Anatomy of the Human Eye

Anatomy of the Human Eye

Cornea: The cornea is the clear tissue covering the front of the eye. It is the main focusing element of the eye. Vision will be dramatically, reduced if the cornea becomes cloudy from disease, injuries or infections.

Iris: Colored or pigmented tissue behind the cornea that acts like a muscular diaphragm, regulating the amount of light that goes into the pupil.

Lens: Transparent body behind the iris that is controlled by the ciliary muscle. The iris provides 25 percent of the eye's focusing power. To focus on close-up objects, the ciliary muscle squeezes the lens to make it thicker. For far-away objects, it flattens the lens to make it thinner.

Optic nerve: The bundle of nerve fibers that transmits light-generated electrical impulses from the retina to the brain.

Pupil: The space in the center of the iris where light enters the inner eye. The widening, or dilation, of the pupil is controlled by the iris.

Retina: The inner layer at the back of the eye, where light-sensitive rods and cones are located. Chemical changes in the retina transmit electrical signals through the optic nerve to the brain to produce sight.