scholarly journals Version and vergence eye movements in optokinetic nystagmus induced by optic flow

10.1167/6.6.1 ◽  
2010 ◽  
Vol 6 (6) ◽  
pp. 1-1 ◽  
Author(s):  
D. Yang ◽  
M. Zhu ◽  
R. W. Hertle
Keyword(s):  
Eye Movements ◽  
Optic Flow ◽  
Optokinetic Nystagmus

Reversed Visual Motion and Self-Sustaining Eye Oscillations

Perception ◽  
1997 ◽  
Vol 26 (7) ◽  
pp. 823-830 ◽  
Author(s):  
Lothar Spillmann ◽  
Stuart Anstis ◽  
Anne Kurtenbach ◽  
Ian Howard
Keyword(s):  
Eye Movements ◽  
Flow Field ◽  
Negative Feedback ◽  
Positive Feedback ◽  
Optic Flow ◽  
Visual Motion ◽  
Optokinetic Nystagmus ◽  
Retinal Images ◽  
Wide Range ◽  
Reversed Motion

A random-dot field undergoing counterphase flicker paradoxically appears to move in the same direction as head and eye movements, ie opposite to the optic-flow field. The effect is robust and occurs over a wide range of flicker rates and pixel sizes. The phenomenon can be explained by reversed phi motion caused by apparent pixel movement between successive retinal images. The reversed motion provides a positive feedback control of the display, whereas under normal conditions retinal signals provide a negative feedback. This altered polarity invokes self-sustaining eye movements akin to involuntary optokinetic nystagmus.

Oculomotor Reactions in the Cuttlefish, Sepia Officinalis

1970 ◽  
Vol 52 (2) ◽  
pp. 369-384 ◽  
Author(s):  
H. COLLEWIJN
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Eye Position ◽  
Sepia Officinalis ◽  
Search Coil ◽  
Passive Rotation ◽  
Eye Velocity ◽  
Search Coil Technique ◽  
Better Than

1. Eye position in Sepia was measured in restrained animals, using a scleral search coil technique. 2. Optokinetic nystagmus was elicited by drum rotations from 0.035 up to 35°/sec. 3. Passive rotation of Sepia in darkness evoked a transient nystagmus, followed by after-nystagmus at arrest. 4. Combination of these two stimuli yielded the best results, but the ratio eye velocity/surroundings velocity was usually not better than 0.5. 5. Eye movements were conjugate and a closed eye could be driven by a seeing eye. Monocular reactions were smaller than binocular ones, but equal in both directions. 6. Fixation movements could not be demonstrated in the present conditions.

Establishing an Objective Measurement of Visual Acuity with a Computerised Optokinetic Nystagmus Suppression Test

2020 ◽  
Vol 237 (04) ◽  
pp. 502-505
Author(s):  
Noemie Schwob ◽  
Anja Palmowski-Wolfe
Keyword(s):  
Visual Acuity ◽  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Objective Measurement ◽  
Mean Difference ◽  
Alternative Option ◽  
Snellen Acuity ◽  
Suppression Test ◽  
Infrared Cameras ◽  
Acuity Test

Abstract Objective Investigating the correlation between subjective and objective VA (visual acuity) elicited with a newly developed computerised optokinetic nystagmus (OKN) suppression test (“SpeedWheel”) in adults. Methods SpeedWheel presented alternating black/white stripes moving horizontally across a LED screen. Seven VA steps were induced with Bangerter filters placed onto spectacle frames. Magnified eye movements were projected from infrared cameras inside the frames and displayed onto a smartphone. Dots whose size increased in logarithmic steps were superimposed to suppress OKN. Suppression of OKN resulted in the SpeedWheel acuity which was then correlated to Snellen acuity as measured with the Freiburg Acuity test. Results 28 eyes from 14 individuals were tested. FrACT-E correlated well to SpeedWheel (r: 0.89; p < 0.001). Snellen acuity was never lower than 0.14 LogMAR of SpeedWheel values. Bangerter filters showed greater mean difference to both methods indicating that this filter is not as predictable as suggested by the filter value. Conclusion SpeedWheel offers a fast (< 80 sec) and reliable alternative option to measure objective VA.

