Skew transposition of vertical rectus muscles for excyclovertical deviation.

PURPOSE The authors established a surgical treatment for excyclovertical strabismus in which either the inferior rectus muscle or the superior rectus muscle was transposed diagonally. The effects and the safety of the procedure, called skew transposition, were studied. METHODS Eighteen operations using local anesthesia with eye drops were performed on 17 cases, including 10 with superior oblique palsy. Diplopia was checked during the operation with the cooperation of each patient. Both the clinical findings and eye deviation were examined during observation periods. RESULTS After the first operation, the diplopia in the primary position had disappeared in 10 cases and had improved in the other 7. The average effect of all operations on excyclodeviation was a correction of 6.2 degrees in the primary position. In the 7 cases of superior oblique palsy that received nasal recession of the inferior rectus muscle, the average correction of excyclodeviation was 6.4 degrees, and vertical deviation improved 1.8 degrees per 1 mm of recession. In no case did the diplopia worsen, nor were there any complications. CONCLUSIONS This safe procedure facilitates the simultaneous improvement of both excyclo- and vertical deviations. It may become the treatment of choice for excyclovertical strabismus.