The eye is amazingly complex with many interworking parts. In the front of the eye is a transparent structure called the cornea that helps to focus incoming light. The iris is a colored ring-shaped membrane found behind the cornea. In the middle of the iris is a circular opening called the pupil that expands and contracts depending on how much light enters the eye. A clear fluid known as the aqueous humor fills the area between the cornea and the iris.
Behind the pupil is clear structure called the crystalline lens surrounded by ciliary muscles that hold the lens in place and also assist in helping us see. To see objects far away, the muscles relax, pulling on the lens and flattening it. To see close objects, the muscle contracts, thus thickening the lens.
Inside the eyeball is found a jelly-like tissue called the vitreous humor. After light travels through the lens, the light travels through this tissue before hitting the retina. There are three layers of tissue in the eye. The outer layer is called the sclera. This layer gives the eyeball its white color. The middle layer is the choroid. It contains blood vessels that supply oxygen to the retina. The retina is the innermost layer. Embedded within the retina are millions of light sensitive cells that are divided into rods and cones. The rods help us see monochrome vision in low light conditions. The cones help us see colors and fine detail.
When light hits the rods and cones, the light is converted into an electrical impulse that is carried to the brain through the optic nerve. The brain translates the electric impulse into an image. This cleverly designed and complex process gives us sight. The eye is far more sophisticated then a camera, yet no one ever thinks that a camera appears by chance. Why believe that the eye appears by chance?