Ciliary body (eye)

Last revised by Craig Hacking on 3 May 2023

Citation, DOI, disclosures and article data

Citation:

Raju A, Hacking C, Weerakkody Y, et al. Ciliary body (eye). Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-154881

DOI:

https://doi.org/10.53347/rID-154881

Permalink:

https://radiopaedia.org/articles/154881

rID:

154881

Article created:

22 Oct 2022, Arjun Raju

Disclosures:

At the time the article was created Arjun Raju had no financial relationships to ineligible companies to disclose.

View Arjun Raju's current disclosures

Last revised:

3 May 2023, Craig Hacking ◉ ◈

Disclosures:

At the time the article was last revised Craig Hacking had the following disclosures:

Philips Australia, Paid speaker at Philips Spectral CT events (ongoing)
Taylor and Francis Publishing, Paid author of Imaging for Students 5th edition (ongoing)

These were assessed during peer review and were determined to not be relevant to the changes that were made.

View Craig Hacking's current disclosures

Revisions:

5 times, by 4 contributors - see full revision history and disclosures

Systems:

Head & Neck

Sections:

Anatomy

Synonyms:

ciliary bodies

The ciliary body is the continuation of the uveal layer of the eye and functions in the production of aqueous humor and the process of lens accommodation.

location: between the vitreous body and posterior chamber of the globe
function: aqueous humor production and accommodation of the lens
arterial supply: anterior ciliary arteries and long posterior ciliary arteries
venous drainage: vorticose veins
innervation: short ciliary nerves
relations: vitreous cavity posteriorly, posterior chamber anteriorly, scleral layer externally, retinal layer internally

Gross anatomy

The ciliary body is a continuation of the uveal tract, with the choroid lying posteriorly and iris anteriorly. The uveal tract lies between an outer scleral layer and inner retina layer of the eye ¹. It forms a flat ring and contains the ciliary process, ciliary muscles and ciliary vessels.

The ciliary processes are finger like protrusions of the ciliary body and attach to the lens via the zonula fibers (suspensory ligaments), allowing for the process of accommodation. The ciliary processes contain specialized vascular epithelium that secrete aqueous humor into the globe of the eye ¹.

The ciliary muscles consist of three differently oriented smooth muscle fibers. The outermost longitudinal fibers attach the ciliary body to the scleral spur and function to open the trabecular network and Schlemm’s canal ². The innermost circular fibers relax the zonular fibers when contracted, allowing for an increase in lens axial diameter and convexity. Radial or oblique fibers lie in between and connect the two layers ².

The ciliary body is supplied by the anterior ciliary arteries and the long posterior ciliary arteries which anastomose and form a vascular ring around the root of the iris. It is drained by the vorticose veins and then into the superior and inferior orbital veins.

The ciliary body receives parasympathetic innervation from the Edinger-Westphal nucleus in the midbrain and travels via the oculomotor nerve to the ciliary ganglion. This ganglion gives off short ciliary nerves which innervates the ciliary body.

Histology

The ciliary body contains two layers of cuboidal epithelium. The deep layer is heavily pigmented due to high vascularity and high level of melanin. The surface layer is non-pigmented, non-photosensitive extension of the receptor layer of the retina and is responsible for aqueous humor production ³.