Definition: A phoria is a latent deviation, or misalignment, of the eyes that is only apparent some of the time. A phoria appears when fixation on a single object is broken and the eyes are no longer looking at the same object.
For example, during the cover test portion of an eye examination, your eye doctor will alternately cover and uncover your eyes while you fixate on a target. If your eye moves upon being uncovered, you have a phoria.
If a large amount of phoria is detected, your eyes are not aimed at the target while at rest. Keeping both eyes fixated on the target requires an effort by you, possibly causing eyestrain or headaches.
Also Known As: Heterophoria, orthophoria
