The eye is a complex organ composed of many small parts, each vital to normal vision. The ability to see clearly depends on how well these parts work together. It is actually an extension of the brain, connected by the optic nerve, which consists of thousands of nerve fibers. These nerves carry visual messages, in the form of nerve impulses, from the retina to the brain, which interprets the impulses as images.

The sclera, or white visible portion of the eye, forms the outermost layer of tissue of the posterior and lateral aspects of the eyeball. It consists of a firm fibrous membrane that maintains the shape of the eye and attachment to the extraocular or extrinsic muscles of the eye.

The clear, dome-shaped surface that covers the front of the eye. Being the front window of the eye, it is the main source of refraction. The cornea has the dual purpose - protecting the eye and refracting light as it enters the eye. The cornea is as strong and durable as plastic and as smooth and clear as glass, which means it is also an excellent shield against dust, germs and other debris. While the cornea contains no blood vessels, it is packed with nerve fibers, making it highly sensitive to pain.

The thin blood-rich membrane, that lies between the retina and the sclera. It is made up of blood vessels that provide nourishment to the eye and is responsible for supplying blood to the retina.

Is a part of the eye that produces aqueous humor. It contains two main structures - the first is a muscle that contracts and expands to control the curvature of the lens during accommodation and the second is a gland that secretes aqueous humor.

The colored part of the eye. It is partly responsible for regulating the amount of light permitted to enter the eye. The iris has three layers and is distinctive because of its genetically determined coloring.

Immediately behind the iris is the Lens, it is the transparent structure inside the eye that focuses light rays onto the retina. Located just behind the pupil it allows for changing of focus from distance to near objects by altering its shape. This changing focus is called Accommodation. As people age, the lens can harden, decreasing focusing ability.

The opening in the middle of the iris through which light passes to the back of the eye. It is the light sensitive nerve layer that lines the back of the eye. Its size changes since its function is to control the amount of light reaching the retina. In the dark, it expands allowing more light to enter. It contracts in bright light to keep out excess light.

A bundle of nerve fibers that connect the retina with the brain. The optic nerve carries signals of light, dark, and colors to the area of the brain (the visual cortex), which assembles the signals into images. This nerve is the pathway that the light rays take from the retina to the processing centre of the brain. It actually is made of about a million tiny nerves bundled together.

This area is not sensitive to light and it is often referred to as the "blind spot". It is where the retina meets the optic nerve.

Is a clear watery fluid in front of the eyeball. This fluid is produced by the ciliary body and circulates in the front part of the eye. It provides nourishment to the front parts of the eye and maintains the eye pressure.

Top, movable, superior fold of skin that covers the front of the eyeball when closed, including the cornea.

A clear, jelly-like, substance that fills the back part of the eye. This clear gel fills the central core of the eye. It helps to maintain a spherical shape to the eye.