This depends on the density of the clouding and the extent of the area of the lens involved. Long-term use of certain medicines, such as Corticosteroids. Medical conditions such as diabetes. In uncommon cases, cataracts may be inherited. Additionally, there is some evidence that years of exposure to the ultraviolet rays of the sun may play a role in cataract development.
Cataracts usually develop gradually over a number of years.
In most cases, they form in both eyes, though not usually at the same rate. A person may or may not be aware that a cataract is developing. The main symptom of cataract formation is painless loss of vision. The visual effects if any depend on the size, location and density of the cataract. Blurred or double vision.