Optic Flow

The pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by relative movement between the observer and the scene. Optic flow provides critical information about self-motion, speed, direction, and the structure of the environment. It plays a key role in maintaining balance and posture — disruptions to optic flow (such as those caused by VR head-mounted displays) can cause postural instability and gait disturbances. For people with mobility impairments who rely more heavily on visual cues for balance, disrupted optic flow in VR is particularly problematic.