Paragraph on “What is the structure of the eye and how does it work?” complete paragraph for Class 9, Class 10, Class 11 and Class 12

What is the structure of the eye and how does it work?

The eye is shaped like a ball, but it is not perfect sphere, each eyeball has a thick white converging which has a transparent section in front called the cornea. There is a space behind the cornea which is filled with a clear fluid, and behind that is the iris- a ring of muscles which forms the coloured part of the eye. The opening in the middle of the iris is called the pupil. The muscles of the iris alter the size of the pupil so that it contracts in bright light and expands in dim light.

The light entering the eye then passes through the lens. The eye lens acts in the same way as the lens in a camera. The muscles attached to its rim alter its shape so that the light rays are focused on the retina.

The eye cavity- the space between the lens and the retina- is filled with a sticky jelly – like fluid called citreous humor. 

The retina is like a photographic film and it has three layers of nerve cells with the light receptors- the rods and cones- on the outside. The rods and cones convert light into nerve impulses which travel via the optic nerve to the brain. The ‘picture’ on the retina is much smaller than the original, or course , and is upside down. The brain interprets the ‘ picture’ correctly, so that what we see is not distorted.