Optokinetic Nystagmus Eye Movements Research Articles

An Effective Algorithm to Analyze the Optokinetic Nystagmus Waveforms from a Low-Cost Eye Tracker.

Objective: Most neurological diseases are usually accompanied by changes in the oculomotor nerve. Analysis of different types of eye movements will help provide important information in ophthalmology, neurology, and psychology. At present, many scholars use optokinetic nystagmus (OKN) to study the physiological phenomenon of eye movement. OKN is an involuntary eye movement induced by a large moving surrounding visual field. It consists of a slow pursuing eye movement, called “slow phase” (SP), and a fast re-fixating saccade eye movement, called “fast phase” (FP). Non-invasive video-oculography has been used increasingly in eye movement research. However, research-grade eye trackers are often expensive and less accessible to most researchers. Using a low-cost eye tracker to quantitatively measure OKN eye movement will facilitate the general application of eye movement research. Methods & Results: We design an analytical algorithm to quantitatively measure OKN eye movements on a low-cost eye tracker. Using simple conditional filtering, accurate FP positions can be obtained quickly. The high-precision FP recognition rate is of great help for the subsequent calculation of eye movement analysis parameters, such as mean slow phase velocity (MSPV), which is beneficial as a reference index for patients with strabismus and other eye diseases. Conclusions: Experimental results indicate that the proposed method achieves faster and better results than other approaches, and can provide an effective algorithm to calculate and analyze the FP position of OKN waveforms.

A Fast and Effective System for Analysis of Optokinetic Waveforms with a Low-Cost Eye Tracking Device.

Optokinetic nystagmus (OKN) is an involuntary eye movement induced by motion of a large proportion of the visual field. It consists of a “slow phase (SP)” with eye movements in the same direction as the movement of the pattern and a “fast phase (FP)” with saccadic eye movements in the opposite direction. Study of OKN can reveal valuable information in ophthalmology, neurology and psychology. However, the current commercially available high-resolution and research-grade eye tracker is usually expensive. Methods & Results: We developed a novel fast and effective system combined with a low-cost eye tracking device to accurately quantitatively measure OKN eye movement. Conclusions: The experimental results indicate that the proposed method achieves fast and promising results in comparisons with several traditional approaches.

Alternating optokinetic nystagmus (OKN) induced by intermittent display of stationary gratings

In this paper, we report a novel optokinetic nystagmus (OKN), which was evoked by stationary gratings presented intermittently. OKN eye movements were accurately measured by the electromagnetic scleral search-coil technique. For the luminance stimuli, alternating OKN was elicited when the interstimulus interval (ISI) ranged from 33 to 83 ms duration and the ISI luminance approximated to the mean luminance of the stimulus grating; for chromatic (red/green) stimuli, the OKN could be evoked in non-isoluminant condition and vanished in the isoluminant condition. It is a plausible explanation that the present OKN, intermittent display-of-gratings-induced OKN (IDG-OKN), might be related to the temporal impulse response of the luminance channel in vision.

Prediction of the sequence of optokinetic nystagmus eye movements reveals deterministic structure in reflexive oculomotor behavior.

Optokinetic nystagmus (OKN) is a reflexive eye movement with a characteristic pattern of alternating fast and slow phases (resembling a noisy sawtooth), but with significant variation in the timing and amplitude of its components. We attempt to predict the sequence of OKN fast and slow phases by embedding them in state space and forming local approximations to the resulting trajectories. There is significant predictability only in the sequence of fast phase starting and ending positions. This is presumably related to the desire of the oculomotor system to aim the eyes at a location in space where something important might be expected to appear, leading to a partially deterministic rule for generating the end points of the fast phases.