Table 1.

Control score description and instructions.

Control Score	Control Score Description
5	Constant exotropia during a 30-second observation period (before dissociation)
4	Exotropia >50% of the time during a 30-second observation period
3	Exotropia <50% of the time during a 30-second observation period
2	No exotropia unless dissociated (10 seconds): recovery in > 5 seconds
1	No exotropia unless dissociated (10 seconds): recovery in 1–5 seconds
0	Pure phoria: < 1 second recovery after 10-second dissociation
Instructions:
The control scale is for both distance (3m) and near (1/3m) fixation, which combined, yields an overall score ranging from 0 to 10. 14 The fixation objects are accommodative, and age appropriate, such as small stickers and videos for younger children and letters for older children and adults.
Levels 5 to 3 are assessed during a 30-second observation period. If exotropia is observed, testing stops and the control score is recorded as 5, 4, or 3 at that distance. If no exotropia is observed during the 30-second observation period, testing continues.
Levels 2 to 0 are then assessed and graded as the worst of three rapidly successive 10-second periods of occlusion. An occluder is first placed over the right eye for 10 seconds and the time required to re-fusion is noted. The left eye is then occluded for 10 seconds and the time to refusion is similarly measured. A third occlusion trial is performed on the eye that required the longest time to re-fuse. The worst of the three 10-second trials is recorded, resulting in a control score of 2, 1, or 0 at that distance.
If the patient has a micro-esotropia by simultaneous prism and cover test, but exodeviation by alternate cover test,25 the scale applies to the exodeviation.