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Kristina Irsch, David L Guyton, Nicholas A Ramey, Rohit S Adyanthaya, Howard S Ying
PURPOSE: To document the cyclovertical ocular motor mechanism used for vertical fusion in healthy subjects, and to explore whether vertical vergence training in healthy individuals can produce objectively confirmed vertical deviations that change with head tilt, revealing a basic mechanism that can produce a pattern of misalignment in an otherwise normal ocular motor system that is similar to superior oblique muscle paresis (SOP). METHODS: Seven subjects with normal orthoptic examinations were adapted to vertical image disparities using our tilting haploscopic eye-tracking apparatus presenting concentric circle targets without torsional cues...
May 2013: Investigative Ophthalmology & Visual Science
Itsaso Olasagasti, Christopher J Bockisch, David S Zee, Dominik Straumann
When humans are accelerated along the body vertical, the right and left eyes show oppositely directed torsional modulation (cyclovergence). The origin of this paradoxical response is unknown. We studied cyclovergence during linear sinusoidal vertical motion in healthy humans. A small head-fixed visual target minimized horizontal and vertical motion of the eyes and therefore isolated the torsional component. For stimuli between 1 and 2 Hz (near the natural range of head motion), the phase of cyclovergence with respect to inertial acceleration was 8...
July 6, 2011: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
L J Van Rijn, H J Simonsz, M P Tusscher
We studied the relation between vertical eye movements and binocular torsion in five subjects with dissociated vertical deviation (DVD). During trials, subject viewed a well illuminated Snellen letter chart, with both eyes uncovered during 4 seconds, Subsequently, DVD was induced by covering one eye during 4 seconds. Finally, both eyes were uncovered during 4 seconds. Several trials were recorded for each subject and covered eye. Eye movements were measured with scleral coils. We found that in all subjects, the vertical divergence followed an exponential course with a time constant of 0...
1997: Strabismus
I Olasagasti, C J Bockisch, D S Zee, D Straumann
We present results of a study of torsional eye movements evoked by earth-vertical accelerations along the subject's longitudinal axis. The earth-vertical stimulus leads to a gravito-inertial acceleration vector that changes magnitude but not direction. It can therefore be viewed as a dynamic change of the gravity level. Up-down oscillations induced relatively symmetric cyclovergence (0.6-2.2 degrees peak-to-peak). Eyes intorted/extorted for higher/lower effective gravity. The phase of this modulation was small relative to chair acceleration...
2008: Progress in Brain Research
Mark M J Houben, Janine Goumans, Johannes van der Steen
PURPOSE: This study compared the performance of a video-based infrared three-dimensional eye tracker device (Chronos) with the scleral search coil method. METHODS: Three-dimensional eye movements were measured simultaneously with both systems during fixation, saccades, optokinetic stimulation, and vestibular stimulation. RESULTS: Comparison of fixation positions between -15 degrees and +15 degrees showed that horizontal and vertical eye position signals of the two systems were highly correlated (R2 = 0...
January 2006: Investigative Ophthalmology & Visual Science
Andrea B Jehn, René M Muri, Daniel S Mojon
OBJECTIVE: To study the influence of cycloversions induced by head tilt on parameters of scanning laser polarimetry. METHODS: Five left and five right eyes of 9 normal subjects were measured in seven different head tilt positions by one examiner using a scanning laser polarimeter (Nerve Fiber Analyzer, NFA II, LDT Inc., San Diego, Calif., USA). Images were acquired for the following head tilt positions: upright, 10, 20, 30 degrees to the right, and 10, 20, 30 degrees to the left...
September 2003: Ophthalmologica. Journal International D'ophtalmologie
A Spielmann
Cyclotorsions are movements of cyclorotation of the eyes (in- or ex-cycloversions or vergences) and positions of cyclotorsion (in- or ex-cyclotorsion or cyclodeviation). Torsion is absent when the vertical meridian 0 traversing the cornea center is parallel to a plumbline. In a state of intorsion, the nasal end of the horizontal meridian is higher than the temporal part: the optic disk is lower than the fovea. Conversely the optic disk is higher in cases of excyclotorsion. Fundus observation is the only objective test in cases of torsion...
