Fixation switch: an unusual cause for adolescent and adult onset diplopia.

Sudden diplopia for adolescent and adult patients having childhood onset strabismus is an unusual occurrence. Recently, I examined three patients with a long history of strabismus and recent onset diplopia. All three patients acquired diplopia as a result of switching fixation from their normally preferred to their normally nonpreferred eye. Clinicians confronted with adolescent and/or adult patients having a long history of strabismus as well as a recent onset diplopia should consider a change in fixation as a possible mechanism.