Cataracts are usually associated with the aging process. As a cataract ages the protein on the eye's lens becomes dense and opaque. Cataracts, when small, start as white and cloudy but as the protein on the lens ages it acquires a yellow or brown tint. While this tint itself doesn't lessen the sharpness of images seen it does make tasks having to do with color difficult as the tint effects what is seen through the lens of the eye. In advanced stages differentiating between dark colors can become difficult if not impossible. The eye's lens consists mostly of water and protein. When a cataracts is formed it clouds the lens and reduces the light entering the eye.
The first symptoms of a cataracts are a blurring around the ridge of the line of vision. The image it produces can be compared to looking through a window in winter that has frost around the edges. At this stage the cataracts is still small. While there won't be any real changes in vision aside from noticing the first symptoms, over time the cloudy area may get bigger as the cataracts increases in size. As the cataracts grows vision gets duller and blurrier. Development of cataracts is considered a normal part of the aging process. Roughly 70% of all people over the age of 75 have some kind of cataracts formation.
Cataracts develop not only from age but also from an injury to the eye. A blow directly to the eye, the eye socket or an injury directly to the eye lens can create traumatic cataracts. These injury-acquired cataracts sometimes wait to show themselves until years later. A metabolic problem or diabetes can aid in the development of cataracts as well due to the changes and fluctuations in body chemicals and proteins.
Cataracts can also be caused by long term use of certain oral steroids and medications such as those used to treat breast cancer (tamoxifen), medicines for the treatment of gout (allopurinol), and medication for the treatment of irregular heartbeat (amiadorone). Smoking has been linked to cataracts development. It has been found that the chemicals within inhaled smoke can be linked to the breaking down of the natural proteins in the eye. Exposure to radiation such as infrared and micro-waves have been associated with cataracts, as well as the use of alcohol.