Unilateral inferior oblique anterior transposition for markedly asymmetric dissociated vertical deviation with unilateral inferior oblique over-action

BACKGROUND: To evaluate the results of unilateral inferior oblique anterior transposition (IOAT) for markedly asymmetric dissociated vertical deviation (DVD) combined with inferior oblique over-action (IOOA). METHODS: Retrospective chart review of the records of all patients with asymmetric DVD combined with unilateral IOOA in the non-dominant eye who received unilateral IOAT on the non-dominant eye. No other muscles were operated on simultaneously. The amount of DVD and IOOA were measured before and after the operation and statistically analysed. RESULTS: Seventeen patients were included. The mean age at surgery was 23.5 ± 8.4 (range 12–38) years old. The mean postoperative follow-up period was 15.7 ± 7.2 (range 6–32) months. The primary position DVD was 19.6 ± 5.4 (range 14–36) PD preoperatively and decreased significantly to 2.9 ± 2.0 (range 0–8) PD postoperatively (P < 0.01). Preoperatively, there were 2, 7, and 8 patients with + 1, + 2, and + 3 IOOA, respectively, and these were reduced from 2.4 ± 0.7 to 0.3 ± 0.4 postoperatively (P < 0.01). None of the patients were complicated obvious hypotropia, anti-elevation syndrome or IOOA in the contralateral eye. CONCLUSIONS: Unilateral IOAT was recommended in patients with asymmetric DVD coexists with unilateral IOOA.