Combined resection and anterior transposition of the inferior oblique muscle for asymmetric double dissociated vertical deviation

Objective: To evaluate the efficacy of combined monocular resection and bilateral anterior transposition of the inferior oblique (IO) muscle for asymmetric double dissociated vertical deviation (DVD). Design: Nonrandomized, comparative clinical trial. Participants: Twelve patients with asymmetric DVD and coexisting unequal IO overaction (IOOA). Intervention: Six consecutive patients underwent combined graded monocular resection and bilateral anterior transposition of the IO muscle and six consecutive historical control patients underwent equal anteriorization of the IO muscle. Main Outcome Measures: Between-group comparison of the postoperative vertical deviation and reduction in IOOA. Results: The mean difference of the asymmetric DVD in the primary position was reduced from 13.3 ± 4.8 prism diopters (PD) to 2.2 ± 1.8 PD in the study group (P = 0.001) and from 13.3 ± 4.0 PD to 10.2 ± 3.1 PD in the control group (P = 0.003). The difference in improvement between the groups was statistically significant (P = 0.004). The IOOA was significantly reduced in both groups. Conclusions: Bilateral IO anteriorization with monocular-graded IO resection should be considered as the treatment of choice in patients with asymmetric DVD with IOOA.