November 2002: Journal Français D'ophtalmologie
Michael C Brodsky
BACKGROUND: Primitive adaptations in lateral-eyed animals have programmed the oblique muscles to counterrotate the eyes during pitch and roll. In humans, these torsional movements are rudimentary. PURPOSE: To determine whether the human oblique muscles are vestigial. METHODS: Review of primitive oblique muscle adaptations and exaptations in human binocular vision. RESULTS: Primitive adaptations in human oblique muscle function produce rudimentary torsional eye movements that can be measured as cycloversion and cyclovergence under experimental conditions...
June 2002: Archives of Ophthalmology
Hermann D Schworm, Jan Ygge, Tony Pansell, Gunnar Lennerstrand
PURPOSE: According to recent literature, the presence and the amount of true compensatory ocular counterroll is still debatable. The purpose of the current study was to assess compensatory counterroll in response to lateral head tilt using a new noninvasive recording technique, and, furthermore, to find out whether the amount of counterroll is influenced by the presence or absence of spatial orientation. METHODS: Eye movement recordings were performed using the infrared three-dimensional video oculography (3D-VOG) technique...
March 2002: Investigative Ophthalmology & Visual Science
D L Guyton
PURPOSE: The etiology and mechanism of dissociated vertical deviation (DVD) are explored. METHODS: In 6 young adults with DVD, the simultaneous horizontal, vertical, and torsional eye movements for both eyes were recorded by using dual-coil scleral search coils. Analysis of the simultaneous vertical and torsional movements that occurred during the DVD response identified the primary muscles acting in the vergences and versions involved. RESULTS: Typically, both horizontal and cyclovertical latent nystagmus developed upon occlusion of either eye...
June 2000: Journal of AAPOS: the Official Publication of the American Association for Pediatric Ophthalmology and Strabismus
J Porrill, J P Ivins, J P Frisby
Two recently developed kinematic models of human eye movements predict systematic departures from Listing's law which are associated with changes in vergence. This vergence-dependent torsion t is proportional to elevation e and vergence v, that is t = kev/2. The proposed value for k is either 1 (Van Rijn, L. J., & Van den Berg, A. V. (1993). Vision Research, 33, 691-708) or 1/2 (Minken, A. W. H., Gielen, C. C. A. M., & Van Gisbergen, J. A. M. (1995). Vision Research, 35, 93-102). One implication of both models is that an eye with a constant fixation direction should exhibit systematic torsional variation during movements of the other eye...
November 1999: Vision Research
E W Cheeseman, D L Guyton
OBJECTIVES: To test the previous findings of Enright that disparity-induced vertical vergence is mediated primarily by the oblique muscles, and to relate this normal eye movement pattern to the eye movement pattern seen in subjects with dissociated vertical deviation. METHODS: Sixteen normal volunteers underwent 55 measurements of the cycloversion associated with prism-induced vertical vergence using an afterimage apparatus. A Vernier scale measured the direction and magnitude of the torsional shift that occurred with recovery of fusion on removal of a 3- or 4-prism diopter prism...
September 1999: Archives of Ophthalmology
D L Guyton, E W Cheeseman, F J Ellis, D Straumann, D S Zee
PURPOSE: Dissociated vertical deviation (DVD) has eluded explanation for more than a century. The purpose of this study has been to elucidate the etiology and mechanism of DVD. METHODS: Eye movement recordings of six young adults with DVD were made with dual-coil scleral search coils under various conditions of fixation, illumination, and head tilt. Horizontal, vertical, and torsional eye movements were recorded for both eyes simultaneously. Analyses of the simultaneous vertical and torsional movements occurring during the DVD response were used to separate and identify the component vergence and version eye movements involved...
