Patching for Lazy Eye: Trial to Evaluate Daily Patching Amounts
Condition: Amblyopia
MeSH terms: Amblyopia
Study type: Interventional
Phase: Phase 1

Summary: 
      Amblyopia ('lazy eye') is the commonest visual disorder of childhood and is caused by an
      interruption to visual development. Occlusion of the better eye by patching is the mainstay
      of treatment, so forcing use, of the affected eye. We have little understanding of how much
      treatment is required for improvement, so occlusion may continue for many months. This is
      both demanding for the child and family as a whole. Treatment outcome is frequently
      unsatisfactory. Compliance is often poor, thus we do not know precisely how much treatment
      the child actually receives or how much is required.

      To overcome this, we have designed an instrument that permits us to measure occlusion: an
      occlusion dose monitor (ODM) which provides an objective record of how much occlusion a child
      actually receives. Recently we have observed that 75% of improvement induced by occlusion
      occurs in the first four weeks of treatment. In this study we explore the possibility that by
      intensive treatment the period of amblyopia therapy can be shortened - i.e. treatment will be
      more efficient, more effective, and more 'family-friendly'. The study hypothesis is that 12
      hours/day of patching is more effective than 6 hours/day.
    

Detailed description: 
      The identification and subsequent management of amblyopia are major consumers of health
      service resource, and within the hospital sector account for around 80-90% of visits to the
      children's eye service. Occlusion of the better eye is the mainstay of treatment and because
      we have little understanding of the dose-response relationship this may continue for many
      months and sometimes for many hundreds of hours. This is demanding for the child and family
      as a whole and yet the outcome is frequently unsatisfactory. Currently, there is no reliable
      data on the kinetics of visual improvement, so occlusion tends to be prescribed on an ad hoc
      basis. Recent pilot research has shown that 75% of the treatment-generated improvement occurs
      within the first 4 weeks when 6 hours/day occlusion is prescribed.

      In this study we explore the possibility that by intensive treatment the period of amblyopia
      therapy can be shortened - i.e. made both more efficient and hopefully more effective. The
      purpose of the present study, the Randomized Occlusion Treatment of Amblyopia Study (ROTAS),
      is to compare two frequently employed patching regimens: 'substantial' (6 hrs/day) against
      'maximal' (12 hrs/day) patching. Our experimental design incorporates objective occlusion
      monitoring and is able to discriminate the beneficial effect of refractive correction from
      that of occlusion. The study comprises three phases: 'baseline', 'refractive adaptation' and
      'occlusion.' Our aim is to provide guidelines for patient management based, for the first
      time, on experimentally determined and statistically verifiable relationships between
      treatment and outcome.
    

Intervention name(s): 6 hours occlusion by patching; 12 hours occlusion by patching
Intervention type(s): Device; Device
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Amblyopia; Occlusion dose monitoring; Refractive adaptation; Dose-response