At the time of enrollment, individuals must meet all the following inclusion criteria to be eligible to participate in the study.

1. Age 4 to 7 years.
2. Visual acuity, measured in each eye without cycloplegia in current refractive correction (if applicable) using the ATS-HOTV VA protocol on a study-approved device displaying single surrounded optotypes, as follows:

1. VA in the amblyopic eye 20/40 to 20/200 inclusive.
2. Age-normal VA in the fellow eye:44,45

-4 years: 20/40 or better; 5-6 years: 20/32 or better; 7 years: 20/25 or better

1. Interocular difference greater than or equal to 3 logMAR lines (i.e., amblyopic eye VA at least 3 logMAR lines worse than fellow eye VA).

1. Amblyopia associated with strabismus, anisometropia, or both (previously treated or untreated).

1. Criteria for strabismic amblyopia: At least one of the following must be met:

• Presence of a heterotropia on examination at distance or near fixation (with optical correction), must be less than or equal to 5 prism diopters by SPCT at distance and near fixation (see #7 below).
• Documented history of strabismus which is no longer present (which in the judgment of the investigator could have caused amblyopia).

1. Criteria for anisometropia: At least one of the following criteria must be met:

• Greater than or equal to 1.00 D difference between eyes in spherical equivalent (SE).
• Greater than or equal to 1.50 D difference in astigmatism between corresponding meridians in the two eyes.

1. Criteria for combined-mechanism: Both of the following criteria must be met:

• A criterion for strabismus is met (see above).
• Greater than or equal to 1.00 D difference between eyes in spherical equivalent OR greater than or equal to 1.50 D difference in astigmatism between corresponding meridians in the two eyes.

1. No more than 2 weeks (cumulative) of prior dichoptic treatment.
2. No treatment with cycloplegic eyedrops (e.g., atropine) in the past 2 weeks; other treatments allowed up to enrollment but then must be discontinued.
3. Refractive correction is required (single vision lenses or contact lenses) for any of the following refractive errors based on a cycloplegic refraction completed within the last 7 months:

• Hypermetropia of 2.50 D or more by SE
• Myopia of amblyopic eye of 0.50D or more SE
• Astigmatism of 1.00D or more
• Anisometropia of more than 0.50D SE

NOTE: Monocular or binocular contact lens wear is allowed provided the contact lenses meet the refractive error correction requirements below. For each child, all testing must be performed using the same form of optical correction (i.e., no changing between contacts and spectacles).

1. Spectacles/contact lens correction prescribing instructions referenced to the cycloplegic refraction completed within the last 7 months:

• SE must be within 0.50D of fully correcting the anisometropia (if new glasses are prescribed, reduction in plus sphere must be symmetric in the two eyes).
• SE must not be under corrected by more than 1.50D SE.
• Cylinder power in both eyes must be within 0.50D of fully correcting the astigmatism.
• Axis must be within plus or minus 10 degrees if cylinder power is less than or equal to 1.00D, and within plus or minus 5 degrees if cylinder power is greater than 1.00D.
• Myopia must not be under corrected by more than 0.25D or over corrected by more than 0.50D SE, and any change must be symmetrical in the two eyes.

Note: Other protocol defined Inclusion/Exclusion criteria may apply