Related Experiment Video
Updated: May 25, 2026

Using Eye-tracking to Assess the Relative Importance of Visual and Vestibular Input to Subcortical Motion Processing in the Roll Plane
Published on: August 22, 2025
Ocular torsions and the subjective visual vertical with central vestibulo-ocular system lesions: independence
1Neuro-Ophthalmology Unit, Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Sweden. lars.frisen@neuro.gu.se
Objectives:
Torsions of the eyes and deviations of the subjective visual vertical in roll occur regularly with disorders of the central vestibulo-ocular system. Although nearly universally coexisting, torsions and deviation have been held to be more or less independent of each other.
Materials And Methods:
Angles of torsion were determined from fundus photographs in 55 subjects representing a variety of acute, focal, brainstem or cerebellar lesions. Measured torsions were contrasted with quantitative measurements of the subjective visual vertical.
Results:
Torsions and deviations proved to be directly proportional, with a direction coefficient close to unity, and were strongly correlated (r = 0.86).
Conclusions:
Torsions and deviations are strongly dependent. This result should allow the generation of a more transparent pathophysiological model. From a practical point of view, measurements of deviation appeared more robust than those of torsion.
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