Cataracts are a very common eye condition. As we get older the lens inside our eye gradually changes and becomes less transparent (clear). A lens that has turned misty, or cloudy, is said to have a cataract. Over time a cataract can get worse, gradually making your vision misty or cloudy. A straightforward operation can usually remove the misty lens and replace it with an artificial lens to enable you to see more clearly again.
Your optometrist may inform you at a routine eye examination that you have the early signs of cataract but this does not mean that surgery is imminent. It may be many years before the cataract advances to a point where it significantly impairs your vision and it is usually only at this time that surgery is advised.
The information above is about cataracts in adults. Some children develop cataracts before or just after birth which are called congenital cataracts. These are usually treated differently from cataracts in adults.
For more detailed information about the causes and treatment of cataracts follow the link to RNIB