Related Experiment Video
Updated: Jul 2, 2026
Experimental Methods to Study Human Postural Control
Published on: September 11, 2019
Vertical phoria and postural control in upright stance in healthy young subjects
1IRIS Group CNRS/FRE 3154: Service d'Ophtalmologie, Hôpital Européen Georges Pompidou, 20 rue Leblanc, 75908 Paris Cedex 15, France. matheron@wanadoo.fr
Objective:
To test the quality of postural performance in quiet upright stance in healthy young adults with vertical heterophoria (VH) within the normal range and without VH (vertical orthophoria, VO).
Methods:
Twenty-six subjects took part in this study. The postural stability was measured with a force platform while the subjects fixated a target at eye level in a straight ahead position, placed at either 40 or 200cm.
Results:
The results indicated that the postural control was better for subjects with VO than subjects with VH. Particularly, there was an interaction between vertical phoria and distance: the subjects with VH showed greater instability than the subjects with VO at a far distance only. An additional study showed that the cancellation of VH with a prism improved postural stability.
Conclusions:
The quality of postural performance in quiet upright stance was lower in the subjects with VH. We speculate that VH, even when small in size, indicates a perturbation of the somatosensory/proprioceptive loops involved in postural control.
Significance:
Vertical phoria could perhaps indicate the capacity of the central nervous system to integrate optimally proprioceptive cues.
