Ciliary muscle

The **ciliary muscle** is a smooth muscle structure in the eye, located within the ciliary body of the uveal tract[4][1]. It is responsible for **controlling ocular accommodation**, the process by which the lens changes shape to focus on near or distant objects. The muscle is innervated mainly by parasympathetic fibers from the oculomotor nerve (cranial nerve III), acting through M3 muscarinic receptors. Contraction of the ciliary muscle reduces tension on the zonular fibers, making the lens rounder for near vision (accommodation); relaxation allows the lens to flatten for distance vision[1][4]. It also participates in regulating aqueous humor dynamics by widening the iridocorneal angle and facilitating drainage via the canal of Schlemm[1]. Smooth muscle relaxing or contracting agents affecting the ciliary muscle are important in therapies for glaucoma and in diagnostic mydriasis and cycloplegia[9][6]. Although critical for eye function, the **ciliary muscle itself is not a conventional molecular drug target** like a receptor protein or enzyme; rather, it is a tissue made up of smooth muscle cells. Disorders can involve dysfunction (accommodation problems) or rare tumors, such as mitochondria-rich leiomyoma[8]. It is important to note this entry refers to an anatomical tissue—not a molecular target—and is therefore considered **incorrect as a canonical drug target** under standard pharmacological nomenclature.

Other names

Intrinsic ocular muscleIntraocular muscleEye ciliary muscle

Muscarinic receptor (primarily M3) activation (contraction), muscarinic receptor blockade (relaxation/cycloplegia), Beta-adrenergic blockade (modulation of autonomic tone)