• A part of the middle layer of the wall of the eye. The ciliary body includes the ring-shaped muscle that changes the size of the pupil and the shape of the lens when the eye focuses. It also makes the fluid that fills the eye.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• Circumferential tissue located behind the iris and composed of muscle and epithelium.
  CDISC Terminology
  Clinical Data Interchange Standards Consortium (CDISC), 2021
• Part of the eye that produces the aqueous humor (fluid that nourishes the eye) and contains the ciliary muscle, which controls focusing of the lens.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• Tissue located behind the iris and composed of muscle and epithelium. Its functions include the production of aqueous humor and changing the shape of the crystalline lens.
  NCI
  U.S. National Cancer Institute, 2021