Dichoptic Treatment for Amblyopia in Children 8 to 12 Years of Age

Eligibility Criteria

• 1. Age 8 to \<13 years.
• 2. VA, measured in each eye without cycloplegia in current refractive correction (if applicable) using the E-ETDRS 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 (33 to 72 letters with E-ETDRS).
• 2. VA in the fellow eye 20/25 or better (≥ 78 letters with E-ETDRS).
• 3. Interocular difference ≥ 3 logMAR lines (≥ 15 letters) i.e., amblyopic eye VA at least 3 logMAR lines worse than fellow eye VA).
• 3. 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 \<=5 prism diopters (∆) by SPCT at distance and near fixation.
• * Documented history of strabismus which is no longer present (which in the judgment of the investigator could have caused amblyopia).
• 2. Criteria for anisometropia: At least one of the following criteria must be met:
• * ≥1.00 D difference between eyes in spherical equivalent (SE).
• * ≥1.50 D difference in astigmatism between corresponding meridians in the two eyes.
• 3. Criteria for combined-mechanism: Both of the following criteria must be met:
• * A criterion for strabismus is met (see above).
• * ≥1.00 D difference between eyes in SE OR ≥1.50 D difference in astigmatism between corresponding meridians in the two eyes.
• 4. No more than 2 weeks (cumulative) of prior dichoptic treatment
• 5. No treatment with cycloplegic eyedrops (e.g., atropine) in the past 2 weeks; other treatments allowed up to enrollment but then must be discontinued.
• 6. 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
• 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 +/- 10 degrees if cylinder power is ≤1.00D, and within +/- 5 degrees if cylinder power is \>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.
• 2. Spectacles/contact lens correction (with or without other treatment such as patching) meeting the above criteria must be worn:
• * For at least 18 weeks OR until VA stability is documented (defined as \<1-line change by the same testing method measured on 2 consecutive exams at least 9 weeks apart).
• * For determining VA stability (non-improvement):
• * The first of two measurements may be made 1) in current correction, or 2) in trial frames with or without cycloplegia or 3) without correction (if new correction is prescribed),
• * The second measurement must be made without cycloplegia in the correct spectacles/contact lens correction that has been worn for at least 9 weeks.
• * NOTE: Because this determination is a pre-randomization, the method of measuring VA is not mandated.
• 7. Participant is willing to wear a headset.
• 8. Participant is willing to continue full-time spectacles/contact lens wear (if needed).
• 9. Interpupillary distance of 52mm to 72mm inclusive.
• 10. Investigator is willing to prescribe continued spectacles/contact lens correction (if needed) or either dichoptic device per protocol.
• 11. Participant is willing to accept assignment to either continued spectacles/ contact lens wear alone, dichoptic movies/shows (view 1 hour per day 6 days per week) OR dichoptic games (play approximately 25 minutes per day, 6 days per week) for 19 weeks.
• 12. Parent understands the protocol and is willing to accept randomization.
• 13. Parent has phone (or access to phone) and is willing to be contacted by JAEB Center staff.
• 14. Relocation outside of area of an active PEDIG site for this study within the next 36 weeks is not anticipated.
• 1. Heterotropia more than 5∆ at distance or near (measured by SPCT in current correction)
• 2. Prism greater than a total of 8 diopters horizontal and 1 diopter vertical in the refractive correction at time of enrollment.
• 3. Current bifocal spectacles (eligible only if bifocal discontinued 2 weeks prior to enrollment).
• 4. Myopia greater than -6.00D spherical equivalent in either eye.
• 5. Ocular co-morbidity that may reduce VA determined by an ocular examination performed within the past 7 months (Note: nystagmus per se does not exclude the participant if the above visual acuity criteria are met using patch occlusion. Fogging is not permitted).
• 6. Diplopia more than once per week over the last week prior to enrollment by parental report.
• 7. History of light-induced seizures.
• 8. Known simulator sickness.
• 9. Severe developmental delay that would interfere with treatment or evaluation (in the opinion of the investigator). Participants with mild speech delay or reading and/or learning disabilities are not excluded.
• 10. Immediate family member (biological or legal guardian, child, sibling, parent) of investigative site personnel directly affiliated with this study or an employee of the JAEB center for Health Research.