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

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.

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