A cataract is a clouding of the normally clear and transparent lens of the eye.
When a cataract develops, the lens becomes as cloudy as a frosted window, and light cannot be properly focused on the retina, resulting in an unclear image. Often, only a small part of the lens is affected and, if sight is not greatly impaired, there is no need to remove the cataract. If a large portion of the lens becomes cloudy, sight may be partially or completely lost until the cataract is removed.
Cataracts related to ageing are the most common type, but cataracts can also result from hereditary factors, diseases, medications or injury. Although it's rare, cataracts also can affect children and young adults.
Blurred or double vision, ghost images, or the impression of a "film" over the eyes maybe noticed.
Sensitivity to bright light and glare may be a concern and the need for frequent changes of eye glass prescriptions - none of which seem to help.