What happens when the ciliary muscles relax?

Parasympathetic activation of the M3 muscarinic receptors causes ciliary muscle contraction, the effect of contraction is to decrease the diameter of the ring of ciliary muscle (causing constriction of the pupil and accommodation). The zonule fibers relax and the lens becomes more spherical, increasing its power to refract light for near vision. read more

The ciliary muscle is made of smooth muscle rather than skeletal muscle. These two types of muscles have different mechanisms for contraction and relaxation. Skeletal muscle is relaxed unless it is stimulated by a nerve. read more

When ciliary muscles contract the zonules which are attached to the cillary body changes the direction of its vector force hence the zonules relax. This video gives a better understanding of how this mechanism works. read more