Optokinetic Eye Movements Elicited by Radial Optic Flow in the Macaque Monkey

1998 ◽  
Vol 79 (3) ◽  
pp. 1461-1480 ◽  
Author(s):  
Markus Lappe ◽  
Martin Pekel ◽  
Klaus-Peter Hoffmann
Keyword(s):  
Eye Movements ◽  
Flow Field ◽  
Eye Movement ◽  
Optic Flow ◽  
Macaque Monkey ◽  
Flow Fields ◽  
Movement Direction ◽  
Slow Phase ◽  
Eye Position ◽  
Self Motion

Lappe, Markus, Martin Pekel, and Klaus-Peter Hoffmann. Optokinetic eye movements elicited by radial optic flow in the macaque monkey. J. Neurophysiol. 79: 1461–1480, 1998. We recorded spontaneous eye movements elicited by radial optic flow in three macaque monkeys using the scleral search coil technique. Computer-generated stimuli simulated forward or backward motion of the monkey with respect to a number of small illuminated dots arranged on a virtual ground plane. We wanted to see whether optokinetic eye movements are induced by radial optic flow stimuli that simulate self-movement, quantify their parameters, and consider their effects on the processing of optic flow. A regular pattern of interchanging fast and slow eye movements with a frequency of 2 Hz was observed. When we shifted the horizontal position of the focus of expansion (FOE) during simulated forward motion (expansional optic flow), median horizontal eye position also shifted in the same direction but only by a smaller amount; for simulated backward motion (contractional optic flow), median eye position shifted in the opposite direction. We relate this to a change in Schlagfeld typically observed in optokinetic nystagmus. Direction and speed of slow phase eye movements were compared with the local flow field motion in gaze direction (the foveal flow). Eye movement direction matched well the foveal motion. Small systematic deviations could be attributed to an integration of the global motion pattern. Eye speed on average did not match foveal stimulus speed, as the median gain was only ∼0.5–0.6. The gain was always lower for expanding than for contracting stimuli. We analyzed the time course of the eye movement immediately after each saccade. We found remarkable differences in the initial development of gain and directional following for expansion and contraction. For expansion, directional following and gain were initially poor and strongly influenced by the ongoing eye movement before the saccade. This was not the case for contraction. These differences also can be linked to properties of the optokinetic system. We conclude that optokinetic eye movements can be elicited by radial optic flow fields simulating self-motion. These eye movements are linked to the parafoveal flow field, i.e., the motion in the direction of gaze. In the retinal projection of the optic flow, such eye movements superimpose retinal slip. This results in complex retinal motion patterns, especially because the gain of the eye movement is small and variable. This observation has special relevance for mechanisms that determine self-motion from retinal flow fields. It is necessary to consider the influence of eye movements in optic flow analysis, but our results suggest that direction and speed of an eye movement should be treated differently.

Optokinetic nystagmus in patients with SCA

Neurology ◽  
2018 ◽  
Vol 91 (13) ◽  
pp. e1255-e1261 ◽  
Author(s):  
Doniparthi V. Seshagiri ◽  
Pramod Kumar Pal ◽  
Sanjeev Jain ◽  
Ravi Yadav
Keyword(s):  
Eye Movements ◽  
Prospective Observational Study ◽  
Rating Scale ◽  
Optokinetic Nystagmus ◽  
Neurologic Examination ◽  
Clinical Tool ◽  
Motor Disability ◽  
Tendon Reflexes ◽  
Sensitive Marker

ObjectiveTo characterize the clinical features in patients with spinocerebellar ataxia (SCA) type 1, SCA2, and SCA3 and to evaluate the oculomotor dysfunction by using optokinetic nystagmus (OKN) testing, which may be a sensitive marker.MethodsIn this prospective observational study, all patients underwent detailed neurologic examination with special emphasis on eye movements. OKN was evaluated with a tape. Disease severity was measured with the International Co-Operative Ataxia Rating Scale (ICARS).ResultsA total of 73 genetically confirmed patients were included, of whom 28, 30, and 15 patients were positive for SCA1, SCA2, and SCA3, respectively. Dystonia was more common in patients with SCA3 (46%), and absent ankle jerk was more common in those with SCA2 (21.4%). Brisk deep tendon reflexes were common in patients with SCA1 (46.6%), followed by patients with SCA3 (26.6%) and SCA2 (7.1%). Vertical OKN was impaired in all patients and absent in 86.6% of patients with SCA1, 96% of those with SCA2, and 80% of those with SCA3. Horizontal OKN was absent in 30% of patients with SCA1, 57% of patients with SCA2, and 33% of those with SCA3. Higher motor disability (posture and gait, kinetic functions [Motor Disability] subscore on the ICARS) was associated with higher oculomotor dysfunction measured by OKN-saccades impairment grading but not with the Ocular Disorder subscore of ICARS (ICARS-OD).ConclusionOKN-saccades are a better and sensitive bedside clinical tool to quantify oculomotor dysfunction in neurodegenerative ataxias. Its role needs to be tested further in presymptomatic carriers. The current ICARS-OD scale to grade oculomotor dysfunction in degenerative ataxias need to be modified.

