This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
The eye is almost globular in outline; its thickness=2.3 cm. The external part of the eye is reasonably strong, white in color and is known as sclera. The crystal clear anterior outer casing of the eye is referred to as cornea. At the back of cornea is the tinted membrane known as iris; the iris not only controls the quantity of light going into the eye but also delivers color to the eye. In the iris is a black rounded hole known as the pupil, the size of which is regulated by the iris. At the back of the pupil is the lens which is denser in the center and serves to assemble the light rays falling on it. The lens concentrates this light on a slender layer of nerve cells called the retina.