Anatomy of the Eye

The visible part of your eye is called the eyeball. The eyeball is a sphere, approximately 2.5 cm in diameter. Various parts of your eyes correspond to the key parts of a camera. They also function in a similar manner. Light passes through the clear transparent cornea, equivalent to the lens cover, into your eyes, the camera. The iris acts as a diaphragm of the camera. It expands and contracts according to the brightness of the light and so controls the amount of light entering your eyes. This is done by controlling the size of the pupil, the aperture in the camera. The brighter the light, the more it contracts. In dark conditions, the pupil becomes large to admit more light into the eye. Light passes through the media or the cornea, aqueous, pupil, lens and vitreous to focus on your retina, equivalent to the photographic film. As in a camera, to obtain a good image, it is necessary that all the media be clear. Depending on the distance of the object from the eye, the lens can become flatter or thicker to focus the object’s image on the retina. This process is known as accommodation. The optic nerve carries the information of the image of any object, to the occipital cortex of the brain, where the center for sight is located. Here the message is interpreted and you see the object.