Efficacy of Intermittent Occlusion Therapy Glasses for Amblyopia

This study is designed to evaluate the effectiveness of a novel amblyopia treatment - Intermittent occlusion therapy (IO-therapy) glasses (AmblyzTM) in treating severe amblyopia.

Children ages 3 to 8 years with severe amblyopia (visual acuity of 20/100 to 20/400 in the amblyopic eye) will be enrolled and randomized into two groups: 1) standard 6-hour patching group or 2) 12-hour IO-therapy glasses group.

The study also observe the effectiveness of IO-therapy glasses on two types of difficult amblyopia: deprivation amblyopia associated with congenital or developmental cataract, and myopic anisometropic amblyopia.

Children ages 3 to \< 8 years with severe/dense amblyopia (visual acuity of 20/100 to 20/400 in the amblyopic eye) will be enrolled and randomized into two groups: 1) standard 6-hour patching group or 2) 12-hour IO-therapy glasses group.

Children ages 3 to \< 8 years with deprivation amblyopia associated with congenital or developmental cataracts (visual acuity of 20/40 to 20/400 in the amblyopic eye) will be enrolled.

Children ages 3 to \< 8 years with myopic anisometropic amblyopia will be enrolled into an intermittent occlusion therapy glasses (AmblyzTM) group.

According to visual acuity, they will receive one of two IO-therapy glasses treatment regimens: 1) If the amblyopic eye is between 20/40 to 20/80 inclusive, 4-hour IO-therapy glasses or 2) If the amblyopic eye is between 20/100 to 20/400 inclusive, the child will receive12-hour IO-therapy glasses.

Eligibility Criteria:
Inclusion Criteria:

1. Age 3 to \< 8 years
2. Amblyopia associated with strabismus, anisometropia, or both
3. Visual acuity, measured in each eye without cycloplegia within 7 days prior to enrollment using the ATS single-surround HOTV letter protocol as follows:

   * Visual acuity in the amblyopic eye between 20/100 and 20/400 inclusive
   * Visual acuity in the sound eye 20/32 or better
4. Spectacle correction (if applicable) for measurement of enrollment visual acuity must meet the following criteria and be based on a cycloplegic refraction within 6 months:

   * Requirements for spectacle correction:
   * For patients meeting criteria for only strabismus i. Hypermetropia if corrected must not be undercorrected by more than +1.50 D spherical equivalent, and the reduction in plus sphere must be symmetric in the two eyes. Otherwise, spectacle correction is at investigator discretion.
   * For patients meeting criteria for anisometropia or combined-mechanism i. Spherical equivalent must be within 0.50 D of fully correcting the anisometropia ii. Hypermetropia must not be undercorrected by more than +1.50 D spherical equivalent, and reduction in plus must be symmetric in the two eyes iii. Cylinder power in both eyes must be within 0.50 D of fully correcting the astigmatism iv. Cylinder axis in the spectacle lenses in both eyes must be within 6 degrees of the axis of the cycloplegic refraction
5. Wearing optimal spectacle correction for a minimum of 4 weeks at the time of enrollment.
6. Gestational age \> 34 weeks and birth weight \> 1500 grams
7. Parent willing to accept randomization
8. Parent willing to be contacted and has access to phone
9. Parent does not anticipate relocation outside area of active study site

Exclusion Criteria:

* • Amblyopic eye has myopia worse than -3.00D spherical equivalent.

  * Previous amblyopia treatment within 6 months.
  * Prior intraocular or refractive surgery
  * Known skin reactions to patch or bandage adhesives
  * Systemic diseases that may cause reduced vision such as Down syndrome.

If patients are in the deprivation amblyopia category, the following criteria must be met for the patient to be enrolled in the study:

1. Age 3 to \< 8 years
2. Amblyopia due to previous congenital or developmental cataract surgery.
3. Visual acuity, measured in each eye without cycloplegia within 7 days prior to enrollment using the ATS single-surround HOTV letter protocol as follows:

a. Visual acuity in the amblyopic eye between 20/40 and 20/400 inclusive b. Visual acuity in the sound eye 20/32 or better c. Inter-eye acuity difference ≥ 2 logMAR lines (i.e., amblyopic eye acuity at least 3 lines worse than sound eye acuity) d) Gestational age \> 34 weeks and birth weight \> 1500 grams e) Parent willing to be contacted and has access to phone.

If patients are enrolled in the myopic anisometropia amblyopia category, the following criteria must be met for the patients to be enrolled in the study.

* Aged 3 to \<8 years
* Best-corrected VA in the amblyopic eye of 20/40 to 20/400 inclusive
* Best-corrected VA in the fellow eye of 20/40 or better
* Magnitude of myopic anisometropia of \> 3.00 D
* Intereye acuity difference of \> 3 logMAR lines
* Amblyopia associated with myopic anisometropia
* Has been wearing optimal spectacle correction for a minimum of four weeks