Cataract is defined as opacity of the crystalline lens. Age is by far the biggest risk factor for cataract, and it is sometimes assumed that cataract is simply an amplification of this aging process. Age-related cataract appears to accompany the latter stages of lifespan inmost cases. With aging, the molecular changes that take place in the crystalline lens that contribute to a gradual reduction in transparency. In many cases, the aging process of the crystalline lens reaches a point where vision is impaired.. However, no method to halt the formation of a cataractous lens has been shown to be effective so far but researches are in progress. Nevertheless, advances in surgical removal of cataracts, including small-incision surgery, use of viscoelastics, and the development of intraocular lenses, have made treatment very effective and visual recovery is rapid in most cases. Despite these advances, cataract continues to be a leading public-health issue with greater life expectancy