Augmenting Atropine Treatment for Amblyopia in Children 3 to < 8 Years Old

This study is designed to evaluate the effectiveness of adding a plano lens to weekend atropine after visual acuity has stabilized with weekend atropine but amblyopia is still present. Children ages 3 to \<8 years with visual acuity of 20/50 to 20/400 in the amblyopic eye will be enrolled in a run-in phase with weekend atropine until no improvement, followed by randomization of eligible patients to weekend atropine treatment with a plano lens over the sound eye versus without a plano lens over the sound eye. The primary objective is to determine if adding a plano lens to weekend atropine will improve visual acuity in patients with amblyopia still present after visual acuity has stabilized with initial treatment.

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.1 Many practitioners prescribe weekend atropine as initial therapy for amblyopia. However, many children fail to achieve normal visual acuity in the amblyopic eye after treatment with this regimen. In a randomized trial conducted by PEDIG comparing atropine regimens, 58 of 83 patients with moderate amblyopia (70%) had amblyopic eye visual acuity of 20/32 or worse after 4 months of treatment with weekend atropine.2 In another PEDIG randomized trial comparing atropine with a plano lens versus without a plano lens for initial treatment of amblyopia, 60 of 84 patients with moderate amblyopia (71%) had amblyopic eye visual acuity of 20/32 or worse after 16 weeks of treatment with weekend atropine.3 When improvement stops after initial therapy and amblyopia is still present, treatment options include increasing the dosage of current treatment, switching to another treatment, maintaining the same treatment and dosage, or combining treatments. Many clinicians will add a plano lens over the sound eye to atropine treatment, in part because families using atropine have become comfortable with its use. This option is limited to children with hypermetropia in the sound eye. However, it is unknown whether adding a plano lens over the sound eye will improve amblyopic eye visual acuity more than continuing atropine alone in patients who have shown no improvement after initial treatment with atropine. In a PEDIG randomized trial comparing patching to atropine for initial treatment of amblyopia, a plano lens was prescribed for the sound eye for 55 patients who had not improved to 20/30 or at least 3 lines after 4 months of daily atropine use.1, 4 Their mean acuity improvement prior to using the plano lens was 1.0 line, compared with 1.6 lines after prescribing the plano lens. We are unaware of any reports of the response of treatment of amblyopia still present after initial treatment with weekend atropine.

Eligibility Criteria:
Inclusion Criteria:

Major Eligibility Criteria for Run-in Phase

* Age 3 to \< 8 years
* Amblyopia associated with strabismus, anisometropia, or both
* Visual acuity in the amblyopic eye between 20/50 and 20/400 inclusive
* Visual acuity in the sound eye 20/32 or better and inter-eye acuity difference \>3 logMAR lines
* Amblyopia treatment within the past 6 months subject to the following stipulations:

  * No more than 6 weeks of any amblyopia treatment other than spectacles (except for patients being treated with atropine who are entering the study on treatment)
  * No simultaneous treatment with patching and atropine
  * No use of atropine in combination with the sound eye spectacle lens reduced by more than 1.50 D
  * Maximum level of treatment within the past 6 months:

    * Patching: up to 2 hours daily
    * Atropine: up to once daily
* Wearing spectacles with optimal correction (if amblyopic eye acuity is 20/80 or better, then VA must be stable in glasses; if amblyopic eye acuity is 20/100 or worse, then spectacles and atropine can be initiated simultaneously).
* Hypermetropia and spectacle correction in sound eye of +1.50 D or more

Eligibility Criteria for Randomization:

* Amblyopic eye acuity of 20/40 to 20/160 with an inter-ocular difference of \>2 lines, or amblyopic eye acuity of 20/32 with 3 lines of IOD.
* Compliance with weekend atropine treatment based on investigator judgment.

Exclusion Criteria:

* Currently using vision therapy or orthoptics
* Ocular cause for reduced visual acuity (nystagmus per se does not exclude the patient if the above visual acuity criteria are met)
* Prior intraocular or refractive surgery
* Known allergy to atropine or other cycloplegic drugs
* Down Syndrome present