Light
The amount of light refers to the quantity or intensity of light that enters the eye. It determines how much visual information is received by the retina.
The pupil is a hole in the center of the iris that regulates the amount of light entering the eye.
Iris: The iris is a ring-shaped structure with muscles that controls and adjusts the size of the pupil.
The retina is a layer at the back of the eye that contains cells sensitive to light and helps convert it into neural signals.