The natural lens

The natural (or crystalline) lens is located in the front portion of the eye just behind the iris (coloured part of the eye). The role of the crystalline lens is to focus light on to the back of the eye to form a sharp image on the retina. The lens in a young person is able to flex from a thin lens to a thicker lens to focus vision for closer objects (this is known as accommodation). As we age this lens becomes more rigid and we lose the ability to focus at close range (presbyopia). With age the lens also becomes more opaque or cloudy (cataract) and we are unable to see clearly through it.

What is cataract?

The term cataract is used when the lens of the eye becomes cloudy. The most common cause for a cataract to form is the ageing process. More than 90% of patients over 90 years of age will have developed a cataract and half of these will have had surgery to remove the cataract. Cataract is not a reversible process. Changes to diet or sun exposure will not reverse the process. If left long enough cataracts can cause other eye conditions such as uveitis and glaucoma. Cataract is one of the leading causes of blindness in the world. In Australia it rarely causes blindness as patients have surgery before these other conditions develop.