The role of vision and spatial orientation in the maintenance of posture.

This article reviews and analyzes the role of vision and spatial orientation in maintaining posture and balance. The key issues that relate to the development of postural control across the life span are discussed. Use of vision as a critical source of information that specifies spatial orientation in the environment is considered. We argue that the visual system functions as part of the perception-action cycle as promoted in ecological psychology by James Gibson. We compare and contrast theory and evidence of both standard and ecological accounts of how the visual system perceives the information and the findings relative to the role of the retinal vision in processing and acting on information related to motion. Changes in the ambient optical array (optical flow) as a non-force field are compared with gravity-based perturbations relative to the possible influence of the non-force field to changes in the motor system. Finally, a summary of some of our own work is presented, with comments about implications for further research and possible applications to clinical practice.