Ciliary muscle

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Ciliary Muscle

File:Ciliary muscle.png
Illustration of the ciliary muscle

The ciliary muscle is a ring-shaped muscle in the human eye that controls the shape of the lens. It is part of the uvea, which also includes the iris and the choroid. The ciliary muscle is responsible for accommodation, the process by which the eye adjusts its optical power to maintain a clear image or focus on an object as its distance varies.

Structure[edit | edit source]

The ciliary muscle is located in the ciliary body, which is attached to the lens by the zonule of Zinn. It is divided into two parts: the circular ciliary muscle (or ciliary ring) and the radial ciliary muscle (or ciliary processes). The circular ciliary muscle, which is the innermost part, affects the zonules of Zinn, which in turn control the shape of the lens. The radial ciliary muscle, which is the outermost part, controls the position of the lens.

Function[edit | edit source]

When the ciliary muscle contracts, it releases the tension on the zonules of Zinn, allowing the lens to become more convex, thus increasing its optical power. This allows the eye to focus on near objects. Conversely, when the ciliary muscle relaxes, it increases the tension on the zonules of Zinn, causing the lens to become less convex, thus decreasing its optical power. This allows the eye to focus on far objects.

Clinical significance[edit | edit source]

Dysfunction of the ciliary muscle can lead to a number of vision disorders, including presbyopia, which is the loss of the ability to focus on near objects, and astigmatism, which is a distortion of the image on the retina due to irregularities in the cornea or lens.

See also[edit | edit source]

References[edit | edit source]



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