What is cataract?
Mr Ursell explains the condition. Watch our film here.
A patient experience of life after surgery. Watch our film.
How does the eye see?
Before we look at how a cataract develops it is necessary to find out how the normal eye works.
The eye functions like a camera. There is a focusing part at the front that produces a sharp image on the retina at the back of the eye.
The focusing part consists of the cornea and the lens. The pupil is like the aperture of a camera, regulating the amount of light entering the eye.
The retina contains special cells called rods and cones that register the light and turn it into electrical impulses that are sent to the brain so that we can see.
Fine vision such as reading is performed by a small central part of the retina called the macula.
How are cataracts formed?
The majority of cataracts occur as a part of the normal ageing process in the lens.
In some people who suffer from diabetes or eye diseases such as uveitis, they form slightly quicker. Cataracts can be hereditary and are sometimes seen in children.
Cataracts manifest as cloudiness and opacity within the lens inside the eye. Normally this lens is crystal clear and its purpose is to focus light onto the retina at the back of the eye.
Cataract formation is like the process of cooking an egg. At the start of cooking, the egg white is clear but steadily becomes opaque. A similar process occurs in the lens of the eye. The cloudy lens will not transmit light clearly on the retina therefore causing blurred vision.