Poor enrollment and infeasibility of ever reaching the necessary sample size

This study is designed to evaluate the effectiveness of treatment of residual amblyopia in children ages 3 to < 10 years with visual acuity of 20/32 to 20/63 in the amblyopic eye. The study is a randomized clinical trial comparing intensive treatment (42 hours per week of patching plus daily atropine) with a control group that will have rapid weaning of existing treatment followed by spectacle correction only (if needed). The primary objective is to determine if this intensive treatment will improve visual acuity in patients with residual amblyopia.

The primary outcome assessment is amblyopic eye visual acuity at 10 weeks.

The primary analytic approach for the amblyopic eye acuity will be a treatment group comparison of the proportion of patients with at least two lines of visual acuity improvement.

Amblyopia is the most common cause of monocular visual impairment in both children and young and middle-aged adults. Both patching and atropine are accepted treatment modalities for the management of moderate amblyopia in children. Despite best efforts with conventional treatment, some patients fail to achieve normal visual acuity in the amblyopic eye. In a randomized trial conducted by PEDIG comparing atropine versus patching in 3 to 6 year olds with moderate amblyopia (ATS1), 261 of 402 patients (65%) had amblyopic eye visual acuity of 20/32 or worse after 6 months of treatment with patching or atropine. Beyond 6 months, treatment was at investigator discretion, and two years after randomization, 181 of 363 children (50%) still had amblyopic eye visual acuity of 20/32 or worse. In a randomized trial conducted by PEDIG comparing patching regimens, 129 of 181 patients with moderate amblyopia (71%) and 145 of 157 patients with severe amblyopia (92%) had amblyopic eye visual acuity of 20/32 or worse after 4 months of occlusion therapy. Many patients receive treatment beyond 6 months but still fail to achieve normal visual acuity in the amblyopic eye. It is unknown whether an intensive "final push" of combined treatment with daily patching and atropine will improve visual acuity in these patients. Although some clinicians prescribe simultaneous patching and atropine for selected patients, there are no published reports of its effectiveness. Also, we are not aware of reports of response to treatment of residual amblyopia.

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. Patients will be randomized to one of two treatment regimens:

• Intensive treatment: 42 hours per week of patching combined with daily atropine (1%)
• Control group: Weaning of the current treatment (two hours of daily patching for patients currently using patching and once weekly atropine for patients currently using atropine) for 4 weeks, then no treatment other than spectacles (if needed).

Inclusion Criteria:

• Age 3 to < 10 years

• Amblyopia associated with strabismus, anisometropia, or both

• Visual acuity in the amblyopic eye between 20/32 and 20/63 inclusive

• Visual acuity in the sound eye 20/32 or better and inter-eye acuity difference >= 2 logMAR lines

• Current/previous treatment with patching and/or atropine subject to the following stipulations:

  • No simultaneous treatment with patching and atropine in the past 6 months

  • No prior use of atropine in combination with the sound eye spectacle lens reduced by more than 1.50 D

  • Maximum level of any previous treatment:

    • Patching: up to 42 hours per week (averaging 6 hours daily)
    • Atropine: up to once daily

  • Current treatment with 42 hours per week patching or daily atropine

• No improvement in best-corrected amblyopic eye visual acuity between two consecutive visits at least 6 weeks apart using the same testing method and optimal spectacle correction (if needed), with no improvement defined as follows:

  • No lines of improvement
  • For patients tested using E-ETDRS, letter score that is no more than 4 letters improved

• Wearing spectacles with optimal correction (if applicable)

• Investigator ready to wean or stop treatment

Exclusion Criteria:

• Current vision therapy or orthoptics
• Ocular cause for reduced visual acuity
• Prior intraocular or refractive surgery
• Strabismus surgery planned within 10 weeks
• Known allergy to atropine or other cycloplegic drugs
• Known skin reactions to patch or bandage adhesives
• Down Syndrome present

10 weeks

This trial was stopped after 18 months due to inadequate recruitment.