IN ORDER FOR YOU TO FULLY UNDERSTAND how orthokeratology works, you need to understand how your eye works. This basic knowledge will help you determine if accelerated ortho-k is right for you. The primary purpose of your eye is to focus light. When the rays of light are not focused properly, you need glasses or contact lenses.

Your eye works very much like a camera. Light enters the eye through the cornea, the clear front surface or "window" of the eye. As the light passes through the cornea, it is bent or refracted. This bent light then travels through the pupil and into the lens. The lens acts to fine-tune the focus of light onto the retina.The retina turns the light energy into electrical impulses that travel along the optic nerve from the eye to the brain, where the image is interpreted.

On the following pages is a series of pictures and short descriptions of the various parts of the eye that will help you understand the vision process. They explain why vision is sometimes blurry, and how common vision disorders can be corrected.

Diagram of Anatomy of the eye

Sclera

The sclera is the support layer of the eye. It is the white part of the eye that you see in the mirror and provides structure and protection for the eye.

Cornea

The cornea is the front-most surface of the eye, like the crystal of a watch. It provides most of the eye’s focusing power. Most of the refracting (bending) of light is achieved by the cornea, so small changes in the surface of the cornea can have a large effect on how your eye focuses light.

Pupil

The pupil is the black spot in the center of the iris. The pupil is an opening that regulates the amount of light that enters the eye. In bright sunlight it becomes small to let in less light. In a dark environment the pupil expands to allow more light to reach the retina.

Iris

The iris is the colored part of the eye. The muscles of the iris act to control the size of the pupil.

Lens

The lens is a normally clear structure located behind the pupil. It acts to increase focusing. By changing shape, the lens allows us to focus near and far. This ability to focus near (accommodation) gradually worsens with age as the lens be-comes more rigid and less supple. Most people notice this in their early forties, at which time they begin to need reading glasses or bifocals. In people more than sixty, the lens may become cloudy. This clouding of the lens is called a cataract and may interfere with your vision.

Vitreous

This is the clear gel substance that fills the space between the lens and the retina. If there are opacities in the vit-reous, you will see them as "floaters."

Retina

The retina is the thin layer of tissue that lines the inside wall of the eye. It is very similar to film in a camera in that it functions to capture and transmit images for interpreta-tion to the brain.

Optic Nerve
The optic nerve carries the images from the retina to the brain. The eye is a marvelous instrument that offers wonderful images to the brain and the clearer the vision the more enjoyable the view.

The eye is a marvelous, vital part of the body when all parts of the eye fuction properly.