Measuring mental workload: ocular astigmatism aberration as a novel objective index

Area of Science:

• Ophthalmology
• Cognitive Neuroscience
• Human Factors Engineering

Background:

• Assessing mental workload is crucial for understanding human performance and safety.
• Current methods for measuring mental workload can be subjective or invasive.
• Ocular aberrations, changes in the eye's optical system, are sensitive to physiological changes.

Purpose of the Study:

• To investigate the relationship between mental task complexity and ocular aberrations.
• To determine if ocular astigmatism can serve as a reliable indicator of mental workload.
• To explore the potential of using ocular metrics for objective mental workload assessment.

Main Methods:

• Young adults performed two perceptually matched mental tasks with varying cognitive demands.
• Ocular aberrations were measured using a wavefront sensor.
• Total, internal, and corneal root mean square (RMS) aberrations were calculated for natural and scaled pupil sizes.

Main Results:

• Significant differences in ocular astigmatism RMS were observed between mental tasks, particularly with natural and 5mm pupils.
• Pupil size, intraocular pressure, perceived mental load, and cognitive performance were all influenced by mental complexity.
• Ocular astigmatism aberration showed sensitivity to the cumulative effect of mental effort.

Conclusions:

• Ocular astigmatism, influenced by intraocular pressure, shows potential as an objective index for evaluating cognitive processing.
• This finding suggests ocular astigmatism aberration could be a novel, reliable marker for assessing mental workload in practical settings.
• Further research may validate ocular astigmatism as a convenient tool for real-world mental workload assessment.