Final answer:
Phoria is a condition where the eyes are not properly aligned, but the person can still maintain single vision. Different types of phoria include exophoria, esophoria, and hyperphoria.
Step-by-step explanation:
Phoria is a condition where the eyes are not properly aligned. It is different from strabismus, which is a constant misalignment of the eyes. Phoria is a tendency for the eyes to drift out of alignment, but the person can still maintain single vision by using binocular vision. There are different types of phoria, such as exophoria (outward deviation), esophoria (inward deviation), and hyperphoria (vertical deviation). These conditions may require corrective measures like vision therapy or prism lenses.