Ciliary body - general

Author: Nat Pernick, M.D. (see Authors page)

Revised: 23 May 2018, last major update February 2014

Copyright: (c) 2004-2018, PathologyOutlines.com, Inc.

PubMed Search: Ciliary body[title] eye review[ptyp]

Cite this page: Pernick, N. Uvea: ciliary body - general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/eyeuveaciliarybodygeneral.html. Accessed December 14th, 2018.
Definition / general
  • Middle segment of uveal tract, between iris and choroid
  • Composed of pars plicata and pars plana
  • Holds lens in place
  • Cyclectomy: resecting portion of ciliary body containing tumor; may also include other surrounding structures
  • Pars plicata: 70 sagitally oriented folds or ciliary processes that gradually merge with posterior flat pars plana, which merges posteriorly with serrated, anterior border of retina (ora serrata)
  • Ciliary epithelium composed of inner epithelial layer (nonpigmented, contiguous with aqueous of posterior chamber) and outer epithelial layer (pigmented, unites with retinal pigment epithelium at ora serrata)
  • Outer epithelial layer overlies PAS+ basal lamina that thickens in diabetes mellitus
  • Zonules: acellular fibers that attach crests of nonpigmented ciliary epithelium in pars plicata to capsule of crystalline lens
  • Ciliary body has 3 distinct bundles of smooth muscle which assist in accommodation; as muscle contacts, ciliary body extends forward, reducing pressure on zonules, enabling lens to become less concave, thereby increasing its refractive power
Microscopic (histologic) images

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Ciliary body, iris and lens

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Ciliary process zonule fibers