The power of accommodation refers to the ability of the eye's lens to change its shape in order to focus on objects at different distances. This process is controlled by the ciliary muscle which surrounds the lens and can contract or relax to change the curvature of the lens. As the ciliary muscle relaxes the lens flattens and allowing the eye to focus on distant objects. As the ciliary muscle contracts the lens thickens, allowing the eye to focus on close objects. This process is known as accommodation and is essential for clear vision at all distances.