Inside our eyes there is a natural lens, this sits just behind the iris, the coloured part of our eye. When this biological lens of the eye goes hazy it is called a cataract.
The lens of a young child is very thin and very clear, every day new lens fibres grow and the lens gets bigger. As the lens increases in size, its flexibility reduces correspondingly. This reduction in flexibility translates into less capability to change focus; hence, a child being able to see small objects within 10cm while most adults struggle to do this. As more and more fibres are added to the lens its transparency is no longer maintained. This is the most common way a cataract is formed.
Cataract is a general term referring to loss of transparency of the lens. Usually this hazing occurs gradually over time, as outlined above. Cataracts can be caused or develop earlier than they would naturally due to UV exposure, ocular trauma, disease or medication. The fibres of the lens are arranged in a very particular way and trauma can upset this arrangement which leads to reduced transparency. Conditions such as diabetes can cause cataracts to form earlier as can steroid use.
How can I tell whether I have a cataract?
Cataracts cause a number of symptoms including reduced vision, increased sensitivity to glare, loss of contrast sensitivity and/or a frequently changing spectacle prescription. An optometrist can diagnose and assess cataracts. If your cataract/s requires treatment you will be referred to an ophthalmologist.
What can be done?
Often nothing is done when a cataract is first diagnosed, in some cases they are monitored over a number of years. When vision is no longer adequate to comfortably perform day to day tasks such as reading or driving cataract surgery is considered.
Cataract surgery includes removing the hazy lens and replacing it with a clear plastic lens. Cataract surgery is a very safe procedure, in fact it is one of the most successful and commonly performed surgeries in first world countries.