Final answer:
Diplopia is a vision symptom characterized by double vision resulting from a failure in conjugate gaze. Decompensated phoria can cause eye strain and diplopia.
Step-by-step explanation:
Diplopia is a vision symptom characterized by double vision resulting from a failure in conjugate gaze. Decompensated phoria is a type of eye movement disorder where the eyes are unable to maintain proper alignment, leading to eye strain and diplopia. In this condition, the eyes may have difficulty working together, causing the person to see two images instead of one.