What is the purpose of the ciliary body in the eye?

The ciliary body plays a crucial role in the functioning of the eye by performing two main functions: controlling the shape of the lens and secreting aqueous humor.

The ciliary body is composed of ciliary muscle and ciliary processes. The ciliary muscle adjusts the shape of the lens, allowing the eye to focus on objects at varying distances—a process known as accommodation. When the ciliary muscle contracts, the tension on the lens decreases, enabling it to become more rounded for near vision. Conversely, when the muscle relaxes, the lens flattens for distant vision.

Additionally, the ciliary processes are responsible for producing aqueous humor, the clear fluid that fills the space between the lens and the cornea. This fluid is vital for maintaining intraocular pressure, providing nutrients to avascular structures like the lens and cornea, and facilitating the removal of metabolic wastes.

The other options do not accurately represent the specific functions of the ciliary body, as they address different aspects of ocular physiology.