With the exception of individual children who exhibit constant exotropia from birth, most children exhibit progressive exotropia. Initially, there is intermittent exotropia when the child is looking at the distance outdoors, when the child closes one eye in bright light; further, there is intermittent exotropia when the child is looking at the near; if there is constant exotropia when looking at the distance or constant exotropia when looking at the near, it means that the strabismus causes complete destruction of the visual function of both eyes, which means that the brain cannot control both eyes completely. The aim is to preserve the brain’s ability to control both eyes as much as possible. The goal is to preserve as much of the brain’s ability to control both eyes as possible, because this ability cannot be restored after complete loss. How I determine the need for surgery in children with outpatient exotropia 1. First of all, they need to have normal corrected vision. In particular, the progression of exotropia in many children is related to myopia. Such children need to bring enough corrective myopic lenses to properly measure the strabismus. A small percentage of children with amblyopia also require masking to treat the amblyopia before surgery. 2, masking de-masking test is the most important basis. I will ask the child to look at a distant visual marker, cover either eye for a few seconds, then remove the cover and observe how long it takes for the uncovered eye to return to its proper position. If it takes 5 seconds or more to return, or even if it remains exotropic after 1 minute, then I would recommend surgery.