyopia in congenital cataracts

Unilateral vs bilateral

Optical treatment implications

Orthoptic input prior to cataract removal

Risk of high doses

◦ Based on proportion of waking hours

◦ Related to age

Duration

End point

PEDIG paediatric cataract studies

compliance

• MOTAS (2004) – average compliance 48%

• Loudon et al. (2003) ODM compliance rate 80% in those

  • where acuity improved satisfactorily and 34% where

  • acuity improvement was unsatisfactory

• Dixon-woods et al. (2006) interviewed parents –

  • sometimes confused by information given in clinic, generally felt treatment was credible, tended not to comply if VA not seen to improve, or if child was suffering socially or educationally

future issues

Binocular treatments???

Conflict on the effect of age when treated and outcome -

screening

Plasticity in older children/adults

Why are some amblyopes resistant to treatment – poor

overall success rate

Recurrence of amblyopia over long term follow up

Implementation of research findings into practice

Impact on clinical practice

• Effect of research regarding patching regimens (PEDIG)
  

• Wygnanski-Jaffe (2005)

Questionnaire to 380 ophthalmologists

• 90 responded (23.8%)

• 13% were not aware of the study

• 39% made no change whatsoever to their practice

• 33% made adjustments rarely

• 12% made changes in response to the findings

• 3% used atropine only

Impact on clinical practice - Newsham (2010, British Journal of Ophthalmology) – no further updates

Questionnaire to UK Orthoptists

Wide range of clinical practice and 60% sometimes occluded in excess of 6 hours

Most considered occlusion to be more effective than atropine

Only 9% would use atropine as a first line treatment

34% allowed 8wks or less for refractive adaptation

25% never gave written information to parents

33% made no change whatsoever to their practice in relation to the recent research

Amblyopia in adults without strabismus

Six themes emerged:

(1) symptoms experienced by participants,

(2) concerns and apprehensions,

(3) emotional impacts,

(4) activity limitations,

(5) hassle and inconveniences

(6) economic and career implications