Figure 3.

Video-oculographic recording from a subject during haploscopic cover testing. Initially, the induced right-over-left vertical deviation is slowly decaying during left eye (only) viewing. Then, as the right eye target is uncovered at approximately 8 seconds, a vertical fusional vergence occurs as the right eye moves upward to regain fusion of the presented right-over-left vertical disparity, while the left eye continues fixing. This vertical vergence movement is accompanied by a clockwise cycloversion. Vertical vergence (thick black trace) is shown, with positive representing the right eye higher than the left. Upward deflections of right eye torsion (thin black trace) and of left eye torsion (thin gray trace) represent clockwise eye movements from the subject's perspective looking forward (extorsion of the right eye and intorsion of the left eye). LEV, left eye vertical; REV, right eye vertical; LET, left eye torsion; RET, right eye torsion.