Anatomy of the Eye
In the dark your pupil enlarges to allow more light into your eye and in the light it decreases in size.Light from an object passes through the clear window of the eye known as the cornea. The amount of light allowed into the eye is controlled by the pupil which opens and closes similarly to the workings of a camera shutter. In the dark your pupil enlarges to allow more light into your eye and in the light it decreases in size. Internal muscles contract or relax to control the shape of the crystalline lens which focuses light rays onto the retina. This is what gives us the ability to see distant objects clearly and then to immediately change our focus to look at something up close. The retina acts as the film in a camera imprinting the pictures taken. The retina has extremely light sensitive cells which transmit the image through the optic nerve into the brain.
Other eye structures support the main activity of vision; there are six muscles attached to the eye which control the eye’s movements and direction. Lids and tears act as a protective barrier to lubricate and protect the cornea and blood vessels in the back of the eye nourish the retina.