What is a Cataract?

Every eye contains a small lens. The job of the lens is to focus light which enters the front of the eye to form a picture at the back of the eye (the retina). In a young person, the lens of the eye is clear but it becomes gradually cloudier with increasing age - like a window which is never washed. When there is a cloudy area in the lens of the eye, it is called a cataract. A cataract blocks light entering the eye and interferes with focusing. As a cataract develops, the eyesight becomes worse, even if the correct spectacles are worn.

Cataracts are a normal feature of aging. About half of adults aged 65 to 74 have cataracts.

Cataracts normally develop slowly but can occasionally worsen over a short period. Very occasionally they can develop for reasons other than normal aging.

Most people with cataracts have one in each eye. Sometimes, a cataract may develop earlier in one eye causing the vision to be worse in that eye.

Many people with cataracts don't even know it. Their cataract may be mild, or the changes in their vision may not bother them very much. Other people who have cataracts cannot see well enough to do the things they need or want to do.