[Microtropia - heterophoria].

In 31 cases of microtropia combined with large angle esophoria, prism treatment and surgery to eliminates the phoria component were performed. In 19 cases a stable microsotropia remained after elimination of the phoria component. In 12 cases unstable microtropia was found, i.e., the microtropia disappeared after treatment. In these cases, microtropia may be secondary to the heterophoria. The treatment of the esophoria component in cases of microtropia/esophoria with refraction or bifocal correction, prisms and surgery is as much indicated as in simple esophoria.