How Does the Eye Use Light?

The eye is a sensory organ that uses light to provide vision. The eye consists of many parts that work together to let in light, detect the quality and characteristics of light, and see. Without light, vision is not possible.

The Cornea

• The cornea is the external surface of the eye. Light bounces off an object, then reaches the cornea, which acts as a powerful lens and bends the lightwaves.

The Pupil

• The pupil appears black, and is located at the front of the eye.

  Light enters the eye through the pupil, a circular opening in the front of the eye. The pupil can dilate and constrict to allow different levels of light in, depending on the intensity of the light.

The Lens

• The lens is located behind the pupil within the eye. The lens fine-tunes the convergence of lightwaves bent by the cornea by further bending them. Ciliary muscles, which hold the lens in place, can alter the shape of the lens to focus on objects that are closer or farther away.

The Retina

• The retina, located at the back of the eye, is home to receptors called rods and cones. Rods are limited to black and white vision, but can work in dimly lit conditions, where as cones provide colors but require more light to function. Converged lightwaves stimulate the receptors, which are connected to the optic nerve. The optic nerve carries the information from the eye to the brain, where it is interpreted and results in vision.