Outcomes from surgical treatment for dissociated horizontal deviation

Long-term treatment results and recommendations for dissociated horizontal deviation (DHD) are sparse in the literature. We report the results of surgery for DHD with a mean of 48 months postsurgical follow-up.

Records were reviewed for 33 consecutive patients who underwent surgery to correct DHD between 1991 and 1997. Patient data were recorded, including age at time of DHD operation, initial diagnosis, history of prior surgery, number of operations related to DHD, amount of preoperative DHD for each operation, presence of concomitant esotropia or exotropia (XT), presence of amblyopia, type of operation performed, time interval between operations, and final alignment.

Twenty-five patients (78%) underwent a single operation for DHD. Seven patients (22%) underwent 2 operations, and 2 of those 7 patients (6% of the total) underwent 3 operations to control DHD and/or horizontal strabismus accompanying the DHD. Most patients (75%) had a prior history of congenital esotropia, which had been previously corrected with bilateral medial rectus muscle recession. Patients with an XT and DHD required bilateral surgery more frequently to control their deviation.

When DHD is prominent and manifests frequently, a surgical plan specific to the horizontal drift of the eyes is needed. Unilateral lateral rectus muscle recession appears to be adequate to control manifest DHD over time in most patients. Bilateral surgery will be needed occasionally for bilateral DHD when alternate fixation is present and frequently when XT and DHD coexist.