The clear lens on the eye, behind the iris, which focuses light to provide sharp images, becomes cloudy and hardens causing a loss of sight.
As less light is able to pass through the lens, your vision may become blurry or cloudy. The cloudier the lens becomes, the more your sight will be affected.
Cataracts are painless and gradually develop over a long period of time. Over 50% of people aged over 65 have some form of cataract development and most cases can be treated successfully with surgery where the lens is replaced by a clear plastic one.