Fixating on a laser-projected point at a constant distance suppresses periodic eye movements and impairs balance control during cycling.

The visual field is influenced by movements of the body, head, and eye movements during self-motion. Therefore, compensatory eye movements that stabilize the visual field are crucial for perceptual-motor control. In cycling, a type of eye movement known as optokinetic nystagmus may help prevent visual blur and support the use of retinal flow for maintaining dynamic balance. This study aimed to examine the impact of visual environmental manipulation on dynamic balance control in cycling by altering gaze behavior. Participants cycled under three conditions and were instructed to ride as slowly as possible while staying on the path. In the control condition, they cycled along a striped path. In the laser condition, they cycled on the same path while fixating on a laser point projected 4 m ahead of the bicycle. In the monochrome condition, participants cycled along a plain white path. Each condition consisted of five trials. The results showed that the amplitude at the peak frequency of eye movements was significantly lower in the laser condition compared to the control and monochrome conditions. In addition, the cycling distance and duration were significantly shorter in the laser condition compared to the control condition. There were no significant differences in eye movements or cycling performance between the control and monochrome conditions. These results suggest that fixating on a laser point projected at a constant distance ahead suppresses the amplitude of eye movements and impairs balance control during cycling. Natural gaze behavior is likely to be an important factor for cycling safely.