Binocular and monocular measurements of subjective visual vertical in vestibular loss

The objective of this study was to investigate the possibility to omit the time-consuming monocular vision measurement in the subjective visual vertical (SVV) test by demonstrating that there is no difference in the results between binocular and monocular measurements. Thirty-one patients with unilateral vestibular schwannoma and 20 normal subjects as controls were involved. Both binocular and monocular measurements of SVV were performed. The main outcome of this study was the difference in the results of SVV between binocular and monocular measurements. There were no significant differences in the tilts of the SVV between binocular and monocular measurements in vestibular schwannoma patients as well as in the controls. Abnormal tilts of SVV may be evaluated precisely only by binocular vision instead of monocular vision.