The cataract denotes a turbidity of the eye lens. In a case of an advanced cataract one can recognize the gray or whitish turbidity behind the pupil. This is how the name came into being in German-speaking countries. Cataract (or cataracta) means waterfall or "falling down", which was inspired by the waterfalls in the upper Nile.
Almost every second person over the age of 65 is more or less affected by cloudiness of the eye lens. The treatment alternatives are based on the replacement of the opaque eye lens with an artificial lens. A drug therapy is not possible so far. Cataract surgery is the most commonly performed surgery on humans worldwide. In Germany over 600,000 eyes are operated annually.