How the Eye Works

he human eye is similar to a camera. Light enters the cornea, a transparent cover that resembles a camera aperture. The iris, similar to a camera shutter, opens and closes (making the pupil bigger and smaller) to regulate the amount of light passing through. The light rays pass through the lens and focus on the retina.  Like a camera film, the retina senses the incoming light and creates electrical impulses. These impulses are sent via the optic nerve to the brain where an image is produced.

Aqueous Body: the thin, clear fluid between the cornea and the iris.  This fluid provides nutrients to the cornea and the lens.

Choroid: the thin, vascular membrane between the retinal and sclera.  The choroid is composed of layers of blood vessels that provide nourishment to the outer layers of the retina.

Ciliary Body: the part of the eye that produces aqueous humor.

Cornea: the clear front window of the eye.  The cornea provides most of the focusing power when light enters the eye.

Iris: the colored part of the eye.  The iris adjusts the size of the pupil and regulates the amount of light that enters the eye.

Lens: the transparent structure behind the pupil that focuses light rays onto the retina.

Macula: the small, highly sensitive area in the retina.  The macula is responsible for fine, detailed central vision.

Optic Nerve: the nerve that connects the eye to the brain.  The optic nerve transmits electrical impulses from the retina to the brain, which interprets them as images.

Pupil: the dark center in the middle of the iris.  The pupil determines how much light is let into the eye.

Retina: the nerve layer that lines the back of the eye.  The retina senses light and creates impulses that are sent via the optic nerve to the brain.

Sclera: the tough, opaque tissue that serves as the eye’s protective outer coat.

Vitreous: the transparent, jelly-like substance that fills the eye’s cavity. It is composed mainly of water and helps to maintain the shape of the eye.