The ciliary body belongs to a subset of organs in the eyeball. Located between the iris and choroid, the ciliary body ensures that the eye receives adequate amounts of the liquid aqueous humor, which provides nutrition to tissues and helps to maintain the right amount of pressure within the eyeball.
It also contains the ciliary muscle, which contributes to the shrinking and flattening of the lens when you focus on something, otherwise known as eye accommodation. The front part of the ciliary body forms ciliary protrusions and the ciliary muscle. The back part is flat and does not contain pigment cells. From ciliary protrusions extend thin fibers that form a suspension apparatus of the lens, and together with the contraction of the ciliary muscle, provide eye accommodation.