Asymmetric inferior oblique anterior transposition for incomitant asymmetric dissociated vertical deviation

Inferior oblique anterior transposition (IOAT) is indicated in patients with incomitant dissociated vertical deviation (DVD) larger in adduction. In general, bilateral surgery is recommended in patients with DVD unless there is deep monocular amblyopia. The purpose of this study is to evaluate the results of asymmetric IOAT in patients with asymmetric incomitant DVD larger in adduction.

Retrospective chart review of the records of all patients with incomitant asymmetric DVD associated with inferior oblique (IO) overaction who underwent asymmetric IO weakening procedure. In all patients, the eye with more DVD in adduction underwent IOAT to the temporal corner of the insertion of the inferior rectus (IR) muscle, and the eye with less DVD underwent IOAT to a position 3-4 mm posterior to the insertion of the IR. No other muscles were operated simultaneously. No patient had previous surgery on any cyclovertical extracular muscle.

Fourteen patients were included. Mean age at surgery was 10.3 ± 8.8 years (range 4-33). Primary position DVD preoperatively was 18 ± 2 PD in the eye with the larger DVD compared to 1.1 ± 1.0 PD postoperatively (p < 0.0001). DVD asymmetry between the lateral gaze with the largest DVD and the lateral gaze with the smallest DVD was 9.8 ± 3.1 PD (range 5-14 PD) preoperatively vs 1.1 ± 1.0 PD (range 0-2 PD), (p < 0.0001). Ten patients had preoperative V-pattern >10 PD (24.7 ± 8.7 PD, range 12-50 PD) preoperatively vs no patients postoperatively (mean V-pattern 4.4 ± 2.0 PD), (p < 0.0001). Postoperative follow up was 1.6 ± 0.7 years (range 1-3 years).

In patients with asymmetric incomitant DVD, asymmetric IOAT improves lateral incomitance without increasing the risk of antielevation, limitation in upgaze rotation, or hypertropia, or worsening the DVD in the eye with less deviation preoperatively.