A condition in which if an eye is covered it tends to squint.
A tendency to squint. Under normal circumstances both the eyes work together and look at the same point simultaneously, but if one eye is covered it will move out of alignment with the object the other eye is still viewing. When the cover is removed the eye immediately returns to its normal position. Most people have a small degree of the type of heterophoria known as exophoria, in which the covered eye tums outward, away from the nose. Heterophoria often produces eyestrain because of the unconscious effort required to keep the two eyes coordinated.
A tendency of the eyes to deviate from their normal position for visual alignment, especially when one eye is covered; latent deviation or squint. This tendency is caused by an imbalance or weakness of the ocular muscles.
A broad term encompassing any tendency of the eyes to deviate from their correct position for binocular vision. Actual squinting only occurs when one eye is covered, as the desire for binocular vision is strong enough to compensate for the muscle imbalance in the eyes. Nonetheless, there are specific terms to describe the direction of each deviation. Esophoria refers to an inward deviation, exophoria to an outward deviation, hyperphoria to an upward deviation, hyperesophoria to an upward and inward deviation, and hyperexophoria to an upward and outward deviation.