Part of the eye which controls the entering of light is called

Part of the eye which controls the entering of light is called Iris.
The iris is a ring-shaped structure made of black muscle tissue that is located beneath the cornea. The eye's color is determined by the color of the iris. By changing the iris, the iris also helps to regulate or modify exposure. The iris' function is to regulate how much light enters the eye.
Iris is a dark muscular structure behind the cornea, which controls the amount of light entering into the eye.