phoria
Pronunciation: FOR-ee-ah
A latent eye misalignment that is normally controlled by binocular fusion but becomes apparent when fusion is disrupted.
Full Definition
Phoria refers to a tendency for the eyes to deviate from perfect alignment when binocular fusion is interrupted, such as during cover testing. Unlike a tropia (manifest strabismus), a phoria is latent and typically asymptomatic because the brain's fusion mechanisms maintain single binocular vision. However, large phorias or decompensated phorias can cause symptoms including eyestrain, headaches, and diplopia. Common types include exophoria (outward deviation tendency) and esophoria (inward deviation tendency).
Usage
Usage note: Always specify direction (exophoria, esophoria, hyperphoria) and magnitude when documenting.
In Context
- "Cover testing revealed a 6 prism diopter exophoria at distance with good fusional reserves." — Binocular vision assessment
- "The patient's intermittent diplopia was attributed to decompensation of a previously asymptomatic esophoria." — Progress note