Evaluation of Exotropia After Patching the Eye or After Prism Adaptation

Inclusion Criteria: * Diagnosed with divergence excess exotropia according to standard criteria (see Study Procedures for specifics) * No prior strabismus surgery * Able to cooperate with testing (by examiner determination) * Neurologically normal except for strabismus (ADHD and autism spectrum are not exclusion criteria as long as the subject can cooperate for necessary testing) * Not amblyopic at the time of enrollment (best-corrected visual acuity in both eyes of 20/40 or better) * Under 18 years of age. There is no lower age limit as long as the subject can cooperate for the required testing. * No diagnosis of dissociated vertical deviation Exclusion Criteria: * No diagnosis of divergence excess exotropia according to standard criteria (see Study Procedures for specifics) * Prior strabismus surgery * Unable to cooperate with testing (by examiner determination) * Diagnosed with a neurological disorder (ADHD and autism spectrum are not exclusion criteria as long as the subject can cooperate for necessary testing) * Best-corrected visual acuity in either eye worse than 20/40 * 18 years of age or older * Diagnosed with dissociated vertical deviation