Question

What is the function of the lens in the human eyes?

Answer 1

Hint: We know that the eye lens of humans is transparent and crystalline. It is biconvex and responsible for focusing light on the retina. It is present behind the cornea and attached to the ciliary body by ligaments.

Complete answer:
The main characteristics of humane lens are:
- It lacks blood vessels. Aqueous humor provides nourishment to it. Both vitreous body and aqueous humor bathe the lens.
- It is transparent, ellipsoidal, crystalline and biconvex. The posterior part is more curved than the anterior part of the lens.
- It is held at its place by ligaments attached to the ciliary body.
- The anterior portion of the lens is covered by iris. It is a pigmented extension of the ciliary body and controls the amount of light passing through the lens.
-The aperture of the lens surrounded by iris is known as the pupil.
- The ciliary muscles change the shape of the lens and control the focus of the lens. The ability of the lens to adjust and focus differently placed objects is known as accommodation.
- The outermost transparent layer of the lens is known as the lens capsule.
- The lens fiber cells constitute the major portion of the lens. They are elongated and transparent cells.
- The lens epithelium is present between the capsule and fibers at the anterior portion. It is made up of simple cuboidal epithelium. New lens fibers are generated from the epithelial cells
- Ninety percent of proteins within the lens are made up of water soluble proteins known as crystallins.

Note:
We also have to know that the lens is located in the eye. By changing its shape, the lens changes the focal distance of the eye. In other words, it focuses the light rays that pass through it (and onto the retina) in order to create clear images of objects that are positioned at various distances. It also works together with the cornea to refract, or bend, light.