THE EYE by Dr. John Askill, Millikin University. The Retina is the the inside surface of the back of the eye. It consists of an array of photoreceptors called rods and cones which transduce the light energy into electrical signals which are transmitted to the brain by the optic nerve. There are about 6 million cones in each eye, and are most densely concentrated in the central area of the retina reducing in number toward the peripheral retina.
Cones are responsible for seeing fine details and for color vision.
The retina plays the role of the film in a camera. The Iris is the colored part of the eye. It adjusts automatically to control the amount of light entering the eye. The pupil is the opening in the iris through which the light enters. It appears black because no light is reflected from it.