Trial to Evaluate 2 Hours of Daily Patching for Amblyopia in Children
Condition: Amblyopia
MeSH terms: Amblyopia
Study type: Interventional
Phase: Phase 3

Summary: 
      The objectives of the Spectacle Phase are:

        -  In previously untreated pure anisometropic patients (i.e. patients who have not used
           spectacles in the last year and who do not have strabismus), to determine

             1. the incidence of resolution of amblyopia with spectacle correction alone and

             2. the time course of visual acuity improvement with spectacle correction alone.

        -  In all other patients, to achieve maximal improvement with spectacle correction prior to
           entering the randomized trial.

      The objectives of the Randomized Trial are:

        -  To determine whether 5 weeks of patching treatment (2 hours of patching per day of the
           sound eye combined with at least one concurrent hour of near activities), compared with
           a control group (using spectacle correction only), improves visual acuity in patients
           with moderate to severe amblyopia (20/40 to 20/400).

        -  To determine the maximal improvement and time course of improvement with this patching
           treatment regimen.
    

Detailed description: 
      There are few data on the improvement that occurs with spectacle correction alone in cases of
      anisometropic amblyopia. The only published study of which we are aware is that of Moseley,
      et al, who found that 8 of 12 patients prescribed spectacles for the first time improved 3 or
      more lines in the amblyopic eye. Therefore, the Spectacle Phase of the current study will
      provide important information related to the management of patients with anisometropic
      amblyopia.

      Additionally, despite clinical experience that strongly indicates that amblyopia can be
      improved with treatment, there are those who claim that the benefit of treatment is unproven.
      Although improvement with amblyopia therapy has been shown in prospective trials, there have
      been no conclusive data published from a randomized trial evaluating the effect of amblyopia
      treatment compared with a control group. Therefore, we have designed a randomized trial to
      definitively address this issue.

      In the trial, the effect on amblyopic eye acuity after five weeks of 2 hours of prescribed
      daily patching (combined with at least one hour of concurrent near activities) will be
      compared with a control group using spectacle correction only. In a study conducted by the
      Pediatric Eye Disease Investigator Group, a 2-hour daily patching treatment regimen improved
      moderate amblyopia (20/40 to 20/80) by an amount similar to the improvement seen with 6 hours
      of daily patching.

      At the end of five weeks, patients whose amblyopic eye has improved from baseline will
      continue in follow up, using the assigned treatment, until the amblyopic eye acuity stops
      improving or until the amblyopia resolves. This will provide data on the maximum improvement
      achievable with this treatment regimen and on the time course to reach maximal improvement.
      There is no known harm in deferring treatment of amblyopia for five weeks in the age range to
      be included in the trial (3 to <7 years old). Standard care for a patient with amblyopia
      includes prescribing spectacle correction and having the patient return in 4 to 6 weeks for
      measurement of visual acuity. Spectacles alone are continued as long as the acuity in the
      amblyopic eye is improving. Once the acuity stops improving, occlusion or other active
      treatment is initiated. The maximum delay in active treatment of the control group beyond the
      standard of care is 5 weeks. In our prior Amblyopia Treatment Study protocols on patients in
      this age range, we have found no indication that the response to patching treatment is
      related to age. Therefore, it is highly unlikely that a delay in initiating treatment of
      weeks or even months could be harmful.

      This study is addressing issues related to the treatment of amblyopia in children 3 to <7
      years old with visual acuity 20/40 to 20/400. The study consists of two phases:

        1. a Spectacle Phase in which patients are prescribed spectacles and followed until maximal
           improvement in visual acuity has occurred and

        2. a Randomized Trial comparing a group using patching treatment (in addition to spectacle
           correction) with a control group using spectacle correction only.

      The sample size for the primary analysis for the randomized trial has been estimated to be
      134 patients. Patients will be enrolled into the Spectacle Phase until the recruitment goal
      for the Randomized Trial is reached.
    

Intervention name(s): Eye patch; Spectacles
Intervention type(s): Device; Device
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment