Introduction: Countermeasures (e.g., drugs, training, etc.) designed to combat the problem of space motion sickness (SMS) have had only limited successes. A possible solution for SMS and terrestrial motion sickness may rest in preventing retinal slip via stroboscopic vision.
Methods: There were 32 subjects who participated in a study to investigate the effect of stroboscopic illumination on motion sickness using either a strobe light or liquid crystal display (LCD) shutter glasses. There were 19 subjects who read text and made +/- 20 degrees head movements in the horizontal plane (yaw) at 0.2 Hz while wearing left-right reversing prisms and exposed to 4-Hz stroboscopic or normal room illumination (control condition). Motion sickness was scored using the Miller and Graybiel scale and subjective self-ratings. In a crossover design, testing was repeated using stroboscopic LCD shutter glasses with an additional 13 subjects and 6 subjects from the first condition.
Results: During the experiment with a strobe light, motion sickness scores were significantly lower than in the control condition (chi 0.32 strobe vs. chi 3.79 light = p < 0.003). Results with the LCD shutter glasses corresponded with those when the environment was strobed in an otherwise dark room (chi 1.0 glasses vs. chi 4.1 light = p < 0.001).
Conclusions: Stroboscopic illumination reduced the severity of motion sickness symptoms, and shutter glasses with a flash frequency of 4 Hz are as effective as a strobe light. Stroboscopic illumination appears to be an effective countermeasure where retinal slip is a significant factor in eliciting motion sickness due to either self- or surround-motion.