CATARACT: simulation of cataract (opacity of the lens). Shows normal eye developing a cataract (lens becomes cloudy) and then being corrected by cataract (lens) removal and insertion of an intra ocular lens.
The animation begins with a vertical section of a normal human adult eye focused on infinity (or a distant object) with the light rays parallel. The lens becomes increasingly opaque and swollen as a cataract develops until much of the incoming light is blocked from reaching the retina. The cataract is then removed and light again reaches the retina unhindered. However, the accommodating power of the lens is lost and must be replaced by an artificial lens (an intra-ocular lens). This is shown very diagrammatically. Cataracts inevitably develop with age. However diseases and trauma can also cause them.