Ciliary zonule

Ciliary Zonule (also known as Zonule of Zinn or Suspensory Ligament of Lens) is a ring of fibrous strands forming a zonule (little band) that connects the ciliary body with the crystalline lens of the eye. These fibers, primarily made up of a type of collagen known as fibrillin, are responsible for holding the lens in place.

Structure[edit | edit source]

The ciliary zonule is a system of radially oriented fibers that suspend the lens behind the iris, and in front of the vitreous body. The zonule fibers are primarily composed of fibrillin, a glycoprotein that forms a microfibrillar structure. The zonule originates from the valleys between the ciliary processes and extends to the lens equator, forming a 360-degree attachment.

Function[edit | edit source]

The primary function of the ciliary zonule is to hold the lens in place and enable changes in lens shape for accommodation. When the ciliary muscle contracts, the tension on the zonule fibers is reduced, allowing the lens to become more convex, thereby increasing its optical power for near vision. Conversely, when the ciliary muscle relaxes, the tension on the zonule fibers increases, causing the lens to flatten for distant vision.

Clinical significance[edit | edit source]

Defects in the ciliary zonule can lead to conditions such as ectopia lentis, where the lens is dislocated or misplaced, and presbyopia, a condition associated with aging where the lens loses its ability to change shape for accommodation. In addition, the ciliary zonule is a critical structure in cataract surgery, where the lens is removed and replaced with an artificial intraocular lens.