Ocular torsions and the subjective visual vertical with central vestibulo-ocular system lesions: independence disproved.
OBJECTIVE
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.


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.
Neuro-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
L
L
Frisén
D000328:Adult; D000368:Aged; D001927:Brain Diseases / Q000473:pathology* / Q000503:physiopathology*; D001933:Brain Stem / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D013223:Statistics as Topic; D014796:Visual Perception / Q000502:physiology*