It has become accepted that the horse cannot see directly in front when his nose is lowered and thus the horse must rely on the rider. The hypothesis was tested that this conclusion would be correct only if the horse did not adjust the eyeball horizontalaxis to changes of the head position. The results of the present study suggest that it is unlikely that horses have limited vision in relation to their head position when driven by the rider, and that the horse maintains the optimal horizontal eyeball position regardless of head position relative to the ground.