Your eye is a slightly asymmetrical globe, about an inch in diameter. The front part includes:
Iris: The colored part
Cornea: A clear dome over the iris
Pupil: The black circular opening in the iris that lets light in
Sclera: The white of your eye
Conjunctiva: A thin layer of tissue that covers the entire front of your eye, except for the cornea
Just behind the iris and pupil lies the lens, which helps focus light on the back of your eye. Most of the eye is filled with a clear gel called the vitreous. Light projects through your pupil and lens to the back of the eye. The inside lining of the eye is covered by special light-sensing cells that are collectively called the retina. It converts light into electrical impulses. Behind the eye, your optic nerve carries these impulses to the brain. The macula is a small extra-sensitive area in the retina that gives you central vision.
Eye color is created by the amount and type of pigment in your iris. Multiple genes inherited from each parent determine a person’s eye color.