The ciliary body is primarily responsible for which function?

The ciliary body plays a crucial role in the process of accommodation, which is the ability of the eye to change the shape of the lens to focus on objects at varying distances. This is achieved through the contraction and relaxation of the ciliary muscles, which are part of the ciliary body. When the ciliary muscles contract, they release tension on the zonules (also known as the zonular fibers or suspensory ligament of the lens) that hold the lens in place. This allows the lens to become more rounded, enhancing its refractive power for viewing nearby objects. Conversely, when the ciliary muscles relax, the tension on the zonules increases, flattening the lens for distance vision.

Other functions associated with the eye, such as tear production, light regulation, or light detection, are carried out by different structures. Tear production is primarily handled by the lacrimal glands, while the iris regulates the amount of light entering the eye. Light detection occurs in the retina, where photoreceptor cells respond to light stimuli. Thus, the role of the ciliary body is specifically tied to altering the shape of the lens for clear vision at various distances.