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ciliary body
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Diagram of a horizontal section of the human eye showing labeled parts including the cornea, iris, lens, retina, sclera, optic nerve, and blood vessels, with internal structures and muscles visible. Figure 1: General structure of the mammalian eye.
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ciliary body

anatomy
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Diagram of a horizontal section of the human eye showing labeled parts including the cornea, iris, lens, retina, sclera, optic nerve, and blood vessels, with internal structures and muscles visible.
cross section of the human eye A horizontal cross section of the human eye, showing the major parts of the eye, including the protective covering of the cornea over the front of the eye.

The ciliary body is a vascular structure within the eye that encircles the inner surface behind the iris. It plays a crucial role in two main functions: secreting aqueous humor and controlling the eye's focus.1

The ciliary body contains the ciliary muscle, which alters the shape of the lens for clear vision at different distances. When viewing distant objects, this muscle relaxes, flattening the lens. For near objects, the muscle contracts, causing the lens to bulge and increase its focusing power. This process is known as accommodation.23

Additionally, the ciliary body's specialized cells form the aqueous humor, a fluid that fills the front chambers of the eye. This fluid nourishes the lens and cornea, which lack blood vessels, and maintains intraocular pressure, essential for the eyeball's shape.435

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6 Britannica Sources
  1. ciliary body
  2. focusing
  3. aqueous humour
  4. human eye - The uvea
  5. eye disease - Diseases and disorders of the lens
  6. eye disease - Uveitis

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