After strabismus surgery, diplopia can occur in a small number of patients, but in most patients it disappears on its own within a short period of time, as early as one to several weeks after surgery. Children have a rapid change in binocular vision and overcome diplopia faster than adults. Postoperative diplopia should be thoroughly explained in adults with strabismus. The amount of correction for this type of strabismus should be such that it does not interfere with daily life. Postoperative diplopia can also occur if the surgery is overcorrected, such as when an exotropia becomes an internal strabismus after surgery, or an internal strabismus becomes an exotropia after surgery. Mild diplopia does not need to be treated and is corrected with trigeminal lenses if necessary, and can be corrected surgically again when there is intolerable diplopia in the frontal area.