Changes in the dark focus of accommodation associated with simulator sickness

Area of Science:

• Ophthalmology
• Neuroscience
• Human Factors

Background:

• Simulator sickness is a common issue in aviation and virtual environments.
• Dark focus of accommodation, the eye's resting focus point, is a potential indicator of autonomic nervous system activity.
• Understanding the link between dark focus and simulator sickness can improve training and operational safety.

Purpose of the Study:

• To investigate the relationship between dark focus changes and the incidence of simulator sickness.
• To determine if dark focus shifts can predict or correlate with simulator sickness symptoms.

Main Methods:

• Three experiments were conducted involving college students and pilots.
• Dark focus was measured before and after exposure to simulated flight scenarios (helicopter motion scenes and simulator flights).
• Participants' experience of simulator sickness was recorded and correlated with dark focus measurements.

Main Results:

• Individuals experiencing simulator sickness exhibited specific patterns of dark focus change.
• These patterns included inward (myopic) shifts or attenuated outward shifts in dark focus.
• Results support the hypothesis linking parasympathetic activity, potentially underlying simulator sickness, to myopic dark focus shifts.

Conclusions:

• Dark focus of accommodation is a potential biomarker for simulator sickness.
• Changes in dark focus may occur in various visually demanding environments like virtual reality and microgravity.
• Further research should measure dark focus in these related conditions to understand visual symptomatology.