It is a condition particularly related to aging. It is the leading cause of blindness in older people. Although there are different types of cataract, the most common is senile cataract which is what occurs with age. A cataract is the clouding of the crystalline lens of the eye, avoiding the entry of light needed making impossible clear images. Cataract treatment is always surgical and today, cataract surgery under normal conditions can return normal vision by the implant of special intraocular lens.