Bilateral and Unilateral Amblyopia Treatment Study

Inclusion Criteria: * Age 3 to \< 10 years * Subjects and their parent/guardian speak and understand English adequately to complete the study protocol and give informed consent. Subjects have the ability to adhere to the study visit schedule. * All refractive error measures below will be determined by cycloplegic retinoscopy by one of the study investigators during the comprehensive eye exam. Measures are in minus cylinder spectacle prescription format. Inclusion criteria for bilateral amblyopia: The major eligibility criteria include: * Best-corrected visual acuity of \<20/30 each eye. * For hypermetropia: * Spherical equivalent \>+2.00 D each eye. * Spherical equivalent difference between eyes \<1.25 D. * For astigmatism without hypermetropia criteria above or myopia criteria below: * \>1.75 D each eye * Difference between eyes \<1.25 D * For myopia: * Spherical equivalent \<-5.00. * Spherical equivalent difference between eyes \<1.25 D. Inclusion criteria for unilateral amblyopia: The major eligibility criteria include: * Presence of anisometropia or constant unilateral strabismus. * Best-corrected visual acuity in the amblyopic eye \<20/30; and interocular difference of best-corrected visual acuity at least two logMAR lines. * For anisometropia: * Spherical equivalent ≥ 1.00 D interocular difference * Astigmatism \>1.75 D interocular difference * For constant unilateral strabismus where spectacle prescription is indicated. Examples where spectacle prescription is indicated include esotropia caused at least in part by an accommodative component or where significant refractive error in either eye warrants spectacle prescription for improved vision. Exclusion Criteria: * History of spectacle wear * Previous treatment for amblyopia * Active amblyopia treatment planned other than spectacles at enrollment * Prior intraocular or refractive surgery * Ocular or systemic abnormalities that the examining investigator deems could impact prognosis for visual improvement. Examples could include birth history that may have affected brain development, extremely low birth weight (\<1.5 lbs), seizure disorders, cerebral palsy, optic nerve hypoplasia, cranial nerve palsy. Examples that would usually not exclude are off axis media opacity, low birth weight (2.0-3.5 lbs) without complication, mild limitation of extraocular muscle. Cognitive impairment that prohibits accurate data collection