The human eye is an organ which reacts to light and pressure. As a sense organ, the mammalian eyeallows vision. ... Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth.

The eye is an optical instrument and also one of our five sense organs. the eye help us in viewing objects. this happens only when light from the object enters our eyes.The eye has a spherical shaped structure with a slight bulge in the front part the outer covering of the eyes protect it from injuries.The front part of ice is covered by a transparent is spherical membrane called cornea. Light enters the eyes through the cornea. Just behind the cornea, there is a dark coloured muscular diaphragm called the Irish with a small circular opening in the middle called pupil. The Pupil appears black because no light is reflected from it . the Iris regulate the amount of light entering the eyes by adjusting the size of pupil. when the intensity of light is more the Iris Makes The Pupil contract and hence the amount of light entering the eyes decreases.