Drift of visually induced optostatic torsion.
OBJECTIVE
Compensatory ocular torsion has been found in response to static tilted visual stimuli. The purpose was to investigate if visually induced ocular torsion is maintained during continuous stimulation and to reinvestigate the effect of stimuli tilt angle.


METHODS
Eye movements were recorded in 19 healthy individuals using a 3-D video oculography system. One visual stimulus was used in the tests, a photographic image of a city scene with spatial clues relevant for body posture. The scenes were tilted counterclockwise around a central pivot point from 0 to 15 degrees (test A), from 0 to 30 degrees (test B), and from 0 to 45 degrees (test C). Each tilted stimulus position was held static for 4 min, 40 sec.


RESULTS
A compensatory torsional response was found in all subjects and test conditions. No significant difference was found between the different stimuli tilt angles. The torsional response was not maintained but drifted back towards the reference position.


CONCLUSIONS
Visually induced ocular torsion in response to a static tilted scene is not maintained, but drifts back towards the initial reference position. Higher cognitive functions such as imagination and attention certainly have an influence on the outcome.
Sverkersten
Ulrika
U
Department of Clinical Neuroscience, Division for Ophthalmology and Vision, Karolinska Institutet, Stockholm, Sweden. ulrika.sverkersten@ste.ki.se
Ygge
Jan
J
Pansell
Tony
T
D000222:Adaptation, Physiological; D000328:Adult; D005133:Eye Movements; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods*; D054159:Torsion, Mechanical; D055815:Young Adult