Which term describes a condition where one eye deviates while focusing on an object?

The term that describes a condition where one eye deviates while focusing on an object is strabismus. Strabismus occurs when the eyes are not properly aligned with each other and can cause issues with binocular vision. In this condition, one eye may turn inward, outward, upward, or downward, leading to a misalignment that can affect depth perception and visual clarity.

While tropia, which is also related to eye misalignment, specifically refers to a type of strabismus where the deviation is constant and noticeable, strabismus encompasses more than just tropia—it includes various forms of misalignment. Esophoria is a more subtle condition where there’s a tendency for one eye to drift inward when the eyes are relaxed, but it does not involve a constant deviation during focusing.

Therefore, strabismus is the most appropriate term that broadly captures the condition where one eye deviates from proper alignment while attempting to focus on an object.