It is where the lens of the eye becomes cloudy, so it is difficult to see through.
You may find:
The lens is inside the eye directly behind the coloured part, which is called the iris. Little muscles are attached to the lens. These move, and by slightly altering its shape they help you focus on what you want to see.
The most common cause is ageing, but occasionally they happen because of injury, or as a complication of other conditions.
In the early stages of cataract, spectacles may help you see clearly enough.
When your vision has become so poor that it seriously affects everyday life - such as driving, watching TV, or reading - then your optometrist will refer you to an eye specialist, called an ophthalmologist, in the hospital. The ophthalmologist will assess your eyes and help you decide about an operation.
It is often carried out under local anesthetic, and usually as a day-case procedure (no overnight stay). The cloudy lens inside your eye is removed and replaced with a new, clear lens made of special plastic. Afterwards, your visi