Table 1 Inclusion and exclusion criteria

1.

Patient is 7–17 years old.

2.

Amount of exodeviation measured using PACT at 1 month after IXT surgery meets any of the following:

2.1 Exodeviation < 10 PD at near and distance.

2.2 Ortho at near, and exodeviation < 10 PD at distance.

2.3 Ortho at distance, and exodeviation < 10 PD at near.

3.

Best corrected visual acuity (BCVA) in the worse eye is 0.1 logMAR or better and there has been no previous diagnosis or treatment for amblyopia.

4.

Participant wore spectacles for at least 1 week if refractive error meets any of the following:

4.1 Myopia< − 0.50 D and > − 6.00 D SE in either eye.

4.2 Anisometropia < 1.50 D SER.

4.3 No hyperopia of more than + 3.50 D SER in either eye.

5.

Refractive correction for participants meeting the above refractive error criteria must meet the following guidelines:

5.1 For myopia, the intent is to fully correct.

5.2 For hyperopia, the spherical component can be reduced at investigator discretion as the principal of maximum plus to maximum visual acuity.

5.3 For astigmatism, cylinder must be within 0.25 D of full correction and axis must be within 5° of full correction.

5.4 Myopic participants should not take any intervention for myopia control, such as orthokeratology, peripheral defocus lenses, and low-concentrate atropine.

6.

No atropine was used within the previous month.

7.

Patient had gestational age > 34 weeks and birth weight > 1500 g.

8.

Parents and participant understand protocol and are willing to accept randomization to binocular training group or sham-control group.

9.

Patient had not received prior vision training or orthoptics for any reason.

10.

The location of the home address is not very far from the hospital, and if assigned to the training group, training 1–2 times a week at hospital is acceptable.

1.

Coexisting vertical deviation > 5 PD.

2.

Esodeviation > 5 PD at near or distance

3.

Complaints of diplopia 1 month after surgery in the primary and reading positions.

4.

Limitation of ocular rotations resulting from restrictive or paretic strabismus.

5.

Craniofacial malformations affecting the orbits.

6.

Interocular visual acuity difference more than 0.2 logMAR.

7.

High AC/A ratio (exclude > 6:1 by gradient method).

8.

Prior strabismus surgery or botulinum toxin injection.

9.

Prior intraocular or refractive surgery.

10.

Significant neurological impairment such as cerebral palsy. Participants with mild speech or learning disabilities or both are eligible.