A cataract is a clouding (opaqueness) of the normally clear lens of the eye. Cataracts are inevitable, to some degree, as we get older. Almost all of us will have some degree of cataract by the time we are 80.
The main cause of cataracts is getting older. Factors that increase your risk of cataract include:
Some cataracts are caused by inherited genetic disorders. Rubella infection in the womb can cause cataracts that are present from birth.
The problem caused by cataracts is that they interfere with vision. The lens of the eye is normally clear and focuses the light entering the pupil onto the retina - the light-sensitive layer at the back of the eye - to produce sharp images. A cataract scatters the light, blurring the images on the retina. Typically, people with cataract complain about difficulty in reading, recognising faces and driving at night. They may be sensitive to glare or see colours as faded or yellow.
The only effective treatment for a cataract is an operation. The damaged lens is removed and usually an artificial lens implant (called an intraocular lens) is inserted in its place. The operation may be done under local anaesthetic and requires only a short stay in hospital. Drops may be needed for some time afterwards and strenuous activity should be avoided.
The decision to operate depends entirely on how much the cataract interferes with your vision and ability to lead a normal life.
If you are in your 60s or older and your vision is deteriorating because of a cataract, then lens surgery might transform your life. Avoiding too much sunlight, and wearing a good pair of sunglasses in your younger years might help you avoid or postpone the need for an operation.
Last Reviewed: 18 June 2010