PURPOSE. We evaluated the roles of luminance and fixation in the pathophysiology of dissociated vertical divergence (DVD). METHODS. Vertical eye position was measured in 6 subjects with DVD (ages 11–47 years, 5 females) and 6 controls (ages 16–40 years, 5 females) using video-oculography (VOG) under conditions of change in fixation and luminance. RESULTS. Subjects with DVD showed the following VOG responses. When fixation was precluded with a translucent filter and bright light was shone into one eye to produce a marked binocular luminance disparity, we found some subjects had a small induced vertical divergence causing the illuminated eye to be lower than the nonilluminated eye (mean 1.68 6 1.58, P ¼ 0.06 compared to no vertical divergence using the signed rank test). When fixation was precluded with a translucent filter, while alternate occlusion produced a mild binocular luminance disparity, we found a smaller vertical divergence of the eyes that was not statistically significant (1.28 6 2.18, P ¼ 0.3). When alternate occlusion produced reversal of monocular fixation in the dark (with essentially no change in peripheral luminance disparity), there was a significant vertical divergence movement causing the covered eye to be relatively higher than the uncovered eye (7.28 6 3.18, P ¼ 0.03). The amplitude of this vertical divergence was similar to that measured under conditions of alternate occlusion in a lighted room (where there also was a significant average relative upward movement of the covered eye of 8.18 6 2.98, P ¼ 0.03). Control subjects showed no vertical divergence under any testing conditions. CONCLUSIONS. Dissociated vertical divergence is mediated primarily by changes in fixation and only to a minor degree by binocular luminance disparity.
- Dissociated vertical divergence
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience