Ciliary Muscle
There is a ciliary muscle located in each eye in the *human body. It is one of three zones of the ciliary body (which connects the choroid with the iris).
Contraction and relaxation of the ciliary muscle alters the curvature of the lens of the eye.
The term used to refer to the adjustment of the shape of the lens to change the focus of the eye is 'accommodation'. This process may be described simply as the balance existing at any one time between between two states:
- Ciliary muscle relaxed:
The suspensory ligaments attached to the ciliary body that hold the lens in place are stretched, causing the lens to be relatively flat.
This enables the eye to focus on distant objects. - Ciliary muscle contracted:
The tension on the suspensory ligaments attached to the ciliary body is reduced allowing the lens to be relatively round.
This enables the eye to focus on close objects (near to the eye).
More about Ophthalmology:
This section includes short definitions and descriptions of the parts of the eye.
For other descriptions in this category, choose from the list
to the left (but note that this is not a complete / exhaustive list).
Other related sections include:
- A labelled diagram of the eye
- A concise description of the human retina with brief descriptions of the parts of the retina
- Diseases and disorders of the human eye and the human visual system
- Clinical and surgical procedures re. eyes and human visual system
For further information see also our pages of books about ophthalmology.
