The eye is made up of many individual parts, which work together to enable us to see. The IRIS is the coloured part that has a central opening which is black and called the PUPIL. The CORNEA is a clear curved structure which is both a protective coat and a lens and is in front of the iris. The ANTERIOR CHAMBER is the space between the cornea and iris. The anterior chamber stays formed from fluid also called AQUEOUS HUMOR and provides oxygen and nutients to keep the interior of the eye healthy.

The cornea is the most powerful lens in the eye's optical system. It is barely visible, because it is made up of a clear tissue. It’s curved shape means it acts like a lens, providing two thirds of the eye’s focusing power. The remaining power is supplied by the LENS, which sits inside the front of the eye behind the iris.

a normal eye

The RETINA is similar to the film in a camera and lines the back of the eye. It consists of nervous tissue and photoreceptors which converts light rays into electrical signals and sends them to the brain through the optic nerve.

The iris and lens work together like a camera, allowing light rays from an image to pass through to the retina at the back of the eye, where the image is captured upside-down. The brain then turns the image right-side-up. The lens changes shape to adjust the fine focus, depending on the distance between the eye and the object.

Sometimes the ability to focus clearly is compromised. This can be the result of the eye being abnormally short or long, or if the curvature of the cornea is too steep or flat. Both of these conditions can cause the focus point to fall inside or outside of the retina. This is common in long and short sighted people and referred to as a Refractive error.