The human eye is an organ that is more complicated than many people realize. The eye has several parts that work together in order to help a person see. Below are the essential parts of the eye: Cornea The cornea is located at the front of the eye. It is very sensitive. The cornea is six layers thick. Some types of contact lenses can reshape the cornea. Conjunctiva It feels and looks like saran wrap. The conjunctiva has two main parts. One part covers the inside of the eyelid, and the other part covers the white portion of the eye. Conjunctivitis is a term that is used to describe eye inflammation. Some types of Conjunctivitis are not contagious. Anterior Chamber The anterior chamber is the space located between the between the iris and cornea. It is filled with fluid. Uveitis or iritis are medical terms for inflammation in this area. Sclera The sclera is the white part of the eye. The sclera also maintains the size and shape of the eye. Iris The iris is the colored portion of the eye. There are eyedrops that can be used to dilate this portion of the eye. Pupil The pupil is located in the center of the eye. It helps regulate the amount of light that can enter the eye. Red-eye photos are more common in people with larger pupils. Retina The retina is found in the back of the eye. It has ten layers. One of the layers of the retina has seven million cones and 125 million rods. The cones help detect color. The rods help detect shades of gray and are responsible for vision at night. Lens The lens is the structure inside of the eye that helps focus light on the retina. It is very flexible until we reach our 40's. A clouding of the lens is a medical condition known as cataracts. Cataract surgery can be completed in less than 10 minutes. Optic Nerve The optic nerve transmits impulses from the retina to the brain. Glaucuma is an eye diseases that causes damage to the optic nerve. It is estimated that 2.2 million people in America suffer from glaucoma. Only 50 percent of people who have this condition know that they have it. Approximately 60 million people worldwide suffer from this condition. Vitreous Humor The vitreous humor is the jelly-like substance that helps shape the eye. Eye Muscles The human eye has six extraocular muscles that help control movement. There are also muscles inside of the eye and eyelids.