Which structure of the eye adjusts its shape to focus on near or far objects?

The lens is the structure of the eye that adjusts its shape to focus on near or far objects, a process known as accommodation. When viewing distant objects, the ciliary muscles relax, causing the lens to become flatter, which helps focus light rays more directly onto the retina. Conversely, when looking at nearby objects, the ciliary muscles contract, resulting in a more rounded lens that increases its refractive power, allowing for a clearer image of closer objects.

This ability to change shape and focus accurately is critical for normal vision as it ensures that the images we see are sharp, regardless of the distance from which they originate. The lens works in conjunction with other structures in the eye, but its unique capability to change its curvature directly contributes to our ability to see clearly at various distances.