Define exophoria and esophoria.

• A. Exophoria is a latent outward misalignment.
• B. Exophoria is a manifest inward misalignment.
• C. Esophoria is a latent outward misalignment.
• D. Esophoria is a manifest outward misalignment.

Answer: (A)

Exophoria and esophoria describe latent, or phoric, misalignments of the eyes. A phoria is only revealed when binocular fusion is disrupted; with fusion intact, the eyes appear aligned.

Exophoria is a tendency for one eye to drift outward, but this outward drift is kept in check by fusion during normal viewing. When fusion is temporarily broken (as in dissociating tests), the outward drift becomes evident. That’s why exophoria is described as a latent outward misalignment.

In contrast, esophoria would be a latent inward drift, not outward. If the misalignment were always present and visible regardless of fusion, that would be a tropia (for example, exotropia outward and esotropia inward), not a phoria.

So the correct description is that exophoria is a latent outward misalignment.