A surgical alternative for dissociated vertical deviation based on new pathologic concepts: weakening all four oblique eye muscles. Outcome and results in 9 cases.

PURPOSE: To test new and recent theories on the etiology of Dissociated Vertical Deviation (DVD) with an appropriate new alternative surgical technique.
METHOD: Nine patients were prospectively selected. The surgical technique used was simultaneous and symmetrical weakening of all 4 oblique eye muscles in order to reduce bilateral cyclotorsion. For analysis, "Statistical Significance" level used was p<0.05.
RESULTS: Mean preoperative hypertropia was 17.9 prism diopters (pd) for the right eyes (RE) and 17.7 pd for the left eyes (LE). Mean post-surgical deviation achieved was 6.44 pd for the REs and 5.78 pd for the LEs. Statistical analysis (Wilcoxon's Test) showed a p<0.02 for both eyes. In all cases, a symmetrical correction was also obtained.
CONCLUSIONS: The hypothesis that the manifest hypertropia seen in patients with DVD is secondary to cyclotorsion, mediated primarily by the oblique muscles, was validated by improving (reducing) the DVD by performing bilateral and symmetrical weakening of all four oblique extraocular muscles.