The ciliary body is a circular structure that is an extension of the iris, the colored part of the eye. The ciliary body produces the fluid in the eye called aqueous humor. It also contains the ciliary muscle, which changes the shape of the lens when your eyes focus on a near object. This process is called accommodation.
A type of tumor called melanoma can develop in the iris. Most eye melanomas form in the part of the eye that you cannot see in the mirror and therefore they can be difficult to detect. Early melanomas do not cause any symptoms making them hard to diagnose.
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References
Evans M. Anatomy of the uvea. In: Yanoff M, Duker JS, eds. Ophthalmology. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 7.1.
Stålhammar G, Coupland SE, Ewens KG, et al. Improved staging of ciliary body and choroidal melanomas based on estimation of tumor volume and competing risk analyses. Ophthalmology. 2024;131(4):478-491. PMID: 38071620 pubmed.ncbi.nlm.nih.gov/38071620/.
Standring S. Eye. In: Standring S, ed. Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. Philadelphia, PA: Elsevier; 2021:chap 45.
Review Date 7/24/2025
Updated by: Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.