Transposition of vertical recti for residual tropias

Transposition of vertical muscles for residual tropia was performed: nasal displacement for exotropia and temporal displacement for esotropia. Five millimeter equal displacement of superior and inferior recti corrected 10 to 14 prism diopter while equal displacement of 7 to 8 mm resulted in correction of 25 prism diopter. Special indications of this procedure may be: (1) residual tropia in cases with severe intractable ambylopia or pathology in one eye where patient and surgeon may be reluctant to operate on the sound eye, or (2) residual tropias of the alternating type in patients who underwent operations in all horizontal muscles of both eyes.