The lens is an important part of the structure of the eye.
The lens of the human eye is a transparent structure enclosed in a thin transparent capsule. It is located behind the pupil of the eye and encircled by the ciliary processes, which slightly overlap the edges of the lens.
What does the lens do ?
The lens helps to refract light passing through the eye, that light being first refracted by the cornea (which is located at the front of the eye). The lens focuses light into an image on the retina. It is able to do this because the shape of the lens is changed according to the distance from the eye of the object(s) the person is looking at. This adjustment of shape of the lens is called accomodation and is achieved by the contraction and relaxation of the ciliary muscle.
The structure of the Lens
The capsule of the lens is a transparent, brittle, yet highly elastic membrane that is thicker in front of the lens than behind it
The lens itself is a transparent, biconvex body of approx. 9-10 mm diameter and approx. 4 mm from front to back. The basic structure of the lens is composed of concentric layers.
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.