1998: Transactions of the American Ophthalmological Society
J P Ivins, J Porrill, J P Frisby
Several categories of torsional eye movements obey Listing's law; however, systematic deviations from this law occur during vergence. Two kinematic models attempt to incorporate these deviations, both of which are supported by experimental evidence; however, they lead to different torsion predictions. These discrepancies have been explained in terms of experimental procedures, but it now seems likely from several recent studies that individual differences in torsion patterns may also be important. This study therefore examines the variation of torsion during a smooth asymmetric vergence task in which a fixation target was moved along the line-of-sight of the right eye at 15 degrees elevation; each of five subjects observed five trials of both inward and outward target motion, repeated in two sessions several weeks apart...
March 1999: Vision Research
A V van den Berg, L J van Rijn, J T de Faber
Recently, we developed a model of binocular fixation. This model predicts the amount of cyclovergence as a function of target elevation and horizontal target vergence. The prediction derives from the assumption that version and vergence add linearly and that the eye positions are constrained in three respects: (1) the foveae of the two eyes are directed towards the target, (2) the version component follows Listing's law, i.e. cycloversion, and horizontal and vertical version are not independent, (3) the vergence component is restricted to a plane approximately perpendicular to Listing's plane, i...
December 1995: Vision Research
L J Van Rijn, J Van der Steen, H Collewijn
We studied binocular cyclorotatory (torsional) eye movements in response to gratings that oscillated sinusoidally in a frontal plane. The square-wave gratings viewed by the right and left eye were presented and controlled separately to induce cycloversion and cyclovergence by oscillation in phase and out of phase. Eye movements were recorded with scleral induction coils. Stimulus oscillation frequency ranged from 0.125 to 1 Hz and the wavelength of the gratings ranged from 0.92 to 25.75 deg of visual angle...
February 1994: Vision Research
M Inoue, Y Kita
The horizontal, vertical and cyclorotational components of eye movements were analyzed in 8 cases of dissociated vertical deviation (DVD), using a Fundus Haploscope (Inatomi, 1980) and an Eye Movement Analyzing System (Kani, 1985). Excyclomovements and upward movements were observed in the deviating eyes in all cases, and incyclomovements in the fixating eyes in 6 cases. Sequential analysis revealed these movements to be "cycloversion". Vertical movements and cyclorotational movements were similar in their forms, but in some parts only the torsional movements were recognized...
November 1993: Nippon Ganka Gakkai Zasshi
L J Van Rijn, J Van der Steen, H Collewijn
We investigated spontaneous variation of binocular torsion. Variation was expressed as SD of torsional eye positions measured over periods up to 32 sec. Subjects viewed a single dot target for periods of 32 sec. In half of the trials a large random-dot background pattern was superimposed on the dot. The movements of both eyes were measured with scleral induction coils. Spontaneous torsional movements were largely conjugate: cyclovergence was much more stable than cycloversion. This difference was not due to roll head movements...
April 1994: Vision Research
L J Van Rijn, H Collewijn
Recently, Enright described an unexpected association between disparity-induced vertical vergence and cycloversion (conjugate eye torsion) [Enright (1992) Vision Research, 415, 279]. The present experiments were performed to verify these findings and investigate the nature of this association. We presented subjects with a dichoptic image of concentric circles in which a step in vertical disparity of 1 deg was introduced. After 4 sec the disparity was eliminated. Eye movements were measured with scleral coils...
September 1994: Vision Research
I P Howard, L Sun, X Shen
Rotation of a display in the frontal plane evokes a conjugate nystagmic rotation of the eyes (cycloversion) about the visual axes, with slow phases in the direction of stimulus motion--a response known as torsional optokinetic nystagmus (TOKN). Antiphase rotation of large dichoptic displays evokes a disconjugate rotation of the eyes about the visual axes, a response known as cyclovergence. Using the scleral-coil technique for monitoring eye movements we recorded TOKN evoked by black-and-white sectored displays rotating about the visual axis at an angular velocity of 30 degrees/s...
1994: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
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