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Updated: May 11, 2026
Recording Horizontal Saccade Performances Accurately in Neurological Patients Using Electro-oculogram
Published on: March 13, 2018
Simultaneous recordings of ocular microtremor and microsaccades with a piezoelectric sensor and a video-oculography
Michael B McCamy1,2, Niamh Collins3, Jorge Otero-Millan1,4
1Department of Neurobiology, Barrow Neurological Institute, USA.
Abstract:
Our eyes are in continuous motion. Even when we attempt to fix our gaze, we produce so called "fixational eye movements", which include microsaccades, drift, and ocular microtremor (OMT). Microsaccades, the largest and fastest type of fixational eye movement, shift the retinal image from several dozen to several hundred photoreceptors and have equivalent physical characteristics to saccades, only on a smaller scale (Martinez-Conde, Otero-Millan & Macknik, 2013). OMT occurs simultaneously with drift and is the smallest of the fixational eye movements (∼1 photoreceptor width, >0.5 arcmin), with dominant frequencies ranging from 70 Hz to 103 Hz (Martinez-Conde, Macknik & Hubel, 2004). Due to OMT's small amplitude and high frequency, the most accurate and stringent way to record it is the piezoelectric transduction method. Thus, OMT studies are far rarer than those focusing on microsaccades or drift. Here we conducted simultaneous recordings of OMT and microsaccades with a piezoelectric device and a commercial infrared video tracking system. We set out to determine whether OMT could help to restore perceptually faded targets during attempted fixation, and we also wondered whether the piezoelectric sensor could affect the characteristics of microsaccades. Our results showed that microsaccades, but not OMT, counteracted perceptual fading. We moreover found that the piezoelectric sensor affected microsaccades in a complex way, and that the oculomotor system adjusted to the stress brought on by the sensor by adjusting the magnitudes of microsaccades.
Insights
Microsaccades, not ocular microtremor (OMT), prevent visual fading during attempted fixation. Piezoelectric sensors, used to measure OMT, altered microsaccade characteristics, prompting oculomotor system adjustments.
Area of Science:
- Neuroscience
- Ophthalmology
- Visual Perception
Background:
- Fixational eye movements, including microsaccades and ocular microtremor (OMT), occur even during attempted visual fixation.
- Ocular microtremor (OMT) is characterized by high frequencies and small amplitudes, making piezoelectric transduction the most accurate recording method.
- Studies on OMT are less common than those on microsaccades due to measurement challenges.
Purpose of the Study:
- To investigate the role of OMT in counteracting perceptual fading during fixation.
- To examine the influence of piezoelectric sensors on microsaccade characteristics.
Main Methods:
- Simultaneous recording of OMT and microsaccades using a piezoelectric device and infrared video tracking.
- Analysis of the impact of OMT and microsaccades on perceptual fading.
- Assessment of changes in microsaccade properties due to the presence of a piezoelectric sensor.
Main Results:
- Microsaccades, but not OMT, were found to counteract perceptual fading of visual targets.
- The piezoelectric sensor significantly affected microsaccade characteristics in a complex manner.
- The oculomotor system demonstrated adaptive adjustments in microsaccade magnitudes in response to sensor-induced stress.
Conclusions:
- Microsaccades play a crucial role in maintaining visual awareness during fixation by preventing perceptual fading.
- The use of piezoelectric sensors for OMT measurement can introduce artifacts and alter microsaccade behavior.
- Further research is needed to understand the adaptive mechanisms of the oculomotor system when using specialized recording equipment.
