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

Inclusion Criteria:

1. Age 8 to <13 years.

2. VA, measured in each eye without cycloplegia in current refractive correction (ifapplicable) using the E-ETDRS VA protocol on a study-approved device displayingsingle surrounded optotypes, as follows:

3. VA in the amblyopic eye 20/40 to 20/200 inclusive (33 to 72 letters withE-ETDRS).

4. VA in the fellow eye 20/25 or better (≥ 78 letters with E-ETDRS).

5. Interocular difference ≥ 3 logMAR lines (≥ 15 letters) i.e., amblyopic eye VAat least 3 logMAR lines worse than fellow eye VA).

6. Amblyopia associated with strabismus, anisometropia, or both (previously treated oruntreated).

7. 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 atdistance and near fixation.
• Documented history of strabismus which is no longer present (which in thejudgment 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 thetwo 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 astigmatismbetween 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; othertreatments allowed up to enrollment but then must be discontinued.

6. Refractive correction is required (single vision lenses or contact lenses) for anyof the following refractive errors based on a cycloplegic refraction completedwithin 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: Children with cycloplegic refractive errors that do not fall within therequirements above for refractive correction may be given refractive correction atinvestigator discretion but must follow the study-specified prescribing guidelines,as detailed below. NOTE: Monocular or binocular contact lens wear is allowed provided the contactlenses meet the refractive error correction requirements below. For each child, alltesting must be performed using the same form of optical correction (i.e., nochanging between contacts and spectacles).

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

• SE must be within 0.50D of fully correcting the anisometropia (if newglasses are prescribed, reduction in plus sphere must be symmetric in thetwo 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 theastigmatism.
• 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 bymore 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 aspatching) 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 examsat 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) withoutcorrection (if new correction is prescribed),
• The second measurement must be made without cycloplegia in thecorrect spectacles/contact lens correction that has been worn for atleast 9 weeks.
• NOTE: Because this determination is a pre-randomization, the methodof 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 (ifneeded).

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/ contactlens wear alone, dichoptic movies/shows (view 1 hour per day 6 days per week) ORdichoptic games (play approximately 25 minutes per day, 6 days per week) for 19weeks.

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 Centerstaff.

14. Relocation outside of area of an active PEDIG site for this study within the next 36weeks is not anticipated.

Exclusion Criteria:

1. Heterotropia more than 5∆ at distance or near (measured by SPCT in currentcorrection)

2. Prism greater than a total of 8 diopters horizontal and 1 diopter vertical in therefractive correction at time of enrollment.

3. Current bifocal spectacles (eligible only if bifocal discontinued 2 weeks prior toenrollment).

4. Myopia greater than -6.00D spherical equivalent in either eye.

5. Ocular co-morbidity that may reduce VA determined by an ocular examination performedwithin the past 7 months (Note: nystagmus per se does not exclude the participant ifthe above visual acuity criteria are met using patch occlusion. Fogging is notpermitted).

6. Diplopia more than once per week over the last week prior to enrollment by parentalreport.

7. History of light-induced seizures.

8. Known simulator sickness.

9. Severe developmental delay that would interfere with treatment or evaluation (in theopinion of the investigator). Participants with mild speech delay or reading and/orlearning disabilities are not excluded.

10. Immediate family member (biological or legal guardian, child, sibling, parent) ofinvestigative site personnel directly affiliated with this study or an employee ofthe JAEB center for Health Research.