ADVI is a diploma level course. It is a decreased ability to see to a degree that causes problems not fixable by usual means, such as glasses and some also involve those who have a decreased capability to see because they do not have access to glasses or contact lenses. It have sizeable economic costs both directly due to the cost of treatment and indirectly due to decreased ability to work. Visual impairment is often defined as a best rectify visual acuity of worse than either. The duration