Orthoptic treatment of vertical deviations.

Four patients with large vertical deviations were treated with a combination of prismatic glasses and orthoptics. The least amount of prism which eliminated diplopia, followed by horizontal fusional range extension, was prescribed. After vergences were normalized the prism was further reduced by two prism diopters and horizontal fusional range extension was repeated. This process was repeated until either a plateau was achieved or the prism was eliminated. All four patients completed therapy with almost total alleviation of symptoms and elimination of full-time prismatic correction.