Trial Comparing Patching Versus Atropine for Amblyopia in 7 to < 13 Year Olds
Condition: Amblyopia
MeSH terms: Amblyopia
Study type: Interventional
Phase: Phase 3

Summary: 
      The purpose of this study is:

        -  To compare the effectiveness of weekend atropine plus near activities and daily patching
           plus near activities for moderate amblyopia (20/40 to 20/100) and severe amblyopia
           (20/125 to 20/400) in improving vision in the amblyopic eye of 7 to <13 year olds.

        -  To determine the maximum improvement in vision of the amblyopic eye with each treatment.

        -  To determine whether amblyopia is associated with structural abnormalities of optic
           nerve fiber layer.
    

Detailed description: 
      Although there is consensus that amblyopia can be treated effectively in young children, many
      eye care practitioners believe that treatment beyond a certain age is ineffective. Some
      clinicians have believed that a treatment response is unlikely after the age of 6 or 7 years,
      while others have considered age 9 or 10 years to be the upper age limit for successful
      treatment. The American Academy of Ophthalmology Preferred Practice Pattern for amblyopia
      recommends treatment up to age 10 years. The opinion that amblyopia treatment is ineffective
      in older children may have arisen because the age of 6 to 7 years is thought to be the end of
      the "critical period" for visual development in humans. This belief, however, was not based
      on adequate prospectively-collected data.

      To address this issue of the response of amblyopia to treatment in children 7 years and
      older, the Pediatric Eye Disease Investigator Group (PEDIG) conducted a randomized trial of
      507 patients (aged 7 to <18 years) with amblyopic eye visual acuity ranging from 20/40 to
      20/400. Patients were provided with optimal optical correction and then randomized to a
      Treatment Group (2 to 6 hours per day of prescribed patching of the sound eye combined with
      near visual activities for all patients plus atropine one drop per day in the sound eye for 7
      to <13 year olds) or an Optical Correction Group (optical correction alone). Patients whose
      amblyopic eye acuity improved 10 or more letters (2 lines) by 24 weeks were considered
      responders. In the 7 to <13 year olds (N=404), 53% of the Treatment Group were responders
      compared with 25% of the Optical Correction Group (P<0.001). In the 13 to <18 year olds
      (N=103), the responder rates were 25% and 23% respectively overall (adjusted P=0.22), but 47%
      and 20% respectively among patients not previously treated with patching and/or atropine for
      amblyopia (adjusted P=0.03). Most patients, including responders, were left with a residual
      visual acuity deficit.

      The use of multiple modalities (patching, atropine, near visual activities) in the treatment
      regimen for the 7 to <13 year olds in this trial (ATS3) was an effort to maximize the
      therapeutic response. Patients age 13 years and older were prescribed patching but not
      atropine because of concern that the continual optical blur from the atropine could have a
      deleterious effect on their ability to drive and perform other activities. Prescribed
      patching was 2 to 6 hours a day to limit patch wear to non-school hours and because our prior
      studies of 3 to <7 year olds demonstrated that as little as two hours of patching a day (when
      combined with near visual activities) is as effective as a greater number of hours.
      Instructing patients to perform at least one hour of near activities while wearing the patch
      was based on the unproven clinical opinion that near activities can augment the effect of the
      occlusion therapy. A PEDIG pilot study suggested that near activities are beneficial and this
      question of benefit of near activities is currently being studied in another randomized
      clinical trial. Atropine placed in the sound eye once a day and two days a week has been
      demonstrated in younger children to be beneficial to the acuity of the amblyopic eye,
      presumably due to its cycloplegic effect of blurring vision in the sound eye especially at
      near fixation. In a study comparing daily and weekend atropine, daily atropine was not found
      to be superior.

      The unanswered question from this completed clinical trial is whether prescribing patching or
      atropine alone could have produced a response similar to the combination therapy, or whether
      in this age group, one treatment is better than the other. A poll of PEDIG investigators at
      an investigator meeting on January 15, 2005 indicated that very few are following the
      treatment regimen used in the prior study (ATS3); rather, most are prescribing
      monotherapy-either patching or atropine-as the initial treatment for amblyopia in the 7 to
      <13 year age range. Thus, a trial comparing atropine and patching as amblyopia treatments in
      7 to <13 year olds is needed.

      The study has been designed as a simple trial that, other than the type of amblyopia therapy
      being determined through the randomization process, approximates standard clinical practice.
      The two treatment regimes are: 1) Atropine 1% once each weekend day in the sound eye plus
      near activities for at least one hour every day without the aid of reading glasses (with
      increase to daily atropine at 5 weeks if acuity not improved by at least 5 letters) and 2)
      Patching 2 hours per day plus near activities for one hour while patching (with increase to 4
      hours per day for moderate amblyopes and > 4 hours per day for severe amblyopes at 5 weeks if
      acuity not improved by at least 5 letters).

      Optional Ancillary Study As part of the optic nerve imaging ancillary study, retinal nerve
      fiber layer imaging using optical coherence tomography will be performed on some patients.
      This will be optional for patients at participating sites. The procedure is not part of
      standard care. The subject's pupils will need to be dilated, if not already dilated as part
      of the exam. Testing of both eyes can be completed in about 15 minutes.
    

Intervention name(s): Atropine; Patching; Near activities
Intervention type(s): Drug; Device; Procedure
Intervention description(s): Atropine 1% each weekend day in the sound eye; Patching 2 hours per day; near visual activities for at least one hour per day
Other intervention name(s): Coverlet, 3M Opticlude, Ortopad®
Intervention MeSH terms: Atropine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Amblyopia; Atropine; Patching