The Detection and Analysis of Optic Flow by Crabs: from Eye Movements to Electrophysiology

2002 ◽  
pp. 468-485 ◽  
Author(s):  
W. Jon. P. Barnes ◽  
B. Geoff. Horseman ◽  
Martin W. S. Macauley
Keyword(s):  
Eye Movements ◽  
Optic Flow

Lesions of the posterior commissure disable the vertical neural integrator of the primate oculomotor system

1994 ◽  
Vol 71 (6) ◽  
pp. 2582-2585 ◽  
Author(s):  
A. M. Partsalis ◽  
S. M. Highstein ◽  
A. K. Moschovakis
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Head Rotation ◽  
Oculomotor System ◽  
Squirrel Monkeys ◽  
Neural Integrator ◽  
Posterior Commissure ◽  
Oculomotor Neurons ◽  
Before And After ◽  
Gain Reduction

1. Spontaneous saccades, vestibuloocular responses (VOR), and optokinetic nystagmus were recorded in three squirrel monkeys before and after chemical or electrolytic lesion of the posterior commissure (PC). 2. PC lesions produced abnormal vertical eye movements, in particular, 1) Postsaccadic drifts, and 2) VOR gain reduction and phase advance more pronounced at lower frequencies of sinusoidal head rotation. Horizontal eye movements were much less affected (or normal). 3. We conclude that PC fibers are necessary for conveying the output of the vertical neural integrator to vertical oculomotor-neurons.

Short-Latency Vergence Eye Movements Induced by Radial Optic Flow in Humans: Dependence on Ambient Vergence Level

1999 ◽  
Vol 81 (2) ◽  
pp. 945-949 ◽  
Author(s):  
D.-S. Yang ◽  
E. J. Fitzgibbon ◽  
F. A. Miles
Keyword(s):  
Eye Movements ◽  
Optic Flow ◽  
Radial Flow ◽  
Human Subjects ◽  
Short Latency ◽  
Viewing Distance ◽  
Focus Of Expansion ◽  
Random Dot Patterns

Yang, D.-S., E. J. Fitzgibbon, and F. A. Miles. Short-latency vergence eye movements induced by radial optic flow in humans: dependence on ambient vergence level. J. Neurophysiol. 81: 945–949, 1999. Radial patterns of optic flow, such as those experienced by moving observers who look in the direction of heading, evoke vergence eye movements at short latency. We have investigated the dependence of these responses on the ambient vergence level. Human subjects faced a large tangent screen onto which two identical random-dot patterns were back-projected. A system of crossed polarizers ensured that each eye saw only one of the patterns, with mirror galvanometers to control the horizontal positions of the images and hence the vergence angle between the two eyes. After converging the subject's eyes at one of several distances ranging from 16.7 cm to infinity, both patterns were replaced with new ones (using a system of shutters and two additional projectors) so as to simulate the radial flow associated with a sudden 4% change in viewing distance with the focus of expansion/contraction imaged in or very near both foveas. Radial-flow steps induced transient vergence at latencies of 80–100 ms, expansions causing increases in convergence and contractions the converse. Based on the change in vergence 90–140 ms after the onset of the steps, responses were proportional to the preexisting vergence angle (and hence would be expected to be inversely proportional to viewing distance under normal conditions). We suggest that this property assists the observer who wants to fixate ahead while passing through a visually cluttered area (e.g., a forest) and so wants to avoid making vergence responses to the optic flow created by the nearby objects in the periphery.

Eye Movements in Cerebellar and Combined Cerebellobrainstem Diseases

1983 ◽  
Vol 92 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Carsten Wennmo ◽  
Bengt Hindfelt ◽  
Ilmari Pyykkö
Keyword(s):  
Quantitative Analysis ◽  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Optokinetic Nystagmus ◽  
Vestibular Nystagmus ◽  
Full Field ◽  
Eye Velocity ◽  
Voluntary Saccades ◽  
Cerebellar Disorders

We report a quantitative analysis of eye movement disturbances in patients with isolated cerebellar disorders and patients with cerebellar disorders and concomitant brainstem involvement. The most characteristic abnormalities in the exclusively cerebellar patients were increased velocities of the slow phases of vestibular nystagmus induced by rotation in the dark and increased peak velocities of the fast phases of optokinetic nystagmus induced by full-field optokinetic stimuli. Dysmetria of saccades was found in three of six cerebellar patients and gaze nystagmus in all six patients. The typical findings in the combined cerebellobrainstem group were reduced peak velocities of voluntary saccades, defective smooth pursuit and reduced peak velocities of the fast component of nystagmus during rotation in both the dark and light. All patients with combined cerebellobrainstem disorder had dysmetric voluntary saccades and gaze nystagmus. The numbers of superimposed saccades during smooth pursuit were uniformly increased. Release of inhibition in cerebellar disorders may explain the hyperresponsiveness and inaccuracy of eye movements found in this study. In addition, when lesions also involve the brainstem, however, integrative centers coding eye velocity are affected, leading to slow and inaccurate eye movements. These features elicited clinically may be useful in the diagnosis of cerebellar and brainstem disorders.

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