In ophthalmology, it is called cataracts to the total or parcial opacity of the crystalline.

• Congenital cataract: produced by an hereditary lesion or an agression on the embryo durign its development (e.g. rubella)

• Acquired cataract: it is the most common and the main cause of vision loss between the people over 55 years old. It is caused for the acumulation of dead cells in the natural lens of the eyes, which are in charge of focus the light and produce clear and clear up images. There are many modalities.