HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Suzuki, Y. Articles by Ifukube, T. Search for Related Content PubMed PubMed Citation Articles by Suzuki, Y. Articles by Ifukube, T.

Effects of a Fixation Target on Torsional Optokinetic Nystagmus

¹ From the Departments of Physiology and ² Ophthalmology, School of Medicine, Hokkaido University; and ³ Laboratory of Sensory Information Engineering, Research Institute for Electronic Science, Sapporo, Japan.

PURPOSE. To investigate the effects of an imaginary and a visual target on torsional optokinetic nystagmus (tOKN) and directional symmetry of tOKN.

METHODS. Torsional OKN was induced by a rotating random dot pattern (52° in diameter, constant angular velocity: ±30 deg/sec to ±52 deg/sec) with an imaginary or a visual target in 11 eyes of 10 healthy humans by dual-search coil methods.

RESULTS. Intorsional OKN and extorsional OKN were symmetrical in their slow-phase gain. The mean slow-phase gain (0.037/0.041, intorsion/extorsion) of tOKN during fixation on a visual target at the center of the rotating random dot pattern was significantly (P < 0.002) smaller than that (0.051/0.052, intorsion/extorsion) during fixation on an imaginary target at the center of the rotating random dot pattern. The mean tOKN slow-phase beat duration (840 msec/724 msec, intorsion/extorsion) during fixation on the visual target was significantly (P < 0.002) longer than that (585 msec/543 msec, intorsion/extorsion) during fixation on the imaginary target. In seven eyes of six subjects, the mean slow-phase gain and beat duration (0.034 and 812 msec) of tOKN during fixation on a visual target 6.5° left or right from the center of the rotating random dot pattern were not significantly different from those (0.037 and 825 msec) with a visual target at the center of the rotating random dot pattern (P > 0.3).

CONCLUSIONS. A visual target spot suppresses tOKN by a nonpursuit visual system. Intorsional and extorsional OKNs were symmetrical.

This article has been cited by other articles:

				N. Washio, Y. Suzuki, M. Sawa, and K. Ohtsuka Gain of Human Torsional Optokinetic Nystagmus Depends on Horizontal Disparity Invest. Ophthalmol. Vis. Sci., January 1, 2005; 46(1): 133 - 136. [Abstract] [Full Text] [PDF]

				S J Farooq, F A Proudlock, and I Gottlob Torsional optokinetic nystagmus: normal response characteristics Br. J. Ophthalmol., June 1, 2004; 88(6): 796 - 802. [Abstract] [Full Text] [PDF]

				M Sehi and J G Flanagan The effect of image alignment on capillary blood flow measurement of the neuroretinal rim using the Heidelberg retina flowmeter Br. J. Ophthalmol., February 1, 2004; 88(2): 204 - 206. [Abstract] [Full Text] [PDF]

				K. V. Thilo, A. Kleinschmidt, and M. A. Gresty Perception of Self-Motion From Peripheral Optokinetic Stimulation Suppresses Visual Evoked Responses to Central Stimuli J Neurophysiol, August 1, 2003; 90(2): 723 - 730. [Abstract] [Full Text] [PDF]