What is the primary function of the ciliary body in the eye?

The ciliary body plays a crucial role in the process of accommodation, which is essential for focusing light onto the retina. This structure, located behind the iris, contains the ciliary muscles that adjust the shape of the lens. When the ciliary muscles contract, they release tension on the zonules (ligaments holding the lens in place), allowing the lens to become more rounded. This rounding of the lens is necessary for focusing on nearby objects, while relaxation of the ciliary muscles allows the lens to flatten for distance vision. Through this mechanism, the ciliary body directly assists in ensuring that light is properly focused on the retina, enabling clear vision at varying distances.