Which lens condition is characterized by the inability of the eye to maintain focus on an object?

The condition characterized by the inability of the eye to maintain focus on an object is known as accommodation. Accommodation refers to the eye's ability to change its focus from distant to near objects and vice versa by altering the shape of the lens. When this ability is impaired, typically due to factors like fatigue or certain eye conditions, it results in difficulty focusing clearly.

In the context of this question, choosing accommodation as the correct answer highlights the active process of the eye's lens adapting to focus. This process is crucial for clear vision at varying distances. Factors that can disrupt accommodation include age or specific visual impairments. Understanding accommodation is essential in optics and vision science, as it forms the basis of how the eye adjusts for clarity during different tasks.

The other choices presented refer to specific conditions related to vision but do not directly describe the inability to maintain focus as precisely as accommodation does.