LY96 and age-related macular degeneration: The latterthree classes correspond to clinically recognized AMD phenotypes while the former twoclasses, MD1 and MD2, represent potential pre- or sub-clinical stages of AMD.Although occasional hard drusen are common in the adult population, elevated numbersof hard drusen, and in particular macular hard drusen (that is, MD1), are not commonand have been associated with an increased risk for developing AMD [111-114].